This is a list of some of the major unsolved problems in philosophy. Clearly, unsolved philosophical problems exist in the lay sense (e.g. "What is the meaning of life?", "Where did we come from?", "What is reality?",
etc.). However, professional philosophers generally accord serious
philosophical problems specific names or questions, which indicate a
particular method of attack or line of reasoning. As a result, broad and
untenable topics become manageable. It would therefore be beyond the
scope of this article to categorize "life" (and similar vague
categories) as an unsolved philosophical problem.
Aesthetics
Essentialism
In art, essentialism is the idea that each medium has its own particular strengths and weaknesses, contingent on its mode of communication. A chase scene, for example, may be appropriate for motion pictures, but poorly realized in poetry,
because the essential components of the poetic medium are ill suited to
convey the information of a chase scene. This idea may be further
refined, and it may be said that the haiku is a poor vehicle for describing a lover's affection, as opposed to the sonnet.
Essentialism is attractive to artists, because it not only delineates
the role of art and media, but also prescribes a method for evaluating
art (quality correlates to the degree of organic form).
However, considerable criticism has been leveled at essentialism, which
has been unable to formally define organic form or for that matter,
medium. What, after all, is the medium of poetry? If it is language, how
is this distinct from the medium of prose fiction? Is the distinction
really a distinction in medium or genre?
Questions about organic form, its definition, and its role in art
remain controversial. Generally, working artists accept some form of the
concept of organic form, whereas philosophers have tended to regard it
as vague and irrelevant.
Art objects
This problem originally arose from the practice rather than theory of art. Marcel Duchamp,
in the 20th century, challenged conventional notions of what "art" is,
placing ordinary objects in galleries to prove that the context rather
than content of an art piece determines what art is. In music, John Cage
followed up on Duchamp's ideas, asserting that the term "music" applied
simply to the sounds heard within a fixed interval of time.
While it is easy to dismiss these assertions, further investigation shows that Duchamp and Cage are not so easily disproved. For example, if a pianist plays a Chopinetude,
but his finger slips missing one note, is it still the Chopin etude or a
new piece of music entirely? Most people would agree that it is still a
Chopin etude (albeit with a missing note), which brings into play the Sorites paradox,
mentioned below. If one accepts that this is not a fundamentally
changed work of music, however, is one implicitly agreeing with Cage
that it is merely the duration and context of musical performance,
rather than the precise content, which determines what music is? Hence,
the question is what the criteria for art objects are and whether these
criteria are entirely context-dependent.
Philosophy of language
Counterfactuals
A counterfactual statement is a conditional statement with a false antecedent. For example, the statement "If Joseph Swan had not invented the modern incandescent light bulb,
then someone else would have invented it anyway" is a counterfactual,
because in fact, Joseph Swan invented the modern incandescent light
bulb. The most immediate task concerning counterfactuals is that of
explaining their truth-conditions. As a start, one might assert that
background information is assumed when stating and interpreting
counterfactual conditionals and that this background information is just
every true statement about the world as it is (pre-counterfactual). In
the case of the Swan statement, we have certain trends in the history of
technology, the utility of artificial light, the discovery of
electricity, and so on. We quickly encounter an error with this initial
account: among the true statements will be "Joseph Swan did invent the
modern incandescent light bulb." From the conjunction of this statement
(call it "S") and the antecedent of the counterfactual ("¬S"), we can
derive any conclusion, and we have the unwelcome result that any
statement follows from any counterfactual (see the principle of explosion). Nelson Goodman takes up this and related issues in his seminal Fact, Fiction, and Forecast; and David Lewis's influential articulation of possible world theory is popularly applied in efforts to solve it.
Epistemology
Epistemological problems are concerned with the nature, scope and limitations of knowledge.
Epistemology may also be described as the study of knowledge.
Gettier problem
Plato suggests, in his Theaetetus (210a) and Meno
(97a–98b), that "knowledge" may be defined as justified true belief.
For over two millennia, this definition of knowledge has been reinforced
and accepted by subsequent philosophers. An item of information's
justifiability, truth, and belief have been seen as the necessary and
sufficient conditions for knowledge.
In 1963, Edmund Gettier published an article in the journal "Analysis",
a peer reviewed academic journal of philosophy, entitled "Is Justified
True Belief Knowledge?" which offered instances of justified true belief
that do not conform to the generally understood meaning of "knowledge."
