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Friday, September 8, 2023

Christianity and Judaism

From Wikipedia, the free encyclopedia

Christianity began as a movement within Second Temple Judaism, but the two religions gradually diverged over the first few centuries of the Christian Era. Today, differences of opinion vary between denominations in both religions, but the most important distinction is Christian acceptance and Jewish non-acceptance of Jesus as the Messiah prophesized in the Hebrew Bible and Jewish tradition. Early Christianity distinguished itself by determining that observance of halakha (Jewish law) was not necessary for non-Jewish converts to Christianity (See Pauline Christianity). Another major difference is the two religions' conceptions of God. The Christian God consists of three persons of one essence (Father, Son and Holy Spirit), with the doctrine of the incarnation of the Son in Jesus being of special importance. Judaism emphasizes the Oneness of God and rejects the Christian concept of God in human form. While Christianity recognizes the Hebrew Bible (called the Old Testament by Christians) as part of its scriptural canon, Judaism does not recognize the Christian New Testament.

The relative importance of belief and practice constitute an important area of difference. Most forms of Protestant Christianity emphasize correct belief (or orthodoxy), focusing on the New Covenant as mediated through Jesus Christ, as recorded in the New Testament. Judaism places emphasis on correct conduct (or orthopraxy), focusing on the Mosaic covenant, as recorded in the Torah and Talmud. Mainstream Roman Catholicism occupies a middle position, stating the both faith and works are factors in a person's salvation. Some schools of thought within Catholicism, such as Franciscanism and liberation theology, explicitly favor orthopraxy over orthodoxy. Praxis is of central importance to Eastern Christianity as well, with Saint Maximus the Confessor going as far as to say that "theology without action is the theology of demons." Christian conceptions of right practice vary (e.g., Catholic social teaching and its preferential option for the poor; the Eastern Orthodox Church's practices of fasting, hesychasm, and asceticism; the Protestant work ethic of Calvinists and others), but differ from Judaism in that they are not based on following halakha or any other interpretation of the Mosaic covanent. While more liberal Jewish denominations may not require observance of halakha, Jewish life remains centred on individual and collective participation in an eternal dialogue with God through tradition, rituals, prayers and ethical actions.

Jewish self-identification

Judaism's purpose is to carry out what it holds to be the covenant between God and the Jewish people. The Torah (lit.'teaching'), both written and oral, tells the story of this covenant, and provides Jews with the terms of the covenant. The Oral Torah is the primary guide for Jews to abide by these terms, as expressed in tractate Gittin 60b ("the Holy One, Blessed be He, did not make His covenant with Israel except by virtue of the Oral Law") to help them learn how to live a holy life, and to bring holiness, peace and love into the world and into every part of life, so that life may be elevated to a high level of kedushah, originally through study and practice of the Torah, and since the destruction of the Second Temple, through prayer as expressed in tractate Sotah 49a "Since the destruction of the Temple, every day is more cursed than the preceding one; and the existence of the world is assured only by the kedusha...and the words spoken after the study of Torah."

Since the adoption of the Amidah, the acknowledgement of God through the declaration from Isaiah 6:3 "Kadosh [holy], kadosh, kadosh, is HaShem, Master of Legions; the whole world is filled with His glory". as a replacement for the study of Torah, which is a daily obligation for a Jew, and sanctifies God in itself. This continuous maintenance of relationship between the individual Jew and God through either study, or prayer repeated three times daily, is the confirmation of the original covenant. This allows the Jewish people as a community to strive and fulfill the prophecy "I, the Lord, have called you in righteousness, and will hold your hand and keep you. And I will establish you as a covenant of the people, for a light unto the nations." (i.e., a role model) over the course of history, and a part of the divine intent of bringing about an age of peace and sanctity where ideally a faithful life and good deeds should be ends in themselves, not means (see also Jewish principles of faith).

According to Christian theologian Alister McGrath, the Jewish Christians affirmed every aspect of then contemporary Second Temple Judaism with the addition of the belief that Jesus was the messiah, with Isaiah 49:6, "an explicit parallel to 42:6" quoted by Paul the Apostle in Acts 13:47 and reinterpreted by Justin Martyr. According to Christian writers, most notably Paul, the Bible teaches that people are, in their current state, sinful, and the New Testament reveals that Jesus is both the Son of man and the Son of God, united in the hypostatic union, God the Son, God made incarnate; that Jesus' death by crucifixion was a sacrifice to atone for all of humanity's sins, and that acceptance of Jesus as Savior and Lord saves one from Divine Judgment, giving Eternal life. Jesus is the mediator of the New Covenant. His famous Sermon on the Mount is considered by some Christian scholars to be the proclamation of the New Covenant ethics, in contrast to the Mosaic Covenant of Moses from Mount Sinai.

Sacred texts

The Hebrew Bible is composed of three parts; the Torah (Instruction, the Septuagint translated the Hebrew to nomos or Law), the Nevi'im (Prophets) and the Ketuvim (Writings). Collectively, these are known as the Tanakh. According to Rabbinic Judaism the Torah was revealed by God to Moses; within it, Jews find 613 Mitzvot (commandments).

Rabbinic tradition asserts that God revealed two Torahs to Moses, one that was written down, and one that was transmitted orally. Whereas the written Torah has a fixed form, the Oral Torah is a living tradition that includes not only specific supplements to the written Torah (for instance, what is the proper manner of shechita and what is meant by "Frontlets" in the Shema), but also procedures for understanding and talking about the written Torah (thus, the Oral Torah revealed at Sinai includes debates among rabbis who lived long after Moses). The Oral Law elaborations of narratives in the Bible and stories about the rabbis are referred to as aggadah. It also includes elaboration of the 613 commandments in the form of laws referred to as halakha. Elements of the Oral Torah were committed to writing and edited by Judah HaNasi in the Mishnah in 200 CE; much more of the Oral Torah were committed to writing in the Babylonian and Jerusalem Talmuds, which were edited around 600 CE and 450 CE, respectively. The Talmuds are notable for the way they combine law and lore, for their explication of the midrashic method of interpreting texts, and for their accounts of debates among rabbis, which preserve divergent and conflicting interpretations of the Bible and legal rulings.

Since the transcription of the Talmud, notable rabbis have compiled law codes that are generally held in high regard: the Mishneh Torah, the Tur, and the Shulchan Aruch. The latter, which was based on earlier codes and supplemented by the commentary by Moshe Isserles that notes other practices and customs practiced by Jews in different communities, especially among Ashkenazim, is generally held to be authoritative by Orthodox Jews. The Zohar, which was written in the 13th century, is generally held as the most important esoteric treatise of the Jews.

All contemporary Jewish movements consider the Tanakh, and the Oral Torah in the form of the Mishnah and Talmuds as sacred, although movements are divided as to claims concerning their divine revelation, and also their authority. For Jews, the Torah—written and oral—is the primary guide to the relationship between God and man, a living document that has unfolded and will continue to unfold whole new insights over the generations and millennia. A saying that captures this goes, "Turn it [the Torah's words] over and over again, for everything is in it."

Christians accept the Written Torah and other books of the Hebrew Bible (alternatively called Old Testament) as Scripture, although they generally give readings from the Koine Greek Septuagint translation instead of the Biblical Hebrew/Biblical Aramaic Masoretic Text. Two notable examples are:

  • Isaiah 7:14 – "virgin" instead of "young woman"
  • Psalm 22:16 – "they have pierced my hands and feet" instead of "like a lion, (they are at) my hands and feet"

Instead of the traditional Jewish order and names for the books, Christians organize and name the books closer to that found in the Septuagint. Some Christian denominations (such as Anglican, Roman Catholic, and Eastern Orthodox), include a number of books that are not in the Hebrew Bible (the biblical apocrypha or deuterocanonical books or Anagignoskomena, see Development of the Old Testament canon) in their biblical canon that are not in today's Jewish canon, although they were included in the Septuagint. Christians reject the Jewish Oral Torah, which was still in oral, and therefore unwritten, form in the time of Jesus.

Jesus depicted delivering the Sermon on the Mount which included commentary on the Old Covenant. Some scholars consider this to be an antitype of the proclamation of the Ten Commandments or Mosaic Covenant by Moses from the Biblical Mount Sinai.

Covenant theology

Christians believe that God has established a New Covenant with people through Jesus, as recorded in the Gospels, Acts of the Apostles, Epistles, and other books collectively called the New Testament (the word testament attributed to Tertullian is commonly interchanged with the word covenant). For some Christians, such as Roman Catholics and Orthodox Christians, this New Covenant includes authoritative sacred traditions and canon law. Others, especially Protestants, reject the authority of such traditions and instead hold to the principle of sola scriptura, which accepts only the Bible itself as the final rule of faith and practice. Anglicans do not believe in sola scriptura. For them scripture is the longest leg of a 3-legged stool: scripture, tradition and reason. Scripture cannot stand on its own since it must be interpreted in the light of the Church's patristic teaching and ecumenical creeds. Additionally, some denominations include the "oral teachings of Jesus to the Apostles", which they believe have been handed down to this day by apostolic succession.

Christians refer to the biblical books about Jesus as the New Testament, and to the canon of Hebrew books as the Old Testament. Judaism does not accept the retronymic labeling of its sacred texts as the "Old Testament", and some Jews refer to the New Testament as the Christian Testament or Christian Bible. Judaism rejects all claims that the Christian New Covenant supersedes, abrogates, fulfills, or is the unfolding or consummation of the covenant expressed in the Written and Oral Torahs. Therefore, just as Christianity does not accept that Mosaic law has any authority over Christians, Judaism does not accept that the New Testament has any religious authority over Jews.

Law

Many Jews view Christians as having quite an ambivalent view of the Torah, or Mosaic law: on one hand Christians speak of it as God's absolute word, but on the other, they apply its commandments with a certain selectivity. Some Jews contend that Christians cite commandments from the Old Testament to support one point of view but then ignore other commandments of a similar class and of equal weight. Examples of this are certain commandments that God states explicitly be a "lasting covenant." Some translate the Hebrew as a "perpetual covenant."

Christians explain that such selectivity is based on rulings made by early Jewish Christians in the Book of Acts, at the Council of Jerusalem, that, while believing gentiles did not need to fully convert to Judaism, they should follow some aspects of Torah like avoiding idolatry and fornication and blood. This view is also reflected by modern Judaism, in that Righteous gentiles need not convert to Judaism and need to observe only the Noahide Laws, which also contain prohibitions against idolatry and fornication and blood.

Some Christians agree that Jews who accept Jesus should still observe all of Torah, see for example Dual-covenant theology, based on warnings by Jesus to Jews not to use him as an excuse to disregard it, and they support efforts of those such as Messianic Jews (Messianic Judaism is considered by most Christians and Jews to be a form of Christianity) to do that, but some Protestant forms of Christianity oppose all observance to the Mosaic law, even by Jews, which Luther criticised as Antinomianism.

A minority view in Christianity, known as Christian Torah-submission, holds that the Mosaic law as it is written is binding on all followers of God under the New Covenant, even for gentiles, because it views God's commands as "everlasting" and "good."

Concepts of God

Traditionally, both Judaism and Christianity believe in the God of Abraham, Isaac and Jacob, for Jews the God of the Tanakh, for Christians the God of the Old Testament, the creator of the universe. Judaism and major sects of Christianity reject the view that God is entirely immanent (although some see this as the concept of the Holy Ghost) and within the world as a physical presence (although Christians believe in the incarnation of God). Both religions reject the view that God is entirely transcendent, and thus separate from the world, as the pre-Christian Greek Unknown God. Both religions reject atheism on one hand and polytheism on the other.

Both religions agree that God shares both transcendent and immanent qualities. How these religions resolve this issue is where the religions differ. Christianity posits that God exists as a Trinity; in this view God exists as three distinct persons who share a single divine essence, or substance. In those three there is one, and in that one there are three; the one God is indivisible, while the three persons are distinct and unconfused, God the Father, God the Son, and God the Holy Spirit. It teaches that God became especially immanent in physical form through the Incarnation of God the Son who was born as Jesus of Nazareth, who is believed to be at once fully God and fully human. There are denominations self-describing as Christian who question one or more of these doctrines, however, see Nontrinitarianism. By contrast, Judaism sees God as a single entity, and views trinitarianism as both incomprehensible and a violation of the Bible's teaching that God is one. It rejects the notion that Jesus or any other object or living being could be 'God', that God could have a literal 'son' in physical form or is divisible in any way, or that God could be made to be joined to the material world in such fashion. Although Judaism provides Jews with a word to label God's transcendence (Ein Sof, without end) and immanence (Shekhinah, in-dwelling), these are merely human words to describe two ways of experiencing God; God is one and indivisible.

Shituf

A minority Jewish view, which appears in some codes of Jewish law, is that while Christian worship is polytheistic (due to the multiplicity of the Trinity), it is permissible for them to swear in God's name, since they are referring to the one God. This theology is referred to in Hebrew as Shituf (literally "partnership" or "association"). Although worship of a trinity is considered to be not different from any other form of idolatry for Jews, it may be an acceptable belief for non-Jews (according to the ruling of some Rabbinic authorities).

Right action

Faith versus good deeds

Judaism teaches that the purpose of the Torah is to teach us how to act correctly. God's existence is a given in Judaism, and not something that most authorities see as a matter of required belief. Although some authorities see the Torah as commanding Jews to believe in God, Jews see belief in God as a necessary, but not sufficient, condition for a Jewish life. The quintessential verbal expression of Judaism is the Shema Yisrael, the statement that the God of the Bible is their God, and that this God is unique and one. The quintessential physical expression of Judaism is behaving in accordance with the 613 Mitzvot (the commandments specified in the Torah), and thus live one's life in God's ways.

Thus fundamentally in Judaism, one is enjoined to bring holiness into life (with the guidance of God's laws), rather than removing oneself from life to be holy.

Much of Christianity also teaches that God wants people to perform good works, but all branches hold that good works alone will not lead to salvation, which is called Legalism, the exception being dual-covenant theology. Some Christian denominations hold that salvation depends upon transformational faith in Jesus, which expresses itself in good works as a testament (or witness) to ones faith for others to see (primarily Eastern Orthodox Christianity and Roman Catholicism), while others (including most Protestants) hold that faith alone is necessary for salvation. Some argue that the difference is not as great as it seems, because it really hinges on the definition of "faith" used. The first group generally uses the term "faith" to mean "intellectual and heartfelt assent and submission". Such a faith will not be salvific until a person has allowed it to effect a life transforming conversion (turning towards God) in their being (see Ontotheology). The Christians that hold to "salvation by faith alone" (also called by its Latin name "sola fide") define faith as being implicitly ontological—mere intellectual assent is not termed "faith" by these groups. Faith, then, is life-transforming by definition.

Sin

In both religions, offenses against the will of God are called sin. These sins can be thoughts, words, or deeds.

Catholicism categorizes sins into various groups. A wounding of the relationship with God is often called venial sin; a complete rupture of the relationship with God is often called mortal sin. Without salvation from sin (see below), a person's separation from God is permanent, causing such a person to enter Hell in the afterlife. Both the Catholic Church and the Orthodox Church define sin more or less as a "macula", a spiritual stain or uncleanliness that constitutes damage to man's image and likeness of God.

Hebrew has several words for sin, each with its own specific meaning. The word pesha, or "trespass", means a sin done out of rebelliousness. The word aveira means "transgression". And the word avone, or "iniquity", means a sin done out of moral failing. The word most commonly translated simply as "sin", het, literally means "to go astray". Just as Jewish law, halakha provides the proper "way" (or path) to live, sin involves straying from that path. Judaism teaches that humans are born with free will, and morally neutral, with both a yetzer hatov, (literally, "the good inclination", in some views, a tendency towards goodness, in others, a tendency towards having a productive life and a tendency to be concerned with others) and a yetzer hara, (literally "the evil inclination", in some views, a tendency towards evil, and in others, a tendency towards base or animal behavior and a tendency to be selfish). In Judaism all human beings are believed to have free will and can choose the path in life that they will take. It does not teach that choosing good is impossible—only at times more difficult. There is almost always a "way back" if a person wills it. (Although texts mention certain categories for whom the way back will be exceedingly hard, such as the slanderer, the habitual gossip, and the malicious person)

The rabbis recognize a positive value to the yetzer hara: one tradition identifies it with the observation on the last day of creation that God's accomplishment was "very good" (God's work on the preceding days was just described as "good") and explain that without the yetzer ha'ra there would be no marriage, children, commerce or other fruits of human labor; the implication is that yetzer ha'tov and yetzer ha'ra are best understood not as moral categories of good and evil but as selfless versus selfish orientations, either of which used rightly can serve God's will.

In contrast to the Jewish view of being morally balanced, Original Sin refers to the idea that the sin of Adam and Eve's disobedience (sin "at the origin") has passed on a spiritual heritage, so to speak. Christians teach that human beings inherit a corrupted or damaged human nature in which the tendency to do bad is greater than it would have been otherwise, so much so that human nature would not be capable now of participating in the afterlife with God. This is not a matter of being "guilty" of anything; each person is only personally guilty of their own actual sins. However, this understanding of original sin is what lies behind the Christian emphasis on the need for spiritual salvation from a spiritual Saviour, who can forgive and set aside sin even though humans are not inherently pure and worthy of such salvation. Paul the Apostle in Romans and I Corinthians placed special emphasis on this doctrine, and stressed that belief in Jesus would allow Christians to overcome death and attain salvation in the hereafter.

Roman Catholics, Eastern Orthodox Christians, and some Protestants teach the Sacrament of Baptism is the means by which each person's damaged human nature is healed and sanctifying grace (capacity to enjoy and participate in the spiritual life of God) is restored. This is referred to as "being born of water and the Spirit", following the terminology in the Gospel of St. John. Most Protestants believe this salvific grace comes about at the moment of personal decision to follow Jesus, and that baptism is a symbol of the grace already received.

Love

The Hebrew word for "love", ahavah (אהבה), is used to describe intimate or romantic feelings or relationships, such as the love between parent and child in Genesis 22:2; 25: 28; 37:3; the love between close friends in I Samuel 18:2, 20:17; or the love between a young man and young woman in Song of Songs. Christians will often use the Greek of the Septuagint to make distinctions between the types of love: philia for brotherly, eros for romantic and agape for self-sacrificing love.

Like many Jewish scholars and theologians, literary critic Harold Bloom understands Judaism as fundamentally a religion of love. But he argues that one can understand the Hebrew conception of love only by looking at one of the core commandments of Judaism, Leviticus 19:18, "Love your neighbor as yourself", also called the second Great Commandment. Talmudic sages Hillel and Rabbi Akiva commented that this is a major element of the Jewish religion. Also, this commandment is arguably at the center of the Jewish faith. As the third book of the Torah, Leviticus is literally the central book. Historically, Jews have considered it of central importance: traditionally, children began their study of the Torah with Leviticus, and the midrashic literature on Leviticus is among the longest and most detailed of midrashic literature. Bernard Jacob Bamberger considers Leviticus 19, beginning with God's commandment in verse 3—"You shall be holy, for I the Lord your God, am holy"—to be "the climactic chapter of the book, the one most often read and quoted" (1981:889). Leviticus 19:18 is itself the climax of this chapter.

Abortion

The only statements in the Tanakh about the status of a fetus state that killing an unborn infant does not have the same status as killing a born human being, and mandates a much lesser penalty. (Although this interpretation is disputed, the passage could refer to an injury to a woman that causes a premature, live birth).

The Talmud states that the fetus is not yet a full human being until it has been born (either the head or the body is mostly outside of the woman), therefore killing a fetus is not murder, and abortion—in restricted circumstances—has always been legal under Jewish law. Rashi, the great 12th century commentator on the Bible and Talmud, states clearly of the fetus lav nefesh hu: "it is not a person". The Talmud contains the expression ubar yerech imo—the fetus is as the thigh of its mother,' i.e., the fetus is deemed to be part and parcel of the pregnant woman's body." The Babylonian Talmud Yevamot 69b states that: "the embryo is considered to be mere water until the fortieth day." Afterwards, it is considered subhuman until it is born. Christians who agree with these views may refer to this idea as abortion before the quickening of the fetus.

Judaism unilaterally supports, in fact mandates, abortion if doctors believe that it is necessary to save the life of the woman. Many rabbinic authorities allow abortions on the grounds of gross genetic imperfections of the fetus. They also allow abortion if the woman were suicidal because of such defects. However, Judaism holds that abortion is impermissible for family planning or convenience reasons. Each case must be decided individually, however, and the decision should lie with the pregnant woman, the man who impregnated her, and their Rabbi.

War, violence and pacifism

Jews and Christians accept as valid and binding many of the same moral principles taught in the Torah. There is a great deal of overlap between the ethical systems of these two faiths. Nonetheless, there are some highly significant doctrinal differences.

Judaism has many teachings about peace and compromise, and its teachings make physical violence the last possible option. Nonetheless, the Talmud teaches that "If someone comes with the intention to murder you, then one is obligated to kill in self-defense [rather than be killed]". The clear implication is that to bare one's throat would be tantamount to suicide (which Jewish law forbids) and it would also be considered helping a murderer kill someone and thus would "place an obstacle in front of a blind man" (i.e., makes it easier for another person to falter in their ways). The tension between the laws dealing with peace, and the obligation to self-defense, has led to a set of Jewish teachings that have been described as tactical-pacifism. This is the avoidance of force and violence whenever possible, but the use of force when necessary to save the lives of one's self and one's people.

Although killing oneself is forbidden under normal Jewish law as being a denial of God's goodness in the world, under extreme circumstances when there has seemed no choice but to either be killed or forced to betray their religion, Jews have committed suicide or mass suicide (see Masada, First French persecution of the Jews, and York Castle for examples). As a grim reminder of those times, there is even a prayer in the Jewish liturgy for "when the knife is at the throat", for those dying "to sanctify God's Name". These acts have received mixed responses by Jewish authorities. Where some Jews regard them as examples of heroic martyrdom, but others saying that while Jews should always be willing to face martyrdom if necessary, it was wrong for them to take their own lives.

Because Judaism focuses on this life, many questions to do with survival and conflict (such as the classic moral dilemma of two people in a desert with only enough water for one to survive) were analysed in great depth by the rabbis within the Talmud, in the attempt to understand the principles a godly person should draw upon in such a circumstance.

The Sermon on the Mount records that Jesus taught that if someone comes to harm you, then one must turn the other cheek. This has led four Protestant Christian denominations to develop a theology of pacifism, the avoidance of force and violence at all times. They are known historically as the peace churches, and have incorporated Christ's teachings on nonviolence into their theology so as to apply it to participation in the use of violent force; those denominations are the Quakers, Mennonites, Amish, and the Church of the Brethren. Many other churches have people who hold to the doctrine without making it a part of their doctrines, or who apply it to individuals but not to governments, see also Evangelical counsels. The vast majority of Christian nations and groups have not adopted this theology, nor have they followed it in practice. See also But to bring a sword.

Capital punishment

Although the Hebrew Bible has many references to capital punishment, the Jewish sages used their authority to make it nearly impossible for a Jewish court to impose a death sentence. Even when such a sentence might have been imposed, the Cities of Refuge and other sanctuaries, were at hand for those unintentionally guilty of capital offences. It was said in the Talmud about the death penalty in Judaism, that if a court killed more than one person in seventy years, it was a barbarous (or "bloody") court and should be condemned as such.

Christianity usually reserved the death penalty for heresy, the denial of the orthodox view of God's view, and witchcraft or similar non-Christian practices. For example, in Spain, unrepentant Jews were exiled, and it was only those crypto-Jews who had accepted baptism under pressure but retained Jewish customs in private, who were punished in this way. It is presently acknowledged by most of Christianity that these uses of capital punishment were deeply immoral.

Taboo food and drink

Orthodox Jews, unlike most Christians, still practice a restrictive diet that has many rules. Most Christians believe that the kosher food laws have been superseded, for example citing what Jesus taught in Mark 7: what you eat doesn't make you unclean but what comes out of a man's heart makes him unclean—although Roman Catholicism and Eastern Orthodoxy have their own set of dietary observances. Eastern Orthodoxy, in particular has very elaborate and strict rules of fasting, and continues to observe the Council of Jerusalem's apostolic decree of Act 15.