Gettier's examples hinged on instances of epistemic
luck: cases where a person appears to have sound evidence for a
proposition, and that proposition is in fact true, but the apparent
evidence is not causally related to the proposition's truth.
In response to Gettier's article, numerous philosophers
have offered modified criteria for "knowledge." There is no general
consensus to adopt any of the modified definitions yet proposed.
Finally, if infallibilism
is true, that would seem to definitively solve the Gettier problem for
good--the idea is that knowledge requires certainty, such that,
certainty is what serves to bridge the gap so that we arrive at
knowledge, which means we would have an adequate definition of
knowledge. However, infallibilism is rejected by the overwhelming
majority of philosophers/epistemologists, even though it would solve the
Gettier problem (if true).
Problem of the criterion
Overlooking for a moment the complications posed by Gettier problems,
philosophy has essentially continued to operate on the principle that
knowledge is justified true belief. The obvious question that this
definition entails is how one can know whether one's justification is
sound. One must therefore provide a justification for the justification.
That justification itself requires justification, and the questioning
continues interminably.
The conclusion is that no one can truly have knowledge of
anything, since it is, due to this infinite regression, impossible to
satisfy the justification element. In practice, this has caused little
concern to philosophers, since the demarcation between a reasonably
exhaustive investigation and superfluous investigation is usually clear.
Others argue for forms of coherentist systems, e.g. Susan Haack. Recent work by Peter D. Klein views knowledge as essentially defeasible. Therefore, an infinite regress is unproblematic, since any known fact may be overthrown on sufficiently in-depth investigation.
Molyneux problem
The Molyneux problem dates back to the following question posed by William Molyneux to John Locke in the 17th century: if a man born blind, and able to distinguish by touch between a cube and a globe,
were made to see, could he now tell by sight which was the cube and
which the globe, before he touched them? The problem raises fundamental
issues in epistemology and the philosophy of mind, and was widely discussed after Locke included it in the second edition of his Essay Concerning Human Understanding.
A similar problem was also addressed earlier in the 12th century by Ibn Tufail (Abubacer), in his philosophical novel, Hayy ibn Yaqdhan (Philosophus Autodidactus). His version of the problem, however, dealt mainly with colors rather than shapes.
Modern science may now have the tools necessary to test this
problem in controlled environments. The resolution of this problem is in
some sense provided by the study of human subjects who gain vision
after extended congenital blindness. In one such study, subjects were
unable to immediately link objects known by touch to their visual
appearance, and only gradually developed the ability to do so over a
period of days or months. This indicates that this may no longer be an unsolved problem in philosophy.
Münchhausen trilemma
The Münchhausen trilemma, also called Agrippa's trilemma, purports that it is impossible to prove any certain truth even in fields such as logic and mathematics. According to this argument, the proof of any theory rests either on circular reasoning, infinite regress, or unproven axioms.
Qualia
The question hinges on whether color
is a product of the mind or an inherent property of objects. While most
philosophers will agree that color assignment corresponds to spectra of
light frequencies,
it is not at all clear whether the particular psychological phenomena
of color are imposed on these visual signals by the mind, or whether
such qualia are somehow naturally associated with their noumena.
Another way to look at this question is to assume two people ("Fred"
and "George" for the sake of convenience) see colors differently. That
is, when Fred sees the sky, his mind interprets this light signal as
blue. He calls the sky "blue." However, when George sees the sky, his
mind assigns green to that light frequency. If Fred were able to step
into George's mind, he would be amazed that George saw green skies.
However, George has learned to associate the word "blue" with what his
mind sees as green, and so he calls the sky "blue", because for him the
color green has the name "blue." The question is whether blue must be
blue for all people, or whether the perception of that particular color is assigned by the mind.
This extends to all areas of the physical reality, where the
outside world we perceive is merely a representation of what is
impressed upon the senses. The objects we see are in truth wave-emitting
(or reflecting) objects which the brain shows to the conscious self in
various forms and colors. Whether the colors and forms experienced
perfectly match between person to person, may never be known. That
people can communicate accurately shows that the order and
proportionality in which experience is interpreted is generally
reliable. Thus one's reality is, at least, compatible to another
person's in terms of structure and ratio.
Ethics
Moral luck
The problem of moral luck is that some people are born into, live
within, and experience circumstances that seem to change their moral
culpability when all other factors remain the same.
For instance, a case of circumstantial moral luck: a poor
person is born into a poor family, and has no other way to feed himself
so he steals his food. Another person, born into a very wealthy family,
does very little but has ample food and does not need to steal to get
it. Should the poor person be more morally blameworthy than the rich
person? After all, it is not his fault that he was born into such
circumstances, but a matter of "luck".