Some Christian denominations observe some biblical food laws, for example the practice of Ital in Rastafari. Jehovah's Witnesses do not eat blood products and are known for their refusal to accept blood transfusions based on not "eating blood".

Salvation

Judaism does not see human beings as inherently flawed or sinful and needful of being saved from it, but rather capable with a free will of being righteous, and unlike Christianity does not closely associate ideas of "salvation" with a New Covenant delivered by a Jewish messiah, although in Judaism Jewish people will have a renewed national commitment of observing God's commandments under the New Covenant, and the Jewish Messiah will also be ruling at a time of global peace and acceptance of God by all people.

Judaism holds instead that proper living is accomplished through good works and heartfelt prayer, as well as a strong faith in God. Judaism also teaches that gentiles can receive a share in "the world to come". This is codified in the Mishna Avot 4:29, the Babylonian Talmud in tractates Avodah Zarah 10b, and Ketubot 111b, and in Maimonides's 12th century law code, the Mishneh Torah, in Hilkhot Melachim (Laws of Kings) 8.11.

The Protestant view is that every human is a sinner, and being saved by God's grace, not simply by the merit of one's own actions, pardons a damnatory sentence to Hell.

Forgiveness

In Judaism, one must go to those he has harmed to be entitled to forgiveness. This means that in Judaism a person cannot obtain forgiveness from God for wrongs the person has done to other people. This also means that, unless the victim forgave the perpetrator before he died, murder is unforgivable in Judaism, and they will answer to God for it, though the victims' family and friends can forgive the murderer for the grief they caused them.

Thus the "reward" for forgiving others is not God's forgiveness for wrongs done to others, but rather help in obtaining forgiveness from the other person.

Sir Jonathan Sacks, Chief Rabbi of the United Hebrew Congregations of the Commonwealth, summarized: "it is not that God forgives, while human beings do not. To the contrary, we believe that just as only God can forgive sins against God, so only human beings can forgive sins against human beings."

Judgment

Both Christianity and Judaism believe in some form of judgment. Most Christians (the exception is Full Preterism) believe in the future Second Coming of Jesus, which includes the Resurrection of the Dead and the Last Judgment. Those who have accepted Jesus as their personal saviour will be saved and live in God's presence in the Kingdom of Heaven, those who have not accepted Jesus as their saviour, will be cast into the Lake of fire (eternal torment, finite torment, or simply annihilated), see for example The Sheep and the Goats.

In Jewish liturgy there is significant prayer and talk of a "book of life" that one is written into, indicating that God judges each person each year even after death. This annual judgment process begins on Rosh Hashanah and ends with Yom Kippur. Additionally, God sits daily in judgment concerning a person's daily activities. Upon the anticipated arrival of the Messiah, God will judge the nations for their persecution of Israel during the exile. Later, God will also judge the Jews over their observance of the Torah.

Heaven and Hell

There is little Jewish literature on heaven or hell as actual places, and there are few references to the afterlife in the Hebrew Bible. One is the ghostly apparition of Samuel, called up by the Witch of Endor at King Saul's command. Another is a mention by the Prophet Daniel of those who sleep in the earth rising to either everlasting life or everlasting abhorrence.

Early Hebrew views were more concerned with the fate of the nation of Israel as a whole, rather than with individual immortality. A stronger belief in an afterlife for each person developed during the Second Temple period but was contested by various Jewish sects. Pharisees believed that in death, people rest in their graves until they are physically resurrected with the coming of the Messiah, and within that resurrected body the soul would exist eternally. Maimonides also included the concept of resurrection in his Thirteen Principles of Faith.

Judaism's view is summed up by a biblical observation about the Torah: in the beginning God clothes the naked (Adam), and at the end God buries the dead (Moses). The Children of Israel mourned for 40 days, then got on with their lives.

In Judaism, Heaven is sometimes described as a place where God debates Talmudic law with the angels, and where Jews spend eternity studying the Written and Oral Torah. Jews do not believe in "Hell" as a place of eternal torment. Gehenna is a place or condition of purgatory where Jews spend up to twelve months purifying to get into heaven, depending on how sinful they have been, although some suggest that certain types of sinners can never be purified enough to go to heaven and rather than facing eternal torment, simply cease to exist. Therefore, some violations like suicide would be punished by separation from the community, such as not being buried in a Jewish cemetery (in practice, rabbis often rule suicides to be mentally incompetent and thus not responsible for their actions). Judaism also does not have a notion of hell as a place ruled by Satan since God's dominion is total and Satan is only one of God's angels.

Catholics also believe in a purgatory for those who are going to heaven, but Christians in general believe that Hell is a fiery place of torment that never ceases, called the Lake of Fire. A small minority believe this is not permanent, and that those who go there will eventually either be saved or cease to exist. Heaven for Christians is depicted in various ways. As the Kingdom of God described in the New Testament and particularly the Book of Revelation, Heaven is a new or restored earth, a World to Come, free of sin and death, with a New Jerusalem led by God, Jesus, and the most righteous of believers starting with 144,000 Israelites from every tribe, and all others who received salvation living peacefully and making pilgrimages to give glory to the city.

In Christianity, promises of Heaven and Hell as rewards and punishments are often used to motivate good and bad behavior, as threats of disaster were used by prophets like Jeremiah to motivate the Israelites. Modern Judaism generally rejects this form of motivation, instead teaching to do the right thing because it's the right thing to do. As Maimonides wrote:

"A man should not say: I shall carry out the precepts of the Torah and study her wisdom in order to receive all the blessings written therein or in order to merit the life of the World to Come and I shall keep away from the sins forbidden by the Torah in order to be spared the curses mentioned in the Torah or in order not to be cut off from the life of the World to Come. It is not proper to serve God in this fashion. For one who serves thus serves out of fear. Such a way is not that of the prophets and sages. Only the ignorant, and the women and children serve God in this way. These are trained to serve out of fear until they obtain sufficient knowledge to serve out of love. One who serves God out of love studies the Torah and practices the precepts and walks in the way of wisdom for no ulterior motive at all, neither out of fear of evil nor in order to acquire the good, but follows the truth because it is true and the good will follow the merit of attaining to it. It is the stage of Abraham our father whom the Holy One, blessed be God, called "My friend" (Isaiah 41:8 – ohavi = the one who loves me) because he served out of love alone. It is regarding this stage that the Holy One, Blessed be God, commanded us through Moses, as it is said: "You shall love the Lord your God" (Deuteronomy 6:5). When man loves God with a love that is fitting he automatically carries out all the precepts of love.

(Maimonides Yad Chapter 10, quoted in Jacobs 1973: 159)

The Messiah

Jews believe that a descendant of King David will one day appear to restore the Kingdom of Israel and usher in an era of peace, prosperity, and spiritual understanding for Israel and all the nations of the world. Jews refer to this person as Moshiach or "anointed one", translated as messiah in English. The traditional Jewish understanding of the messiah is that he is fully human and born of human parents without any supernatural element. The messiah is expected to have a relationship with God similar to that of the prophets of the Tanakh. In his commentary on the Talmud, Maimonides (Rabbi Moshe ben Maimon) wrote:

All of the people Israel will come back to Torah; The people of Israel will be gathered back to the land of Israel; The Temple in Jerusalem will be rebuilt; Israel will live among the nations as an equal, and will be strong enough to defend herself; Eventually, war, hatred and famine will end, and an era of peace and prosperity will come upon the Earth.

He adds:

"And if a king shall stand up from among the House of David, studying Torah and indulging in commandments like his father David, according to the written and oral Torah, and he will coerce all Israel to follow it and to strengthen its weak points, and will fight The Lord's wars, this one is to be treated as if he were the anointed one. If he succeeded [and won all nations surrounding him. Old prints and mss.] and built a Holy Temple in its proper place and gathered the strayed ones of Israel together, this is indeed the anointed one for certain, and he will mend the entire world to worship the Lord together ... But if he did not succeed until now, or if he was killed, it becomes known that he is not this one of whom the Torah had promised us, and he is indeed like all [other] proper and wholesome kings of the House of David who died."

He also clarified the nature of the Messiah:

"Do not imagine that the anointed King must perform miracles and signs and create new things in the world or resurrect the dead and so on. The matter is not so: For Rabbi Akiba was a great scholar of the sages of the Mishnah, and he was the assistant-warrior of the king Ben Coziba Simon bar Kokhba... He and all the Sages of his generation deemed him the anointed king, until he was killed by sins; only since he was killed, they knew that he was not. The Sages asked him neither a miracle nor a sign..."

The Christian view of Jesus as Messiah goes beyond such claims and is the fulfillment and union of three anointed offices; a prophet like Moses who delivers God's commands and covenant and frees people from bondage, a High Priest in the order of Melchizedek overshadowing the Levite priesthood and a king like King David ruling over Jews, and like God ruling over the whole world and coming from the line of David.

For Christians, Jesus is also fully human and fully divine as the Word of God who sacrifices himself so that humans can receive salvation. Jesus sits in Heaven at the Right Hand of God and will judge humanity in the end times when he returns to earth.

Christian readings of the Hebrew Bible find many references to Jesus. This can take the form of specific prophesy, and in other cases of foreshadowing by types or forerunners. Traditionally, most Christian readings of the Bible maintained that almost every prophecy was actually about the coming of Jesus, and that the entire Old Testament of the Bible is a prophecy about the coming of Jesus.

Catholic views

Catholicism teaches Extra Ecclesiam Nulla Salus ("Outside the Church there is no salvation"), which some, like Fr. Leonard Feeney, interpreted as limiting salvation to Catholics only. At the same time, it does not deny the possibility that those not visibly members of the Church may attain salvation as well. In recent times, its teaching has been most notably expressed in the Vatican II council documents Unitatis Redintegratio (1964), Lumen gentium (1964), Nostra aetate (1965), an encyclical issued by Pope John Paul II: Ut unum sint (1995), and in a document issued by the Congregation for the Doctrine of the Faith, Dominus Iesus in 2000. The latter document has been criticised for claiming that non-Christians are in a "gravely deficient situation" as compared to Catholics, but also adds that "for those who are not formally and visibly members of the Church, salvation in Christ is accessible by virtue of a grace which, while having a mysterious relationship to the Church, does not make them formally part of the Church, but enlightens them in a way which is accommodated to their spiritual and material situation."

Pope John Paul II on 2 October 2000 emphasized that this document did not say that non-Christians were actively denied salvation: "...this confession does not deny salvation to non-Christians, but points to its ultimate source in Christ, in whom man and God are united". On 6 December the Pope issued a statement to further emphasize that the Church continued to support its traditional stance that salvation was available to believers of other faiths: "The gospel teaches us that those who live in accordance with the Beatitudes—the poor in spirit, the pure of heart, those who bear lovingly the sufferings of life—will enter God's kingdom." He further added, "All who seek God with a sincere heart, including those who do not know Christ and his church, contribute under the influence of Grace to the building of this Kingdom." On 13 August 2002 American Catholic bishops issued a joint statement with leaders of Reform and Conservative Judaism, called "Reflections on Covenant and Mission", which affirmed that Christians should not target Jews for conversion. The document stated: "Jews already dwell in a saving covenant with God" and "Jews are also called by God to prepare the world for God's Kingdom." However, many Christian denominations still believe it is their duty to reach out to "unbelieving" Jews.

In December 2015, the Vatican released a 10,000-word document that, among other things, stated that Jews do not need to be converted to find salvation, and that Catholics should work with Jews to fight antisemitism.

Eastern Orthodox views

Eastern Orthodox Christianity emphasizes a continuing life of repentance or metanoia, which includes an increasing improvement in thought, belief and action. Regarding the salvation of Jews, Muslims, and other non-Christians, the Orthodox have traditionally taught that there is no salvation outside the church. Orthodoxy recognizes that other religions may contain truth, to the extent that they are in agreement with Christianity.