A related case is resultant moral luck. For instance, two
persons behave in a morally culpable way, such as driving carelessly,
but end up producing unequal amounts of harm: one strikes a pedestrian
and kills him, while the other does not. That one driver caused a death
and the other did not is no part of the drivers' intentional actions;
yet most observers would likely ascribe greater blame to the driver who
killed (compare consequentialism and
choice).
The fundamental question of moral luck is how our moral responsibility is changed by factors over which we have no control.
Moral knowledge
Are
moral facts possible, what do they consist in, and how do we come to
know them? Rightness and wrongness seem strange kinds of entities, and
different from the usual properties of things in the world, such as
wetness, being red, or solidity. Richmond Campbell has outlined these kinds of issues in his encyclopedia article Moral Epistemology.
In particular, he considers three alternative explanations of
moral facts as: theological, (supernatural, the commands of God);
non-natural (based on intuitions); or simply natural properties (such as
leading to pleasure or to happiness). There are cogent arguments
against each of these alternative accounts, he claims, and there has not
been any fourth alternative proposed. So the existence of moral
knowledge and moral facts remains dubious and in need of further
investigation. But moral knowledge supposedly already plays an important
part in our everyday thinking, in our legal systems and criminal
investigations.
Philosophy of mathematics
Mathematical objects
What are numbers, sets, groups, points,
etc.? Are they real objects or are they simply relationships that
necessarily exist in all structures? Although many disparate views exist
regarding what a mathematical object is, the discussion may be roughly
partitioned into two opposing schools of thought: platonism, which asserts that mathematical objects are real, and formalism, which asserts that mathematical objects are merely formal constructions. This dispute may be better understood when considering specific examples, such as the "continuum hypothesis". The continuum hypothesis has been proven independent of the ZF axioms of set theory,
so within that system, the proposition can neither be proven true nor
proven false. A formalist would therefore say that the continuum
hypothesis is neither true nor false, unless you further refine the
context of the question. A platonist, however, would assert that there
either does or does not exist a transfinite set with a cardinality less than the continuum but greater than any countable set. So, regardless of whether it has been proven unprovable, the platonist would argue that an answer nonetheless does exist.
Otherwise known as the "paradox
of the heap", the question regards how one defines a "thing." Is a bale
of hay still a bale of hay if you remove one straw? If so, is it still a
bale of hay if you remove another straw? If you continue this way, you
will eventually deplete the entire bale of hay, and the question is: at
what point is it no longer a bale of hay? While this may initially seem
like a superficial problem, it penetrates to fundamental issues
regarding how we define objects. This is similar to Theseus' paradox and the Continuum fallacy.
Theseus' Paradox
Also
known as the Ship of Theseus, this is a classical paradox on the first
branch of metaphysics, Ontology (philosophy of existence &
identity). The paradox runs thus: There used to be the
great ship of Theseus which was made out of, say, 100 parts. Each part
has a single corresponding replacement part in the ship's storeroom. The
ship then sets out on a voyage. The ship sails through monster-infested
waters, and every day, a single piece is damaged and has to be
replaced. On the hundredth day, the ship sails back to port, the voyage
completed. Through the course of this journey, everything on the ship
has been replaced. So, is the ship sailing back home the ship of Theseus
or no?
If yes, consider this: the broken original parts are repaired and
re-assembled. Is this the ship of Theseus or no?
If no, let us name the ship that sails into port "The
Argo". At what point (during the journey) did the crew of the Theseus
become the crew of the Argo? And what ship is sailing on the fiftieth
day? If both the ships trade a single piece, are they still the same
ships?
This paradox is a minor variation of the Sorites Paradox above,
and has many variations itself. Both sides of the paradox have
convincing arguments and counter-arguments, though no one is close to
proving it completely.
Material implication
People have a pretty clear idea what if-then means. In formal logic
however, material implication defines if-then, which is not consistent
with the common understanding of conditionals. In formal logic, the
statement "If today is Saturday, then 1+1=2" is true. However, '1+1=2'
is true regardless of the content of the antecedent; a causal or
meaningful relation is not required. The statement as a whole must be
true, because 1+1=2 cannot be false. (If it could, then on a given
Saturday, so could the statement). Formal logic has shown itself
extremely useful in formalizing argumentation, philosophical reasoning,
and mathematics. The discrepancy between material implication and the
general conception of conditionals however is a topic of intense
investigation: whether it is an inadequacy in formal logic, an ambiguity
of ordinary language, or as championed by H.P. Grice, that no discrepancy exists.
Philosophy of mind
Mind–body problem
The mind–body problem
is the problem of determining the relationship between the human body
and the human mind. Philosophical positions on this question are
generally predicated on either a reduction of one to the other, or a
belief in the discrete coexistence of both. This problem is usually
exemplified by Descartes, who championed a dualistic picture. The
problem therein is to establish how the mind and body communicate in a dualistic framework. Neurobiology and emergence
have further complicated the problem by allowing the material functions
of the mind to be a representation of some further aspect emerging from
the mechanistic properties of the brain. The brain essentially stops
generating conscious thought during deep sleep; the ability to restore
such a pattern remains a mystery to science and is a subject of current
research (see also neurophilosophy).
Cognition and AI
This problem actually defines a field, however its pursuits are specific and easily stated. Firstly, what are the criteria for intelligence? What are the necessary components for defining consciousness? Secondly, how can an outside observer test for these criteria? The "Turing Test"
is often cited as a prototypical test of intelligence, although it is
almost universally regarded as insufficient. It involves a conversation
between a sentient being and a machine, and if the being can't tell he
is talking to a machine, it is considered intelligent. A well trained
machine, however, could theoretically "parrot" its way through the test.
This raises the corollary question of whether it is possible to artificially create consciousness (usually in the context of computers or machines), and of how to tell a well-trained mimic from a sentient entity.
A related field is the ethics of artificial intelligence, which addresses such problems as the existence of moral personhood of AIs, the possibility of moral obligations to
AIs (for instance, the right of a possibly sentient computer system to
not be turned off), and the question of making AIs that behave ethically
towards humans and others.
Hard problem of consciousness
The hard problem of consciousness is the question of what consciousness is and why we have consciousness as opposed to being philosophical zombies.
The adjective "hard" is to contrast with the "easy" consciousness
problems, which seek to explain the mechanisms of consciousness ("why"
versus "how", or final cause versus efficient cause).
The hard problem of consciousness is questioning whether all beings
undergo an experience of consciousness rather than questioning the
neurological makeup of beings.
Philosophy of science
Problem of induction
Intuitively, it seems to be the case that we know certain things with
absolute, complete, utter, unshakable certainty. For example, if you
travel to the Arctic and touch an iceberg, you know that it would feel
cold. These things that we know from experience are known through
induction. The problem of induction in short; (1) any inductive
statement (like the sun will rise tomorrow) can only be deductively
shown if one assumes that nature is uniform. (2) the only way to show
that nature is uniform is by using induction. Thus induction cannot be
justified deductively.
Demarcation problem
‘The problem of demarcation’ is an expression introduced by Karl Popper
to refer to ‘the problem of finding a criterion which would enable us
to distinguish between the empirical sciences on the one hand, and
mathematics and logic as well as "metaphysical" systems on the other’.
Popper attributes this problem to Kant. Although Popper mentions mathematics and logic, other writers focus on distinguishing science from metaphysics.
Realism
Does a world independent of human beliefs and representations exist?
Is such a world empirically accessible, or would such a world be forever
beyond the bounds of human sense and hence unknowable? Can human
activity and agency change the objective structure of the world? These
questions continue to receive much attention in the philosophy of
science. A clear "yes" to the first question is a hallmark of the
scientific realism perspective. Philosophers such as Bas van Fraassen have important and interesting answers to the second question. In addition to the realism vs. empiricism axis of debate, there is a realism vs. social constructivism axis which heats many academic passions. With respect to the third question, Paul Boghossian's "Fear of Knowledge: Against Relativism and Constructivism". Oxford University Press. 2006. is a powerful critique of social constructivism, for instance. Ian Hacking's The Social Construction of What?
(Harvard UP, 2000) constitutes a more moderate critique of
constructivism, which usefully disambiguates confusing polysemy of the
term "constructivism."