God is thought to be good, just, and merciful; it would not seem just to condemn someone because they never heard the Gospel message, or were taught a distorted version of the Gospel by heretics. Therefore, the reasoning goes, they must at some point have an opportunity to make a genuine informed decision. Ultimately, those who persist in rejecting God condemn themselves, by cutting themselves off from the ultimate source of all Life, and from the God who is Love embodied. Jews, Muslims, and members of other faiths, then, are expected to convert to Christianity in the afterlife.

Proselytizing

Judaism is not a proselytizing religion. Orthodox Judaism deliberately makes it very difficult to convert and become a Jew, and requires a significant and full-time effort in living, study, righteousness, and conduct over several years. The final decision is by no means a foregone conclusion. A person cannot become Jewish by marrying a Jew, or by joining a synagogue, nor by any degree of involvement in the community or religion, but only by explicitly undertaking intense, formal, and supervised work over years aimed towards that goal. Some less strict versions of Judaism have made this process somewhat easier but it is still far from common.

In the past, scholars understood Judaism to have an evangelistic drive, but today's scholars are inclined to the view that it was often more akin just to "greater openness to converts" rather than active soliciting of conversions. Since Jews believe that one need not be a Jew to approach God, there is no religious pressure to convert non-Jews to their faith. Indeed, Scholars have revisited the traditional claims about Jewish proselytizing and have brought forward a variety of new insights. McKnight and Goodman have argued persuasively that a distinction ought to be made between the passive reception of converts or interested Pagans, and an active desire or intent to convert the non-Jewish world to Judaism.

The Chabad-Lubavitch branch of Hasidic Judaism has been an exception to this non-proselytizing standard, since in recent decades it has been actively promoting Noahide Laws for gentiles as an alternative to Christianity.

By contrast, Christianity is an explicitly evangelistic religion. Christians are commanded by Jesus to "Therefore go and make disciples of all nations". Historically, evangelism has on rare occasions led to forced conversion under threat of death or mass expulsion.

Mutual views

Common Jewish views of Christianity

Many Jews view Jesus as one in a long list of failed Jewish claimants to be the Messiah, none of whom fulfilled the tests of a prophet specified in the Law of Moses. Others see Jesus as a teacher who worked with the gentiles and ascribe the messianic claims that Jews find objectionable to his later followers. Because much physical and spiritual violence was done to Jews in the name of Jesus and his followers, and because evangelism is still an active aspect of many churches' activities, many Jews are uncomfortable with discussing Jesus and treat him as a non-person. In answering the question "What do Jews think of Jesus", philosopher Milton Steinberg claims, for Jews, Jesus cannot be accepted as anything more than a teacher. "In only a few respects did Jesus deviate from the Tradition," Steinberg concludes, "and in all of them, Jews believe, he blundered."

Judaism does not believe that God requires the sacrifice of any human. This is emphasized in Jewish traditions concerning the story of the Akedah, the binding of Isaac. In the Jewish explanation, this is a story in the Torah whereby God wanted to test Abraham's faith and willingness, and Isaac was never going to be actually sacrificed. Thus, Judaism rejects the notion that anyone can or should die for anyone else's sin. Judaism is more focused on the practicalities of understanding how one may live a sacred life in the world according to God's will, rather than a hope of a future one. Judaism does not believe in the Christian concept of hell but does have a punishment stage in the afterlife (i.e. Gehenna, a term that also appears in the New Testament and translated as hell) as well as a Heaven (Gan Eden), but the religion does not intend it as a focus.

Judaism views the worship of Jesus as inherently polytheistic, and rejects the Christian attempts to explain the Trinity as a complex monotheism. Christian festivals have no religious significance in Judaism and are not celebrated, but some secular Jews in the West treat Christmas as a secular holiday.

Common Christian views of Judaism

Christians believe that Christianity is the fulfillment and successor of Judaism, retaining much of its doctrine and many of its practices including monotheism, the belief in a Messiah, and certain forms of worship like prayer and reading from religious texts. Christians believe that Judaism requires blood sacrifice to atone for sins, and believe that Judaism has abandoned this since the destruction of the Second Temple. Most Christians consider the Mosaic Law to have been a necessary intermediate stage, but that once the crucifixion of Jesus occurred, adherence to civil and ceremonial Law was superseded by the New Covenant.

Some Christians adhere to New Covenant theology, which states that with the arrival of his New Covenant, Jews have ceased being blessed under his Mosaic covenant. This position has been softened or disputed by other Christians, where Jews are recognized to have a special status under the Abrahamic covenant. New Covenant theology is thus in contrast to Dual-covenant theology.

Some Christians who view the Jewish people as close to God seek to understand and incorporate elements of Jewish understanding or perspective into their beliefs as a means to respect their "parent" religion of Judaism, or to more fully seek out and return to their Christian roots. Christians embracing aspects of Judaism are sometimes criticized as Biblical Judaizers by Christians when they pressure gentile Christians to observe Mosaic teachings rejected by most modern Christians.

Commonwealth Theology (CT) asserts that Judeo-Christian tensions were exacerbated in the fall of Jerusalem and by the subsequent Jewish Revolt. As a result, early Christian theologies formulated in the Roman capitals of Rome and Constantinople began to include antisemitic attitudes, which have been carried forward and embraced by the Protestant Reformers. Dispensation Theology, formalized in the 1830s by John Darby, holds that "God has not rejected His people whom He foreknew." Dispensationalism, however, maintains that God's special dealings with Israel have been interrupted by the Church Age. Commonwealth Theology, on the other hand, recognizes the continuity of God's "congregation in the wilderness" as presently consisting of the Jews (house of Judah) and the Nations (Gentiles), among whom are abiding the historically scattered Northern Kingdom (house of Israel). Commonwealth Theology views the Jews as already included in Commonwealth of Israel even while in unbelief, but nevertheless unsaved in their unbelieving state. CT recognizes that both the reconciliation of the Jewish house and the reconciliation of the estranged house of Israel (among the Gentiles) was accomplished by the cross; and that the salvation of "All Israel" is a process that began on the Day of Pentecost. The full realization of the "one new man" created through the peace (between the Jews and "you Gentiles") made by his cross will take place in Ezekiel's two sticks made one, when both houses of Israel will be united under the Kingdom of David.

Messianic Judaism

Jewish Christians

Some scholars have found evidence of continuous interactions between Jewish-Christian and rabbinic movements from the mid- to late second century CE to the fourth century CE. Of particular importance is the figure of James the brother of Jesus, the leader of the Christian Church in Jerusalem until he was killed in the year 62, who was known for his righteous behavior as a Jew, and set the terms of the relationship between Jewish Christians and Gentile Christians in dialogue with Paul. To him is attributed a letter which emphasizes the view that faith must be expressed in works. The neglect of this mediating figure has often damaged Christian-Jewish relations. Modern scholarship is engaged in an ongoing debate over which term should be used as the proper designation for Jesus' first followers. Many scholars believe that the term Jewish Christians is anachronistic given the fact that there is no consensus on the date of the birth of Christianity. The very concepts of Christianity and Judaism can be seen as essentializing, since these are changing and plural traditions. Clearly, the first Christians would not have believed that they were exchanging one religion for another, because they believed that the resurrection of Jesus was the fulfillment of Jewish prophecies, and they believed that the mission to the gentiles which was initiated by Saul (Paul of Tarsus) was a secondary activity. Some modern scholars have suggested that the designations "Jewish believers in Jesus" and "Jewish followers of Jesus" better reflect the original context.

Inter-faith relationship

Pope Francis praying at the Western Wall in Jerusalem on his 2014 visit to the Holy Land.

In addition to Christianity and Judaism's varying views on each other as religions, there has also been a long and often painful history of conflict, persecution and at times, reconciliation, between the two religions, which have influenced their mutual views of their relationship with each other over time. Since the end of the Second World War and The Holocaust, Christianity has embarked on a process of introspection with regard to its Jewish roots and its attitudes toward Judaism. The eradication of the anti-Jewish tendencies is but one dimension of this ongoing Christian introspection, that attempts to engage a variety of legacies that disturb modern believers (Antisemitism, slavery, racial and ethnic prejudice, colonialism, sexism, homophobia and religious persecution).

Since the Middle Ages, the Catholic Church upheld Constitutio pro Judæis (Formal Statement on the Jews), which stated

We decree that no Christian shall use violence to force them to be baptized, so long as they are unwilling and refuse. ... Without the judgment of the political authority of the land, no Christian shall presume to wound them or kill them or rob them of their money or change the good customs that they have thus far enjoyed in the place where they live."

Persecution, forcible conversion, and forcible displacement of Jews (i.e. hate crimes) occurred for many centuries, along with occasional gestures at reconciliation which also occurred from time to time. Pogroms were a common occurrence throughout Christian Europe, including organized violence, restrictive land ownership and professional lives, forcible relocation and ghettoization, mandatory dress codes, and at times, humiliating actions and torture. All of these actions and restrictions had major effects on Jewish cultures. From the fifth century onward, Church councils imposed ever-increasing burdens and limitations on the Jews. Among the decrees: marriages between a Jew and a Christian were forbidden ( Orleans, 533 and 538; Clermont, 535; Toledo, 589 and 633). Jews and Christians forbidden to eat together (Vannes, 465; Agde, 506; Epaone, 517; Orleans, 538; Macon, 583; Clichy, 626–7). Jews banned from public office ( Clermont, 535; Toledo, 589; Paris, 614–5; Clichy, 626–7; Toledo, 633). Jews were forbidden to appear in public during Easter ( Orleans, 538; Macon, 583) and to work on Sunday (Narbonne, 589). By the end of the first millennium, the Jewish population in the Christian lands had been decimated, expelled, forced into conversion or worse. Only a few small and scattered communities survived.

There have also been non-coercive outreach and missionary efforts such as the Church of England's Ministry Among Jewish People, founded in 1809.

For Martin Buber, Judaism and Christianity were variations on the same theme of messianism. Buber made this theme the basis of a famous definition of the tension between Judaism and Christianity:

Pre-messianically, our destinies are divided. Now to the Christian, the Jew is the incomprehensibly obdurate man who declines to see what has happened; and to the Jew, the Christian is the incomprehensibly daring man who affirms in an unredeemed world that its redemption has been accomplished. This is a gulf which no human power can bridge.

The Nazi Party was known for its persecution of Christian Churches; many of them, such as the Protestant Confessing Church and the Catholic Church, as well as Quakers and Jehovah's Witnesses, aided and rescued Jews who were being targeted by the régime.

Following the Holocaust, attempts have been made to construct a new Jewish-Christian relationship of mutual respect for differences, through the inauguration of the interfaith body the Council of Christians and Jews in 1942 and International Council of Christians and Jews. The Seelisberg Conference in 1947 established 10 points relating to the sources of Christian antisemitism. The ICCJ's "Twelve points of Berlin" sixty years later aim to reflect a recommitment to interreligious dialogue between the two communities.

Pope John Paul II and the Catholic Church have "upheld the Church's acceptance of the continuing and permanent election of the Jewish people" as well as a reaffirmation of the covenant between God and the Jews. In December 2015, the Vatican released a 10,000-word document that, among other things, stated that Catholics should work with Jews to fight antisemitism.

Orthodox Rabbinic Statement on Christianity

In 2012, the book Kosher Jesus by Orthodox Rabbi Shmuley Boteach was published. In it, he takes the position that Jesus was a wise and learned Torah-observant Jewish rabbi. Boteach says he was a beloved member of the Jewish community. At the same time, Jesus is said to have despised the Romans for their cruelty, and fought them courageously. The book states that the Jews had nothing whatsoever to do with the murder of Jesus, but rather that blame for his trial and killing lies with the Romans and Pontius Pilate. Boteach states clearly that he does not believe in Jesus as the Jewish Messiah. At the same time, Boteach argues that "Jews have much to learn from Jesus - and from Christianity as a whole - without accepting Jesus' divinity. There are many reasons for accepting Jesus as a man of great wisdom, beautiful ethical teachings, and profound Jewish patriotism." He concludes by writing, as to Judeo-Christian values, that "the hyphen between Jewish and Christian values is Jesus himself."