Thomism is the philosophical school that arose as a legacy of the work and thought of Thomas Aquinas (1225–1274), philosopher, theologian, and Doctor of the Church. In philosophy, Aquinas' disputed questions and commentaries on Aristotle are perhaps his most well-known works. In theology, his Summa Theologica is one of the most influential documents in medieval theology and continues to be the central point of reference for the philosophy and theology of the Catholic Church. In the 1914 encyclical Doctoris AngeliciPope Pius X
cautioned that the teachings of the Church cannot be understood without
the basic philosophical underpinnings of Aquinas' major theses:
The
capital theses in the philosophy of St. Thomas are not to be placed in
the category of opinions capable of being debated one way or another,
but are to be considered as the foundations upon which the whole science
of natural and divine things is based; if such principles are once
removed or in any way impaired, it must necessarily follow that students
of the sacred sciences will ultimately fail to perceive so much as the
meaning of the words in which the dogmas of divine revelation are
proposed by the magistracy of the Church.
Thomas Aquinas believed that truth is to be accepted no matter where it is found. His doctrines draw from Greek, Roman, Jewish, philosophers. Specifically, he was a realist (i.e., he, unlike the skeptics, believed that the world can be known as it is). He largely followed Aristotelian terminology and metaphysics, and wrote comprehensive commentaries on Aristotle, often affirming Aristotle's views with independent arguments. Aquinas respectfully referred to Aristotle simply as "the Philosopher". He also adhered to some neoplatonic
principles, for example that "it is absolutely true that there is first
something which is essentially being and essentially good, which we
call God, ... [and that] everything can be called good and a being,
inasmuch as it participates in it by way of a certain assimilation..."
24 Thomistic Theses
With the decree Postquam sanctissimus of 27 July 1914, Pope Pius X
declared that 24 theses formulated by "teachers from various
institutions ... clearly contain the principles and more important
thoughts" of Aquinas. Principal contributors to the Church's official
statement of the "24 Theses" of Thomism include Dominican philosopher and theologian Edouard Hugon of the Pontifical University of Saint Thomas Aquinas, Angelicum and Jesuit philosopher theologian Guido Mattiussi of the Pontifical Gregorian University.
Ontology
Potency and Act divide being in such a way that whatever is, is either pure act, or of necessity it is composed of potency and act as primary and intrinsic principles.
Since act is perfection, it is not limited except through a potency
which itself is a capacity for perfection. Hence in any order in which
an act is pure act, it will only exist, in that order, as a unique and
unlimited act. But whenever it is finite and manifold, it has entered
into a true composition with potency.
Consequently, the one God, unique and simple, alone subsists in
absolute being. All other things that participate in being have a nature
whereby their being is restricted; they are constituted of essence and
being, as really distinct principles.
A thing is called a being because of "esse". God and creature are
not called beings univocally, nor wholly equivocally, but analogically,
by an analogy both of attribution and of proportionality.
In every creature there is also a real composition of the subsisting subject and of added secondary forms, i.e. accidental forms. Such composition cannot be understood unless being is really received in an essence distinct from it.
Besides the absolute accidents there is also the relative accident,
relation. Although by reason of its own character relation does not
signify anything inhering in another, it nevertheless often has a cause
in things, and hence a real entity distinct from the subject.
A spiritual creature
is wholly simple in its essence. Yet there is still a twofold
composition in the spiritual creature, namely, that of the essence with
being, and that of the substance with accidents.
However, the corporeal creature is composed of act and potency even
in its very essence. These act and potency in the order of essence are
designated by the names form and matter respectively.
Cosmology
Neither the matter nor the form have being of themselves, nor are
they produced or corrupted of themselves, nor are they included in any
category otherwise than reductively, as substantial principles.
Although extension in quantitative parts follows upon a corporeal
nature, nevertheless it is not the same for a body to be a substance and
for it to be quantified. For of itself substance is indivisible, not
indeed as a point is indivisible, but as that which falls outside the
order of dimensions is indivisible. But quantity, which gives the
substance extension, really differs from the substance and is truly an
accident.
The principle of individuation, i.e., of numerical distinction of
one individual from another with the same specific nature, is matter
designated by quantity. Thus in pure spirits there cannot be more than
one individual in the same specific nature.
By virtue of a body's quantity itself, the body is circumscriptively
in a place, and in one place alone circumscriptively, no matter what
power might be brought to bear.
Bodies are divided into two groups; for some are living and others
are devoid of life. In the case of the living things, in order that
there be in the same subject an essentially moving part and an
essentially moved part, the substantial form, which is designated by the
name soul, requires an organic disposition, i.e. heterogeneous parts.
Psychology
Souls in the vegetative and sensitive orders cannot subsist of
themselves, nor are they produced of themselves. Rather, they are no
more than principles whereby the living thing exists and lives; and
since they are wholly dependent upon matter, they are incidentally
corrupted through the corruption of the composite.