On 3 December 2015, the Center for Jewish-Christian Understanding and Cooperation (CJCUC) spearheaded a petition of Orthodox rabbis from around the world calling for increased partnership between Jews and Christians. The unprecedented Orthodox Rabbinic Statement on Christianity, entitled "To Do the Will of Our Father in Heaven: Toward a Partnership between Jews and Christians", was initially signed by over 25 prominent Orthodox rabbis in Israel, the United States, and Europe, and as of 2016 had over 60 signatories.

Between Jerusalem and Rome

On 31 August 2017, representatives of the Conference of European Rabbis, the Rabbinical Council of America, and the Commission of the Chief Rabbinate of Israel issued and presented the Holy See with a statement entitled Between Jerusalem and Rome. The document pays particular tribute to the Second Vatican Council's Declaration Nostra Aetate, whose fourth chapter represents the "Magna Carta" of the Holy See's dialogue with the Jewish world. The Statement Between Jerusalem and Rome does not hide the theological differences that exist between the two faith traditions while all the same it expresses a firm resolve to collaborate more closely, now and in the future.

Ontology

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Ontology
An illustration of Cartesian materialism, which argues that it is possible to find the content of conscious experience moment by moment in the mind. Materialism in general, arguing that matter is the fundamental 'substance', is an influential perspective on ontology.

In metaphysics, ontology is the philosophical study of being. It investigates what types of entities exist, how they are grouped into categories, and how they are related to one another on the most fundamental level. Ontologists often try to determine what the categories or highest kinds are and how they form a system of categories that encompasses the classification of all entities. Commonly proposed categories include substances, properties, relations, states of affairs, and events. These categories are characterized by fundamental ontological concepts, including particularity and universality, abstractness and concreteness, or possibility and necessity. Of special interest is the concept of ontological dependence, which determines whether the entities of a category exist on the most fundamental level. Disagreements within ontology are often about whether entities belonging to a certain category exist and, if so, how they are related to other entities.

When used as a countable noun, the words ontology and ontologies refer not to the science of being but to theories within the science of being. Ontological theories can be divided into various types according to their theoretical commitments. Monocategorical ontologies hold that there is only one basic category, but polycategorical ontologies rejected this view. Hierarchical ontologies assert that some entities exist on a more fundamental level and that other entities depend on them. Flat ontologies, on the other hand, deny such a privileged status to any entity.

Etymology

The compound word ontology ('study of being') combines

onto- (Greek: ὄν, on; GEN. ὄντος, ontos, 'being' or 'that which is') and
-logia (-λογία, 'logical discourse').

While the etymology is Greek, the oldest extant records of the word itself is a Neo-Latin form ontologia, which appeared

in 1606 in the Ogdoas Scholastica by Jacob Lorhard (Lorhardus), and
in 1613 in the Lexicon philosophicum by Rudolf Göckel (Goclenius).

The first occurrence in English of ontology, as recorded by the Oxford English Dictionary, came in 1664 through Archelogia philosophica nova... by Gideon Harvey. The word was first used, in its Latin form, by philosophers, and based on the Latin roots (and in turn on the Greek ones).

Overview

Ontology is closely associated with Aristotle's question of 'being qua being': the question of what all entities in the widest sense have in common. The Eleatic principle is one answer to this question: it states that being is inextricably tied to causation, that "Power is the mark of Being". One problem with this answer is that it excludes abstract objects. Another explicit but little accepted answer can be found in Berkeley's slogan that "to be is to be perceived". Intimately related but not identical to the question of 'being qua being' is the problem of categories. Categories are usually seen as the highest kinds or genera. A system of categories provides a classification of entities that is exclusive and exhaustive: every entity belongs to exactly one category. Various such classifications have been proposed, they often include categories for substances, properties, relations, states of affairs or events. At the core of the differentiation between categories are various fundamental ontological concepts and distinctions, for example, the concepts of particularity and universality, of abstractness and concreteness, of ontological dependence, of identity and of modality. These concepts are sometimes treated as categories themselves, are used to explain the difference between categories or play other central roles for characterizing different ontological theories. Within ontology, there is a lack of general consensus concerning how the different categories are to be defined. Different ontologists often disagree on whether a certain category has any members at all or whether a given category is fundamental.

Particulars and universals

Particulars or individuals are usually contrasted with universals. Universals concern features that can be exemplified by various different particulars. For example, a tomato and a strawberry are two particulars that exemplify the universal redness. Universals can be present at various distinct locations in space at the same time while particulars are restricted to one location at a time. Furthermore, universals can be fully present at different times, which is why they are sometimes referred to as repeatables in contrast to non-repeatable particulars. The so-called problem of universals is the problem to explain how different things can agree in their features, e.g. how a tomato and a strawberry can both be red. Realists believe that there are universals. They can solve the problem of universals by explaining the commonality through a universal shared by both entities. Realists are divided among themselves as to whether universals can exist independently of being exemplified by something ("ante res") or not ("in rebus"). Nominalists, on the other hand, deny that there are universals. They have to resort to other notions to explain how a feature can be common to several entities, for example, by positing either fundamental resemblance-relations between the entities (resemblance nominalism) or a shared membership to a common natural class (class nominalism).

Abstract and concrete

Many philosophers agree that there is an exclusive and exhaustive distinction between concrete objects and abstract objects. Some philosophers consider this to be the most general division of being. Examples of concrete objects include plants, human beings and planets while things like numbers, sets and propositions are abstract objects. But despite the general agreement concerning the paradigm cases, there is less consensus as to what the characteristic marks of concreteness and abstractness are. Popular suggestions include defining the distinction in terms of the difference between (1) existence inside or outside space-time, (2) having causes and effects or not and (3) having contingent or necessary existence.

Ontological dependence

An entity ontologically depends on another entity if the first entity cannot exist without the second entity. Ontologically independent entities, on the other hand, can exist all by themselves. For example, the surface of an apple cannot exist without the apple and so depends on it ontologically. Entities often characterized as ontologically dependent include properties, which depend on their bearers, and boundaries, which depend on the entity they demarcate from its surroundings. As these examples suggest, ontological dependence is to be distinguished from causal dependence, in which an effect depends for its existence on a cause. It is often important to draw a distinction between two types of ontological dependence: rigid and generic. Rigid dependence concerns the dependence on one specific entity, as the surface of an apple depends on its specific apple. Generic dependence, on the other hand, involves a weaker form of dependence, on merely a certain type of entity. For example, electricity generically depends on there being charged particles, but it does not depend on any specific charged particle. Dependence-relations are relevant to ontology since it is often held that ontologically dependent entities have a less robust form of being. This way a hierarchy is introduced into the world that brings with it the distinction between more and less fundamental entities.

Identity

Identity is a basic ontological concept that is often expressed by the word "same". It is important to distinguish between qualitative identity and numerical identity. For example, consider two children with identical bicycles engaged in a race while their mother is watching. The two children have the same bicycle in one sense (qualitative identity) and the same mother in another sense (numerical identity). Two qualitatively identical things are often said to be indiscernible. The two senses of sameness are linked by two principles: the principle of indiscernibility of identicals and the principle of identity of indiscernibles. The principle of indiscernibility of identicals is uncontroversial and states that if two entities are numerically identical with each other then they exactly resemble each other. The principle of identity of indiscernibles, on the other hand, is more controversial in making the converse claim that if two entities exactly resemble each other then they must be numerically identical. This entails that "no two distinct things exactly resemble each other". A well-known counterexample comes from Max Black, who describes a symmetrical universe consisting of only two spheres with the same features. Black argues that the two spheres are indiscernible but not identical, thereby constituting a violation of the principle of identity of indiscernibles.

The problem of identity over time concerns the question of persistence: whether or in what sense two objects at different times can be numerically identical. This is usually referred to as diachronic identity in contrast to synchronic identity. The statement that "[t]he table in the next room is identical with the one you purchased last year" asserts diachronic identity between the table now and the table then. A famous example of a denial of diachronic identity comes from Heraclitus, who argues that it is impossible to step into the same river twice because of the changes that occurred in-between. The traditional position on the problem of persistence is endurantism, the thesis that diachronic identity in a strict sense is possible. One problem with this position is that it seems to violate the principle of indiscernibility of identicals: the object may have undergone changes in the meantime resulting in it being discernible from itself. Perdurantism or four-dimensionalism is an alternative approach holding that diachronic identity is possible only in a loose sense: while the two objects differ from each other strictly speaking, they are both temporal parts that belong to the same temporally extended whole. Perdurantism avoids many philosophical problems plaguing endurantism, but endurantism seems to be more in touch with how we ordinarily conceive diachronic identity.

Modality

Modality concerns the concepts of possibility, actuality and necessity. In contemporary discourse, these concepts are often defined in terms of possible worlds. A possible world is a complete way how things could have been. The actual world is one possible world among others: things could have been different from what they actually are. A proposition is possibly true if there is at least one possible world in which it is true; it is necessarily true if it is true in all possible worlds. Actualists and possibilists disagree on the ontological status of possible worlds. Actualists hold that reality is at its core actual and that possible worlds should be understood in terms of actual entities, for example, as fictions or as sets of sentences. Possibilists, on the other hand, assign to possible worlds the same fundamental ontological status as to the actual world. This is a form of modal realism, holding that reality has irreducibly modal features. Another important issue in this field concerns the distinction between contingent and necessary beings. Contingent beings are beings whose existence is possible but not necessary. Necessary beings, on the other hand, could not have failed to exist. It has been suggested that this distinction is the highest division of being.

Substances

The category of substances has played a central role in many ontological theories throughout the history of philosophy. "Substance" is a technical term within philosophy not to be confused with the more common usage in the sense of chemical substances like gold or sulfur. Various definitions have been given but among the most common features ascribed to substances in the philosophical sense is that they are particulars that are ontologically independent: they are able to exist all by themselves. Being ontologically independent, substances can play the role of fundamental entities in the ontological hierarchy. If 'ontological independence' is defined as including causal independence then only self-caused entities, like Spinoza's God, can be substances. With a specifically ontological definition of 'independence', many everyday objects like books or cats may qualify as substances. Another defining feature often attributed to substances is their ability to undergo changes. Changes involve something existing before, during and after the change. They can be described in terms of a persisting substance gaining or losing properties, or of matter changing its form. From this perspective, the ripening of a tomato may be described as a change in which the tomato loses its greenness and gains its redness. It is sometimes held that a substance can have a property in two ways: essentially and accidentally. A substance can survive a change of accidental properties but it cannot lose its essential properties, which constitute its nature.

Properties and relations

The category of properties consists of entities that can be exemplified by other entities, e.g. by substances. Properties characterize their bearers, they express what their bearer is like. For example, the red color and the round shape of an apple are properties of this apple. Various ways have been suggested concerning how to conceive properties themselves and their relation to substances. The traditionally dominant view is that properties are universals that inhere in their bearers. As universals, they can be shared by different substances. Nominalists, on the other hand, deny that universals exist. Some nominalists try to account for properties in terms of resemblance relations or class membership. Another alternative for nominalists is to conceptualize properties as simple particulars, so-called tropes. This position entails that both the apple and its redness are particulars. Different apples may still exactly resemble each other concerning their color, but they do not share the same particular property on this view: the two color-tropes are numerically distinct. Another important question for any theory of properties is how to conceive the relation between a bearer and its properties. Substratum theorists hold that there is some kind of substance, substratum or bare particular that acts as bearer. Bundle theory is an alternative view that does away with a substratum altogether: objects are taken to be just a bundle of properties. They are held together not by a substratum but by the so-called compresence-relation responsible for the bundling. Both substratum theory and bundle theory can be combined with conceptualizing properties as universals or as particulars.

An important distinction among properties is between categorical and dispositional properties. Categorical properties concern what something is like, e.g. what qualities it has. Dispositional properties, on the other hand, involve what powers something has, what it is able to do, even if it is not actually doing it. For example, the shape of a sugar cube is a categorical property while its tendency to dissolve in water is a dispositional property. For many properties there is a lack of consensus as to how they should be classified, for example, whether colors are categorical or dispositional properties. Categoricalism is the thesis that on a fundamental level there are only categorical properties, that dispositional properties are either non-existent or dependent on categorical properties. Dispositionalism is the opposite theory, giving ontological primacy to dispositional properties. Between these two extremes, there are dualists who allow both categorical and dispositional properties in their ontology.