On the other hand, the human soul subsists of itself. When it can be
infused into a sufficiently disposed subject, it is created by God. By
its very nature, it is incorruptible and immortal.
This rational soul is united to the body in such a manner that it is
the only substantial form of the body. By virtue of his soul a man is a
man, an animal, a living thing, a body, a substance and a being.
Therefore, the soul gives man every essential degree of perfection;
moreover, it gives the body a share in the act of being whereby it
itself exists.
From the human soul there naturally issue forth powers pertaining to
two orders, the organic and the non-organic. The organic powers, among
which are the senses, have the composite as their subject. The
non-organic powers have the soul alone as their subject. Hence, the
intellect is a power intrinsically independent of any bodily organ.
Intellectuality necessarily follows upon immateriality, and
furthermore, in such manner that the further the distance from matter,
the higher the degree of intellectuality. Any being is the adequate
object of understanding in general. But in the present state of union of
soul and body, quantities abstracted from the material conditions of
individuality are the proper object of the human intellect.
Therefore, we receive knowledge from sensible things. But since
sensible things are not actually intelligible, in addition to the
intellect, which formally understands, an active power must be
acknowledged in the soul, which power abstracts intelligible likeness or
species from sense images in the imagination.
Through these intelligible likenesses or species we directly know
universals, i.e. the natures of things. We attain to singulars by our
senses, and also by our intellect, when it beholds the sense images. But
we ascend to knowledge of spiritual things by analogy.
The will does not precede the intellect but follows upon it. The
will necessarily desires that which is presented to it as a good in
every respect satisfying the appetite. But it freely chooses among the
many goods that are presented to it as desirable according to a
changeable judgment or evaluation. Consequently, the choice follows the
final practical judgment. But the will is the cause of it being the
final one.
God
We do not perceive by an immediate intuition that God exists, nor do we prove it a priori. But we do prove it a posteriori,
i.e., from the things that have been created, following an argument
from the effects to the cause: namely, from things which are moved and
cannot be the adequate source of their motion, to a first unmoved mover;
from the production of the things in this world by causes subordinated
to one another, to a first uncaused cause; from corruptible things which
equally might be or not be, to an absolutely necessary being; from
things which more or less are, live, and understand, according to
degrees of being, living and understanding, to that which is maximally
understanding, maximally living and maximally a being; finally, from the
order of all things, to a separated intellect which has ordered and organized things, and directs them to their end.
The metaphysical motion of the Divine Essence is correctly expressed
by saying that it is identified with the exercised actuality of its own
being, or that it is subsistent being itself. And this is the reason
for its infinite and unlimited perfection.
By reason of the very purity of His being, God is distinguished from
all finite beings. Hence it follows, in the first place, that the world
could only have come from God by creation; secondly, that not even by
way of a miracle can any finite nature be given creative power, which of
itself directly attains the very being of any being; and finally, that
no created agent can in any way influence the being of any effect unless
it has itself been moved by the first Cause.
Univocality is the use of a descriptor in the same sense
when applied to two objects or groups of objects. For instance, when the
word "milk" is applied both to milk produced by cows and by any other
female mammal.
Analogy occurs when a descriptor changes some but not all of
its meaning. For example, the word "healthy" is analogical in that it
applies both to a healthy person or animal (those that enjoy of good
health) and to some food or drink (if it is good for the health).
Equivocation is the complete change in meaning of the descriptor and is an informal fallacy. For example, when the word "bank" is applied to river banks and financial banks, modern philosophers talk of ambiguity.
Further, the usage of "definition" that Aquinas gives is the genus of the being, plus a difference that sets it apart from the genus itself. For instance, the Aristotelian definition of "man" is "rational animal"; its genus being animal, and what sets apart man from other animals is his rationality.
Being
[E]xistence is twofold: one is essential existence or the substantial existence of a thing, for example man exists, and this is existence simpliciter. The other is accidental existence, for example man is white, and this is existence secundum quid.
In Thomist philosophy, the definition of a being is "that which is," which is composed of two parts: "which" refers to its quiddity (literally "whatness"), and "is" refers to its esse (the Latininfinitiveverb "to be"). "Quiddity" is synonymous with essence, form and nature; whereas "esse" refers to the principle of the being's existence. In other words, a being is "an essence that exists."