Relations are ways in which things, the relata, stand to each other. Relations are in many ways similar to properties in that both characterize the things they apply to. Properties are sometimes treated as a special case of relations involving only one relatum. Central for ontology is the distinction between internal and external relations. A relation is internal if it is fully determined by the features of its relata. For example, an apple and a tomato stand in the internal relation of similarity to each other because they are both red. Some philosophers have inferred from this that internal relations do not have a proper ontological status since they can be reduced to intrinsic properties. External relations, on the other hand, are not fixed by the features of their relata. For example, a book stands in an external relation to a table by lying on top of it. But this is not determined by the book's or the table's features like their color, their shape, etc.

States of affairs and events

States of affairs are complex entities, in contrast to substances and properties, which are usually conceived as simple. Complex entities are built up from or constituted by other entities. Atomic states of affairs are constituted by one particular and one property exemplified by this particular. For example, the state of affairs that Socrates is wise is constituted by the particular "Socrates" and the property "wise". Relational states of affairs involve several particulars and a relation connecting them. States of affairs that obtain are also referred to as facts. It is controversial which ontological status should be ascribed to states of affairs that do not obtain. States of affairs have been prominent in 20th-century ontology as various theories were proposed to describe the world as composed of states of affairs. It is often held that states of affairs play the role of truthmakers: judgments or assertions are true because the corresponding state of affairs obtains.

Events take place in time, they are sometimes thought of as involving a change in the form of acquiring or losing a property, like the lawn's becoming dry. But on a liberal view, the retaining of a property without any change may also count as an event, e.g. the lawn's staying wet. Some philosophers see events as universals that can repeat at different times, but the more dominant view is that events are particulars and therefore non-repeatable. Some events are complex in that they are composed of a sequence of events, often referred to as a process. But even simple events can be conceived as complex entities involving an object, a time and the property exemplified by the object at this time. So-called process philosophy or process ontology ascribes ontological primacy to changes and processes as opposed to the emphasis on static being in the traditionally dominant substance metaphysics.

Reality of things

The word 'real' is derived from the Latin word res, which is often translated as 'thing'. The word 'thing' is often used in ontological discourse as if it had a presupposed meaning, not needing an explicit philosophical definition because it belongs to ordinary language. Nevertheless, what is a thing and what is real or substantial are concerns of ontology. Different views are held about this. Plato proposed that underlying, and constituting the real basis of, the concretely experienced world are 'forms' or 'ideas', which today are generally regarded as high abstractions. In earlier days, philosophers used the term 'realism' to refer to Plato's belief that his 'forms' are 'real'; nowadays, the term 'realism' often has an almost opposite meaning, so that Plato's belief is sometimes called 'idealism'. Philosophers debate whether entities such as tables and chairs, lions and tigers, philosophical doctrines, numbers, truth, and beauty, are to be regarded as 'things', or as something or nothing 'real'.

Types of ontologies

Ontological theories can be divided into various types according to their theoretical commitments. Particular ontological theories or types of theories are often referred to as "ontologies" (singular or plural). This usage contrasts with the meaning of "ontology" (only singular) as a branch of philosophy: the science of being in general.

Flat vs polycategorical vs hierarchical

One way to divide ontologies is by the number of basic categories they use. Monocategorical or one category ontologies hold that there is only one basic category while polycategorical ontologies imply that there are several distinct basic categories. Another way to divide ontologies is through the notion of ontological hierarchy. Hierarchical ontologies assert that some entities exist on a more fundamental level and that other entities depend on them. Flat ontologies, on the other hand, deny such a privileged status to any entities. Jonathan Schaffer provides an overview of these positions by distinguishing between flat ontologies (non-hierarchical), sorted ontologies (polycategorical non-hierarchical) and ordered ontologies (polycategorical hierarchical).

Flat ontologies are only interested in the difference between existence and non-existence. They are flat because each flat ontology can be represented by a simple set containing all the entities to which this ontology is committed. An influential exposition of this approach comes from Willard Van Orman Quine which is why it has been referred to as the Quinean approach to meta-ontology. This outlook does not deny that the existing entities can be further subdivided and may stand in various relations to each other. These issues are questions for the more specific sciences, but they do not belong to ontology in the Quinean sense.

Polycategorical ontologies are concerned with the categories of being. Each polycategorical ontology posits a number of categories. These categories are exclusive and exhaustive: every existing entity belongs to exactly one category. A recent example of a polycategorical ontology is E.J. Lowe's four-category-ontology. The four categories are object, kind, mode and attribute. The fourfold structure is based on two distinctions. The first distinction is between substantial entities (objects and kinds) and non-substantial entities (modes and attributes). The second distinction is between particular entities (objects and modes) and universal entities (kinds and attributes). Reality is built up through the interplay of entities belonging to different categories: particular entities instantiate universal entities, and non-substantial entities characterize substantial entities.

Hierarchical ontologies are interested in the degree of fundamentality of the entities they posit. Their main goal is to figure out which entities are fundamental and how the non-fundamental entities depend on them. The concept of fundamentality is usually defined in terms of metaphysical grounding. Fundamental entities are different from non-fundamental entities because they are not grounded in other entities. For example, it is sometimes held that elementary particles are more fundamental than the macroscopic objects (like chairs and tables) they compose. This is a claim about the grounding-relation between microscopic and macroscopic objects. Schaffer's priority monism is a recent form of a hierarchical ontology. He holds that on the most fundamental level there exists only one thing: the world as a whole. This thesis does not deny our common-sense intuition that the distinct objects we encounter in our everyday affairs like cars or other people exist. It only denies that these objects have the most fundamental form of existence. An example of a hierarchical ontology in continental philosophy comes from Nicolai Hartmann. He asserts that reality is made up of four levels: the inanimate, the biological, the psychological and the spiritual. These levels form a hierarchy in the sense that the higher levels depend on the lower levels while the lower levels are indifferent to the higher levels.

Thing ontologies vs fact ontologies

Thing ontologies and fact ontologies are one-category-ontologies: they both hold that all fundamental entities belong to the same category. They disagree on whether this category is the category of things or of facts. A slogan for fact ontologies comes from Ludwig Wittgenstein: "The world is the totality of facts, not of things".

One difficulty in characterizing this dispute is to elucidate what things and facts are, and how they differ from each other. Things are commonly contrasted with the properties and relations they instantiate. Facts, on the other hand, are often characterized as having these things and the properties/relations as their constituents. This is reflected in a rough linguistic characterization of this difference where the subjects and objects of an assertion refer to things while the assertion as a whole refers to a fact.

Reism is one form of thing ontology. Franz Brentano developed a version of reism in his later philosophy. He held that only concrete particular things exist. Things can exist in two forms: either as spatio-temporal bodies or as temporal souls. Brentano was aware of the fact that many common-sense expressions seem to refer to entities that do not have a place in his ontology, like properties or intentional objects. This is why he developed a method to paraphrase these expressions in order to avoid these ontological commitments.

D. M. Armstrong is a well-known defender of fact ontology. He and his followers refer to facts as states of affairs. States of affairs are the basic building blocks of his ontology: they have particulars and universals as their constituents but they are primary in relation to particulars and universals. States of affairs have ontologically independent existence while "[u]npropertied particulars and uninstantiated universals are false abstractions".

Constituent ontologies vs blob theories

Constituent ontologies and blob theories, sometimes referred to as relational ontologies, are concerned with the internal structure of objects. Constituent ontologies hold that objects have an internal structure made up of constituents. This is denied by blob theories: they contend that objects are structureless "blobs".

Bundle theories are examples of constituent ontologies. Bundle theorists assert that an object is nothing but the properties it "has". On this account, a regular apple could be characterized as a bundle of redness, roundness, sweetness, etc. Defenders of bundle theory disagree on the nature of the bundled properties. Some affirm that these properties are universals while others contend that they are particulars, so-called "tropes".

Class nominalism, on the other hand, is a form of blob theory. Class nominalists hold that properties are classes of things. To instantiate a property is merely to be a member of the corresponding class. So properties are not constituents of the objects that have them.

Information science and natural sciences

In information science ontologies are classified in various ways, using criteria such as the degree of abstraction and field of application:

  1. Upper ontology: concepts supporting development of an ontology, meta-ontology.
  2. Domain ontology: concepts relevant to a particular topic, domain of discourse, or area of interest, for example, to information technology or to computer languages, or to particular branches of science.
  3. Interface ontology: concepts relevant to the juncture of two disciplines.
  4. Process ontology: inputs, outputs, constraints, sequencing information, involved in business or engineering processes.

In the biomedical sciences, ontologies have been used to create terminologies for various aspects of living organism or medical applications. A prominent example is the gene ontology, but many other ontologies exist, e.g. for anatomical terms or physiology. Standards have been established to maintain and organize biological ontologies under the OBO (Open Biological Ontologies) project.

History

Ancient Greek

Parmenides was among the first to propose an ontological characterization of the fundamental nature of reality.

In the Greek philosophical tradition, Parmenides was among the first to propose an ontological characterization of the fundamental nature of existence. In the prologue (or proem) to On Nature, he describes two views of existence. Initially, nothing comes from nothing, thus existence is eternal. This posits that existence is what may be conceived of by thought, created, or possessed. Hence, there may be neither void nor vacuum; and true reality neither may come into being nor vanish from existence. Rather, the entirety of creation is eternal, uniform, and immutable, though not infinite (Parmenides characterized its shape as that of a perfect sphere). Parmenides thus posits that change, as perceived in everyday experience, is illusory.

Opposite to the Eleatic monism of Parmenides is the pluralistic conception of being. In the 5th century BC, Anaxagoras and Leucippus replaced the reality of being (unique and unchanging) with that of becoming, therefore by a more fundamental and elementary ontic plurality. This thesis originated in the Hellenic world, stated in two different ways by Anaxagoras and by Leucippus. The first theory dealt with "seeds" (which Aristotle referred to as "homeomeries") of the various substances. The second was the atomistic theory, which dealt with reality as based on the vacuum, the atoms and their intrinsic movement in it.

The materialist atomism proposed by Leucippus was indeterminist, but Democritus (c. 460 – c. 370 BC) subsequently developed it in a deterministic way. Later (4th century BC), Epicurus took the original atomism again as indeterministic. He saw reality as composed of an infinity of indivisible, unchangeable corpuscles or atoms (from the Greek atomon, lit. 'uncuttable'), but he gives weight to characterize atoms whereas for Leucippus they are characterized by a "figure", an "order" and a "position" in the cosmos. Atoms are, besides, creating the whole with the intrinsic movement in the vacuum, producing the diverse flux of being. Their movement is influenced by the parenklisis (Lucretius names it clinamen) and that is determined by chance. These ideas foreshadowed the understanding of traditional physics until the advent of 20th-century theories on the nature of atoms.

Plato developed the distinction between true reality and illusion, in arguing that what is real are eternal and unchanging forms or ideas (a precursor to universals), of which things experienced in sensation are at best merely copies, and real only in so far as they copy ("partake of") such forms. In general, Plato presumes that all nouns (e.g., "beauty") refer to real entities, whether sensible bodies or insensible forms. Hence, in The Sophist, Plato argues that being is a form in which all existent things participate and which they have in common (though it is unclear whether "Being" is intended in the sense of existence, copula, or identity); and argues, against Parmenides, that forms must exist not only of being, but also of Negation and of non-being (or Difference).

In his Categories, Aristotle (384–322 BCE) identifies ten possible kinds of things that may be the subject or the predicate of a proposition. For Aristotle there are four different ontological dimensions:

  1. according to the various categories or ways of addressing a being as such
  2. according to its truth or falsity (e.g. fake gold, counterfeit money)
  3. whether it exists in and of itself or simply 'comes along' by accident
  4. according to its potency, movement (energy) or finished presence (Metaphysics Book Theta).

Hindu philosophy

Ontology features in the Samkhya school of Hindu philosophy from the first millennium BCE. Samkhya philosophy regards the universe as consisting of two independent realities: puruṣa (pure, contentless consciousness) and prakṛti (matter). The substance dualism between puruṣa and prakṛti is similar but not identical to the substance dualism between mind and body that, following the works of Descartes, has been central to many disputes in the Western philosophical tradition. Samkhya sees the mind as being the subtle part of prakṛti. It is made up of three faculties: the sense mind (manas), the intellect (buddhi), and the ego (ahaṁkāra). These faculties perform various functions but are by themselves unable to produce consciousness, which belongs to a distinct ontological category and for which puruṣa alone is responsible. The Yoga school agrees with Samkhya philosophy on the fundamental dualism between puruṣa and prakṛti but it differs from Samkhya's atheistic position by incorporating the concept of a "personal, yet essentially inactive, deity" or "personal god" (Ishvara). These two schools stand in contrast to Advaita Vedanta, which adheres to non-duality by revealing that the apparent plurality of things is an illusion (Maya) hiding the true oneness of reality at its most fundamental level (Brahman).

Medieval

Medieval ontology was strongly influenced by Aristotle's teachings. The thinkers of this period often relied on Aristotelian categories like substance, act and potency or matter and form to formulate their own theories. Important ontologists in this epoch include Avicenna, Thomas Aquinas, Duns Scotus and William of Ockham.

According to Avicenna's interpretation of Greek Aristotelian and Platonist ontological doctrines in medieval metaphysics, being is either necessary, contingent qua possible, or impossible. Necessary being is that which cannot but be, since its non-being would entail a contradiction. Contingent qua possible being is neither necessary nor impossible for it to be or not to be. It is ontologically neutral, and is brought from potential existing into actual existence by way of a cause that is external to its essence. Its being is borrowed – unlike the necessary existent, which is self-subsisting and impossible not to be. As for the impossible, it necessarily does not exist, and the affirmation of its being would involve a contradiction.

Fundamental to Thomas Aquinas's ontology is his distinction between essence and existence: all entities are conceived as composites of essence and existence. The essence of a thing is what this thing is like, it signifies the definition of this thing. God has a special status since He is the only entity whose essence is identical to its existence. But for all other, finite entities there is a real distinction between essence and existence. This distinction shows itself, for example, in our ability to understand the essence of something without knowing about its existence. Aquinas conceives of existence as an act of being that actualizes the potency given by the essence. Different things have different essences, which impose different limits on the corresponding act of being. The paradigm examples of essence-existence-composites are material substances like cats or trees. Aquinas incorporates Aristotle's distinction between matter and form by holding that the essence of material things, as opposed to the essence of immaterial things like angels, is the composition of their matter and form. So, for example, the essence of a marble statue would be the composition of the marble (its matter) and the shape it has (its form). Form is universal since substances made of different matter can have the same form. The forms of a substance may be divided into substantial and accidental forms. A substance can survive a change of an accidental form but ceases to exist upon a change of a substantial form.

Modern

Ontology is increasingly seen as a separate domain of philosophy in the modern period. Many ontological theories of this period were rationalistic in the sense that they saw ontology largely as a deductive discipline that starts from a small set of first principles or axioms, a position best exemplified by Baruch Spinoza and Christian Wolff. This rationalism in metaphysics and ontology was strongly opposed by Immanuel Kant, who insisted that many claims arrived at this way are to be dismissed since they go beyond any possible experience that could justify them.

René Descartes' ontological distinction between mind and body has been one of the most influential parts of his philosophy. On his view, minds are thinking things while bodies are extended things. Thought and extension are two attributes that each come in various modes of being. Modes of thinking include judgments, doubts, volitions, sensations and emotions while the shapes of material things are modes of extension. Modes come with a lower degree of reality since they depend for their existence on a substance. Substances, on the other hand, can exist on their own. Descartes' substance dualism asserts that every finite substance is either a thinking substance or an extended substance. This position does not entail that minds and bodies actually are separated from each other, which would defy the intuition that we both have a body and a mind. Instead, it implies that minds and bodies can, at least in principle, be separated, since they are distinct substances and therefore are capable of independent existence. A longstanding problem for substance dualism since its inception has been to explain how minds and bodies can causally interact with each other, as they apparently do, when a volition causes an arm to move or when light falling on the retina causes a visual impression.

Baruch Spinoza is well-known for his substance monism: the thesis that only one substance exists. He refers to this substance as "God or Nature", emphasizing both his pantheism and his naturalism. This substance has an infinite amount of attributes, which he defines as "what the intellect perceives of substance as constituting its essence". Of these attributes, only two are accessible to the human mind: thought and extension. Modes are properties of a substance that follow from its attributes and therefore have only a dependent form of existence. Spinoza sees everyday-things like rocks, cats or ourselves as mere modes and thereby opposes the traditional Aristotelian and Cartesian conception of categorizing them as substances. Modes compose deterministic systems in which the different modes are linked to each other as cause and effect. Each deterministic system corresponds to one attribute: one for extended things, one for thinking things, etc. Causal relations only happen within a system while the different systems run in parallel without causally interacting with each other. Spinoza calls the system of modes Natura naturata ("nature natured") and opposes it to Natura naturans ("nature naturing"), the attributes responsible for the modes. Everything in Spinoza's system is necessary: there are no contingent entities. This is so since the attributes are themselves necessary and since the system of modes follows from them.

Christian Wolff defines ontology as the science of being in general. He sees it as a part of metaphysics besides cosmology, psychology and natural theology. According to Wolff, it is a deductive science, knowable a priori and based on two fundamental principles: the principle of non-contradiction ("it cannot happen that the same thing is and is not") and the principle of sufficient reason ("nothing exists without a sufficient reason for why it exists rather than does not exist"). Beings are defined by their determinations or predicates, which cannot involve a contradiction. Determinates come in 3 types: essentialia, attributes, and modes. Essentialia define the nature of a being and are therefore necessary properties of this being. Attributes are determinations that follow from essentialia and are equally necessary, in contrast to modes, which are merely contingent. Wolff conceives existence as just one determination among others, which a being may lack. Ontology is interested in being at large, not just in actual being. But all beings, whether actually existing or not, have a sufficient reason. The sufficient reason for things without actual existence consists in all the determinations that make up the essential nature of this thing. Wolff refers to this as a "reason of being" and contrasts it with a "reason of becoming", which explains why some things have actual existence.

Arthur Schopenhauer was a proponent of metaphysical voluntarism: he regards will as the underlying and ultimate reality. Reality as a whole consists only of one will, which is equated with the Kantian thing-in-itself. Like the Kantian thing-in-itself, the will exists outside space and time. But, unlike the Kantian thing-in-itself, the will has an experiential component to it: it comes in the form of striving, desiring, feeling, etc. The manifold of things we encounter in our everyday experiences, like trees or cars, are mere appearances that lack existence independent of the observer. Schopenhauer describes them as objectivations of the will. These objectivations happen in different "steps", which correspond to the platonic forms. All objectivations are grounded in the will. This grounding is governed by the principium individuationis, which enables a manifold of individual things spread out in space and time to be grounded in the one will.

20th century

Dominant approaches to ontology in the 20th century were phenomenology, linguistic analysis and naturalism. Phenomenological ontology, as exemplified by Edmund Husserl and Martin Heidegger, relies for its method on the description of experience. Linguistic analysis assigns to language a central role for ontology, as seen, for example, in Rudolf Carnap's thesis that the truth value of existence-claims depends on the linguistic framework in which they are made. Naturalism gives a prominent position to the natural sciences for the purpose of finding and evaluating ontological claims. This position is exemplified by Quine's method of ontology, which involves analyzing the ontological commitments of scientific theories.

Edmund Husserl sees ontology as a science of essences. Sciences of essences are contrasted with factual sciences: the former are knowable a priori and provide the foundation for the later, which are knowable a posteriori. Ontology as a science of essences is not interested in actual facts, but in the essences themselves, whether they have instances or not. Husserl distinguishes between formal ontology, which investigates the essence of objectivity in general, and regional ontologies, which study regional essences that are shared by all entities belonging to the region. Regions correspond to the highest genera of concrete entities: material nature, personal consciousness and interpersonal spirit. Husserl's method for studying ontology and sciences of essence in general is called eidetic variation. It involves imagining an object of the kind under investigation and varying its features. The changed feature is inessential to this kind if the object can survive its change, otherwise it belongs to the kind's essence. For example, a triangle remains a triangle if one of its sides is extended but it ceases to be a triangle if a fourth side is added. Regional ontology involves applying this method to the essences corresponding to the highest genera.

Central to Martin Heidegger's philosophy is the notion of ontological difference: the difference between being as such and specific entities. He accuses the philosophical tradition of being forgetful of this distinction, which has led to the mistake of understanding being as such as a kind of ultimate entity, for example as "idea, energeia, substance, monad or will to power". Heidegger tries to rectify this mistake in his own "fundamental ontology" by focusing on the meaning of being instead, a project which is akin to contemporary meta-ontology. One method to achieve this is by studying the human being, or Dasein, in Heidegger's terminology. The reason for this is that we already have a pre-ontological understanding of being that shapes how we experience the world. Phenomenology can be used to make this implicit understanding explicit, but it has to be accompanied by hermeneutics in order to avoid the distortions due to the forgetfulness of being. In his later philosophy, Heidegger attempted to reconstruct the "history of being" in order to show how the different epochs in the history of philosophy were dominated by different conceptions of being. His goal is to retrieve the original experience of being present in the early Greek thought that was covered up by later philosophers.

Nicolai Hartmann is a 20th-century philosopher within the continental tradition of philosophy. He interprets ontology as Aristotle's science of being qua being: the science of the most general characteristics of entities, usually referred to as categories, and the relations between them. According to Hartmann, the most general categories are moments of being (existence and essence), modes of being (reality and ideality) and modalities of being (possibility, actuality and necessity). Every entity has both existence and essence. Reality and ideality, by contrast, are two disjunctive categories: every entity is either real or ideal. Ideal entities are universal, returnable and always existing while real entities are individual, unique and destructible. Among the ideal entities are mathematical objects and values. The modalities of being are divided into the absolute modalities (actuality and non-actuality) and the relative modalities (possibility, impossibility and necessity). The relative modalities are relative in the sense that they depend on the absolute modalities: something is possible, impossible or necessary because something else is actual. Hartmann asserts that reality is made up of four levels (inanimate, biological, psychological and spiritual) that form a hierarchy.

Rudolf Carnap proposed that the truth value of ontological statements about the existence of entities depends on the linguistic framework in which these statements are made: they are internal to the framework. As such, they are often trivial in that it just depends on the rules and definitions within this framework. For example, it follows analytically from the rules and definitions within the mathematical framework that numbers exist. The problem Carnap saw with traditional ontologists is that they try to make framework-independent or external statements about what really is the case. Such statements are at best pragmatic considerations about which framework to choose and at worst outright meaningless, according to Carnap. For example, there is no matter of fact as to whether realism or idealism is true, their truth depends on the adopted framework. The job of philosophers is not to discover which things exist by themselves but "conceptual engineering": to create interesting frameworks and to explore the consequences of adopting them. The choice of framework is guided by practical considerations like expedience or fruitfulness since there is no framework-independent notion of truth.

The notion of ontological commitment plays a central role in Willard Van Orman Quine's contributions to ontology. A theory is ontologically committed to an entity if that entity must exist in order for the theory to be true.[173] Quine proposed that the best way to determine this is by translating the theory in question into first-order predicate logic. Of special interest in this translation are the logical constants known as existential quantifiers, whose meaning corresponds to expressions like "there exists..." or "for some...". They are used to bind the variables in the expression following the quantifier. The ontological commitments of the theory then correspond to the variables bound by existential quantifiers. This approach is summed up by Quine's famous dictum that "[t]o be is to be the value of a variable". This method by itself is not sufficient for ontology since it depends on a theory in order to result in ontological commitments. Quine proposed that we should base our ontology on our best scientific theory. Various followers of Quine's method chose to apply it to different fields, for example to "everyday conceptions expressed in natural language".

Other ontological topics

Ontological formations

The concept of ontological formations refers to formations of social relations understood as dominant ways of living. Temporal, spatial, corporeal, epistemological, and performative relations are taken to be central to understanding a dominant formation. That is, a particular ontological formation is based on how ontological categories of time, space, embodiment, knowing and performing are lived—objectively and subjectively. Different ontological formations include the customary (including the tribal), the traditional, the modern, and the postmodern. The concept was first introduced by Paul James in 2006, together with a series of writers including Damian Grenfell and Manfred Steger.