Being is divided in two ways: that which is in itself (substances), and that which is in another (accidents). Substances are things which exist per se
or in their own right. Accidents are qualities that apply to other
things, such as shape or color: "[A]ccidents must include in their
definition a subject which is outside their genus." Because they only exist in other things, Aquinas holds that metaphysics is primarily the study of substances, as they are the primary mode of being.
The Catholic Encyclopedia pinpoints Aquinas' definition of quiddity as "that which is expressed by its definition." The quiddity or form of a thing is what makes the object what it is: "[T]hrough the form, which is the actuality of matter, matter becomes something actual and something individual," and also, "the form causes matter to be." Thus, it consists of two parts: "prime matter" (matter without form), and substantial form,
which is what causes a substance to have its characteristics. For
instance, an animal can be said to be a being whose matter is its body,
and whose soul is its substantial form. Together, these consist of its quiddity/essence.
Aristotle categorized causality into four subsets in the Metaphysics, which is an integral part of Thomism:
"In one sense the term cause means
(a) that from which, as something intrinsic, a thing comes to be, as the
bronze of a statue and the silver of a goblet, and the genera of these.
In another sense it means (b) the form and pattern of a thing, i.e.,
the intelligible expression of the quiddity and its genera (for
example, the ratio of 2: 1 and number in general are the cause of an
octave chord) and the parts which are included in the intelligible
expression. Again, (c) that from which the first beginning of change or
of rest comes is a cause; for example, an adviser is a cause, and a
father is the cause of a child, and in general a maker is a cause of the
thing made, and a changer a cause of the thing changed. Further, a
thing is a cause (d) inasmuch as it is an end, i.e., that for the sake
of which something is done; for example, health is the cause of walking.
For if we are asked why someone took a walk, we answer, "in order to be
healthy"; and in saying this we think we have given the cause. And
whatever occurs on the way to the end under the motion of something else
is also a cause. For example, reducing, purging, drugs and instruments
are causes of health; for all of these exist for the sake of the end,
although they differ from each other inasmuch as some are instruments
and others are processes."
(a) refers to the material cause, what a being's matter consists of (if applicable).
(b) refers to the formal cause, what a being's essence is.
(c) refers to the efficient cause, what brings about the beginning of, or change to, a being.
(d) refers to the final cause, what a being's purpose is.
Unlike many ancient Greeks, who thought that an infinite regress
of causality is possible (and thus held that the universe is uncaused),
Aquinas argues that an infinite chain never accomplishes its objective
and is thus impossible. Hence, a first cause
is necessary for the existence of anything to be possible. Further, the
First Cause must continuously be in action (similar to how there must
always be a first chain in a chain link), otherwise the series collapses:
The Philosopher says (Metaph. ii, 2)
that "to suppose a thing to be indefinite is to deny that it is good."
But the good is that which has the nature of an end. Therefore it is
contrary to the nature of an end to proceed indefinitely. Therefore it
is necessary to fix one last end.
Thus, both Aristotle and Aquinas conclude that there must be an uncaused Primary Mover, because an infinite regress is impossible.
However, the First Cause does not necessarily have to be
temporally the first. Thus, the question of whether or not the universe
can be imagined as eternal was fiercely debated in the Middle Ages. The University of Paris's condemnation of 1270 denounced the belief that the world is eternal. Aquinas' intellectual rival, Bonaventure, held that the temporality of the universe is demonstrable by reason.
Aquinas' position was that the temporality of the world is an article
of faith, and not demonstrable by reason; though one could reasonably
conclude either that the universe is temporal or eternal.
Goodness
As per the Nicomachean Ethics of Aristotle, Aquinas defines "the good"
as what all things strive for. E.g., a cutting knife is said to be good
if it is effective at its function, cutting. As all things have a
function/final cause, all real things are good. Consequently, evil is nothing but privatio boni, or "lack of good", as Augustine of Hippo defined it.
Dionysius
says (Div. Nom. iv), 'Evil is neither a being nor a good.' I answer
that, one opposite is known through the other, as darkness is known
through light. Hence also what evil is must be known from the nature of
good. Now, we have said above that good is everything appetible; and
thus, since every nature desires its own being and its own perfection,
it must be said also that the being and the perfection of any nature is
good. Hence it cannot be that evil signifies being, or any form or
nature. Therefore it must be that by the name of evil is signified the
absence of good. And this is what is meant by saying that 'evil is
neither a being nor a good.' For since being, as such, is good, the
absence of one implies the absence of the other.