In the engaged theory approach, ontological formations are seen as layered and intersecting rather than singular formations. They are 'formations of being'. This approach avoids the usual problems of a Great Divide being posited between the modern and the pre-modern. From a philosophical distinction concerning different formations of being, the concept then provides a way of translating into practical understandings concerning how humans might design cities and communities that live creatively across different ontological formations, for example cities that are not completely dominated by modern valences of spatial configuration. Here the work of Tony Fry is important.

Ontology of fictional characters

According to Edward N. Zalta, the ontology of fiction analyses such sentences as:

According to Amie L. Thomasson, fictional discourse can be of four sorts:

  • Uttered within works of fiction;
  • Philosophical exercises such as 'Captain Marvel does not exist';
  • Treating fictional characters as if they were 'real', such as 'Superman can leap tall buildings;' and
  • Discourse about works of fiction, such as 'Professor Higgins was created by George Bernard Shaw'.

Jeremy Bentham distinguished three kinds of entities:

  • the real: those that can be perceived, or can be inferred from perception.
  • the fictitious: abstractions that referred to perceptible things.
  • the fabulous: those that can be found only in the imagination, where the word 'exist' applies to such only in the sense that they do not really exist.

Francis Herbert Bradley thought that real things exist respectively at particular times and places. He recognised several kinds of entity:

  • the genuinely historical;
  • the fictional;
  • the real;
  • the merely imagined;
  • the existent; and
  • the non-existent.

Alexius Meinong would put fictional entities into the category which he called subsistence. This category contains objects that neither exist spatially or non-spatially. However, they do have properties. The properties are given to these objects in the way they are said to be described. For example, we can talk about the tall unicorn even though the tall unicorn does not exist. We can say the unicorn is in fact tall because this follows from the properties in which the object is characterized.

Ontological and epistemological certainty

René Descartes, with cogito, ergo sum (je pense donc je suis, "I think, therefore I am"), argued that a person's thinking agency, his res cogitans, as distinct from his material body, his res extensa, is something that we can know exists with epistemological certainty. Descartes argued further that this knowledge could lead to a proof of the certainty of the existence of God, using the ontological argument that had been formulated first by Anselm of Canterbury.

Body and environment, questioning the meaning of being

Schools of subjectivism, objectivism and relativism existed at various times in the 20th century, and the postmodernists and body philosophers tried to reframe all these questions in terms of bodies taking some specific action in an environment. This relied to a great degree on insights derived from scientific research into animals taking instinctive action in natural and artificial settings—as studied by biology, ecology, and cognitive science.

The processes by which bodies related to environments became of great concern, and the idea of being itself became difficult to really define. What did people mean when they said "A is B", "A must be B", "A was B"...? Some linguists advocated dropping the verb "to be" from the English language, leaving "E Prime", supposedly less prone to bad abstractions. Others, mostly philosophers, tried to dig into the word and its usage. Martin Heidegger distinguished human being as existence from the being of things in the world. Heidegger proposes that our way of being human and the way the world is for us are cast historically through a fundamental ontological questioning. These fundamental ontological categories provide the basis for communication in an age: a horizon of unspoken and seemingly unquestionable background meanings, such as human beings understood unquestioningly as subjects and other entities understood unquestioningly as objects. Because these basic ontological meanings both generate and are regenerated in everyday interactions, the locus of our way of being in a historical epoch is the communicative event of language in use. For Heidegger, however, communication in the first place is not among human beings, but language itself shapes up in response to questioning (the inexhaustible meaning of) being. Even the focus of traditional ontology on the 'whatness' or quidditas of beings in their substantial, standing presence can be shifted to pose the question of the 'whoness' of human being itself.

Ontology and language

Some philosophers suggest that the question of "What is?" is (at least in part) an issue of usage rather than a question about facts. This perspective is conveyed by an analogy made by Donald Davidson: Suppose a person refers to a 'cup' as a 'chair' and makes some comments pertinent to a cup, but uses the word 'chair' consistently throughout instead of 'cup'. One might readily catch on that this person simply calls a 'cup' a 'chair' and the oddity is explained. Analogously, if we find people asserting 'there are' such-and-such, and we do not ourselves think that 'such-and-such' exist, we might conclude that these people are not nuts (Davidson calls this assumption 'charity'), they simply use 'there are' differently than we do. The question of What is? is at least partly a topic in the philosophy of language, and is not entirely about ontology itself. This viewpoint has been expressed by Eli Hirsch.

Hirsch interprets Hilary Putnam as asserting that different concepts of "the existence of something" can be correct. This position does not contradict the view that some things do exist, but points out that different 'languages' will have different rules about assigning this property. How to determine the 'fitness' of a 'language' to the world then becomes a subject for investigation.

Common to all Indo-European copula languages is the double use of the verb "to be" in both stating that entity X exists ("X is.") as well as stating that X has a property ("X is P"). It is sometimes argued that a third use is also distinct, stating that X is a member of a class ("X is a C"). In other language families these roles may have completely different verbs and are less likely to be confused with one another. For example they might say something like "the car has redness" rather than "the car is red." Hence any discussion of "being" in Indo-European language philosophy may need to make distinctions between these senses.

Ontology and human geography

In human geography there are two types of ontology: small "o" which accounts for the practical orientation, describing functions of being a part of the group, thought to oversimplify and ignore key activities. The other "o", or big "O", systematically, logically, and rationally describes the essential characteristics and universal traits. This concept relates closely to Plato's view that the human mind can only perceive a bigger world if they continue to live within the confines of their "caves". However, in spite of the differences, ontology relies on the symbolic agreements among members. That said, ontology is crucial for the axiomatic language frameworks.

Anthropology

The topic of ontology has received increased attention in anthropology since the 1990s. This is sometimes termed the "ontological turn". This type of inquiry is focused on how people from different cultures experience and understand the nature of being. Specific interest in this regard has been given to the ontological outlook of indigenous people and how their outlook tends to differ from a more Western perspective. As an example of this contrast, it has been argued that various indigenous communities ascribe intentionality to non-human entities, like plants, forests, or rivers. This outlook is known as animism.

Reality and actuality

According to Alfred N. Whitehead, for ontology, it is useful to distinguish the terms 'reality' and 'actuality'. In this view, an 'actual entity' has a philosophical status of fundamental ontological priority, while a 'real entity' is one which may be actual, or may derive its reality from its logical relation to some actual entity or entities. For example, an occasion in the life of Socrates is an actual entity. But Socrates' being a man does not make 'man' an actual entity, because it refers indeterminately to many actual entities, such as several occasions in the life of Socrates, and also to several occasions in the lives of Alcibiades, and of others. But the notion of man is real; it derives its reality from its reference to those many actual occasions, each of which is an actual entity. An actual occasion is a concrete entity, while terms such as 'man' are abstractions from many concrete relevant entities.

According to Whitehead, an actual entity must earn its philosophical status of fundamental ontological priority by satisfying several philosophical criteria, as follows:

  • There is no going behind an actual entity, to find something more fundamental in fact or in efficacy. This criterion is to be regarded as expressing an axiom, or postulated distinguished doctrine.
  • An actual entity must be completely determinate in the sense that there may be no confusion about its identity that would allow it to be confounded with another actual entity. In this sense an actual entity is completely concrete, with no potential to be something other than itself. It is what it is. It is a source of potentiality for the creation of other actual entities, of which it may be said to be a part cause. Likewise it is the concretion or realization of potentialities of other actual entities which are its partial causes.
  • Causation between actual entities is essential to their actuality. Consequently, for Whitehead, each actual entity has its distinct and definite extension in physical Minkowski space, and so is uniquely identifiable. A description in Minkowski space supports descriptions in time and space for particular observers.
  • It is part of the aim of the philosophy of such an ontology as Whitehead's that the actual entities should be all alike, qua actual entities; they should all satisfy a single definite set of well stated ontological criteria of actuality.

Whitehead proposed that his notion of an occasion of experience satisfies the criteria for its status as the philosophically preferred definition of an actual entity. From a purely logical point of view, each occasion of experience has in full measure the characters of both objective and subjective reality. Subjectivity and objectivity refer to different aspects of an occasion of experience, and in no way do they exclude each other.

Examples of other philosophical proposals or candidates as actual entities, in this view, are Aristotle's 'substances', Leibniz' monads, and Descartes' res verae, and the more modern 'states of affairs'. Aristotle's substances, such as Socrates, have behind them as more fundamental the 'primary substances', and in this sense do not satisfy Whitehead's criteria. Whitehead is not happy with Leibniz' monads as actual entities because they are "windowless" and do not cause each other. 'States of affairs' are often not closely defined, often without specific mention of extension in physical Minkowski space; they are therefore not necessarily processes of becoming, but may be as their name suggests, simply static states in some sense. States of affairs are contingent on particulars, and therefore have something behind them. One summary of the Whiteheadian actual entity is that it is a process of becoming. Another summary, referring to its causal linkage to other actual entities, is that it is "all window", in contrast with Leibniz' windowless monads.

This view allows philosophical entities other than actual entities to really exist, but not as fundamentally and primarily factual or causally efficacious; they have existence as abstractions, with reality only derived from their reference to actual entities. A Whiteheadian actual entity has a unique and completely definite place and time. Whiteheadian abstractions are not so tightly defined in time and place, and in the extreme, some are timeless and placeless, or 'eternal' entities. All abstractions have logical or conceptual rather than efficacious existence; their lack of definite time does not make them unreal if they refer to actual entities. Whitehead calls this 'the ontological principle'.

Microcosmic ontology

There is an established and long philosophical history of the concept of atoms as microscopic physical objects. They are far too small to be visible to the naked eye. It was as recent as the nineteenth century that precise estimates of the sizes of putative physical atoms began to become plausible. Almost direct empirical observation of atomic effects was due to the theoretical investigation of Brownian motion by Albert Einstein in the very early twentieth century. But even then, the real existence of atoms was debated by some. Such debate might be labeled 'microcosmic ontology'. Here the word 'microcosm' is used to indicate a physical world of small entities, such as for example atoms.

Subatomic particles are usually considered to be much smaller than atoms. Their real or actual existence may be very difficult to demonstrate empirically. A distinction is sometimes drawn between actual and virtual subatomic particles. Reasonably, one may ask, in what sense, if any, do virtual particles exist as physical entities? For atomic and subatomic particles, difficult questions arise, such as do they possess a precise position, or a precise momentum? A question that continues to be controversial is "to what kind of physical thing, if any, does the quantum mechanical wave function refer?"

Ontological argument

In the Western Christian tradition, in his 1078 work Proslogion, Anselm of Canterbury proposed what is known as 'the ontological argument' for the existence of God. Anselm defined God as "that than which nothing greater can be thought", and argued that this being must exist in the mind, even in the mind of the person who denies the existence of God. He suggested that, if the greatest possible being exists in the mind, it must also exist in reality. If it only exists in the mind, then an even greater being must be possible—one which exists both in the mind and in reality. Therefore, this greatest possible being must exist in reality. Seventeenth century French philosopher René Descartes deployed a similar argument. Descartes published several variations of his argument, each of which centred on the idea that God's existence is immediately inferable from a "clear and distinct" idea of a supremely perfect being. In the early eighteenth century, Gottfried Leibniz augmented Descartes's ideas in an attempt to prove that a "supremely perfect" being is a coherent concept. Norman Malcolm revived the ontological argument in 1960 when he located a second, stronger ontological argument in Anselm's work; Alvin Plantinga challenged this argument and proposed an alternative, based on modal logic. Attempts have also been made to validate Anselm's proof using an automated theorem prover.

More recently, Kurt Gödel proposed a formal argument for God's existence. Other arguments for God's existence have been advanced, including those made by Islamic philosophers Mulla Sadra[207] and Allama Tabatabai.

Hintikka's locution for existence

Jaakko Hintikka puts the view that a useful explication of the notion of existence is in the words "one can find," implicitly in some world or universe of discourse.

Operator (computer programming)

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