Commentating on the aforementioned, Aquinas says that "there is no
problem from the fact that some men desire evil. For they desire evil
only under the aspect of good, that is, insofar as they think it good.
Hence their intention primarily aims at the good and only incidentally
touches on the evil."
As God is the ultimate end of all things, God is by essence goodness itself. Furthermore, since love is "to wish the good of another," true love in Thomism is to lead another to God. Hence why John the Evangelist says, "Whoever is without love does not know God, for God is love."
Existence of God
Thomas Aquinas holds that the existence of God can be demonstrated by reason, a view that is taught by the Catholic Church. The quinque viae (Latin: five ways) found in the Summa Theologica (I, Q.2, art.3) are five possible ways of demonstrating the existence of God, which today are categorized as:
1. Argumentum ex motu, or the argument of the unmoved mover;
2. Argumentum ex ratione causae efficientis, or the argument of the first cause;
Despite this, Aquinas also thought that sacred mysteries such as the Trinity could only be obtained through revelation; though these truths cannot contradict reason:
The existence of God and other like
truths about God, which can be known by natural reason, are not
articles of faith, but are preambles to the articles; for faith
presupposes natural knowledge, even as grace presupposes nature, and
perfection supposes something that can be perfected. Nevertheless, there
is nothing to prevent a man, who cannot grasp a proof, accepting, as a
matter of faith, something which in itself is capable of being
scientifically known and demonstrated.
Aquinas responds to the problem of evil by saying that God allows evil to exist that good may come of it,
(for goodness done out of free will is superior than goodness done from
biological imperative) but does not personally cause evil Himself.
View of God
Aquinas articulated and defended, both as a philosopher and a theologian, the orthodox Christian view of God. God is the sole being whose existence is the same as His essence: "what subsists in God is His existence." (Hence why God names himself "I Am that I Am" in Exodus 3:14.) Consequently, God cannot be a body (that is, He cannot be composed of matter), He cannot have any accidents, and He must be simple (that is, not separated into parts; the Trinity is one substance in three persons). Further, He is goodness itself, perfect, infinite, omnipotent, omniscient, happiness itself, knowledge itself, love itself, omnipresent, immutable, and eternal. Summing up these properties, Aquinas offers the term actus purus (Latin: "pure actuality").
Aquinas held that not only does God have knowledge of everything, but that God has "the most perfect knowledge," and that it is also true to say that God "is" his understanding.
Aquinas also understands God as the transcendent cause of the
universe, the "first cause of all things, exceeding all things caused by
him," the source of all creaturely being and the cause of every other
cause.
Consequently, God's causality is not like the causality of any other
causes (all other causes are "secondary causes"), because he is the
transcendent source of all being, causing and sustaining every other
existing thing at every instant. Consequently, God's causality is never
in competition with the causality of creatures; rather, God even causes
some things through the causality of creatures.
Aquinas was an advocate of the "analogical way", which says that
because God is infinite, people can only speak of God by analogy, for
some of the aspects of the divine nature are hidden (Deus absconditus) and others revealed (Deus revelatus) to finite human minds. Thomist philosophy holds that we can know about God through his creation (general revelation), but only in an analogous manner.
For instance, we can speak of God's goodness only by understanding that
goodness as applied to humans is similar to, but not identical with,
the goodness of God. Further, he argues that sacred scripture employs figurative language:
"Now it is natural to man to attain to intellectual truths through
sensible objects, because all our knowledge originates from sense. Hence
in Holy Writ, spiritual truths are fittingly taught under the likeness of material things."
In order to demonstrate God's creative power, Aquinas says: "If a
being participates, to a certain degree, in an 'accident,' this
accidental property must have been communicated to it by a cause which
possesses it essentially. Thus iron becomes incandescent by the action
of fire. Now, God is His own power which subsists by itself. The being
which subsists by itself is necessarily one."
Anthropology
Summa Theologiæ, Pars secunda, prima pars. (copy by Peter Schöffer, 1471)
In addition to agreeing with the Aristotelian definition of man as "the rational animal," Aquinas also held various other beliefs about the substance of man. For instance, as the essence (nature) of all men are the same, and the definition of being is "an essence that exists," humans that are real therefore only differ by their specific qualities. More generally speaking, all beings of the same genus have the same essence, and so long as they exist, only differ by accidents and substantial form.
Soul
Thomists define the soul as the substantial form of living beings. Thus, plants have "vegetative souls," animals have "sensitive souls," while human beings alone have "intellectual" – rational and immortal – souls.
For Aristotle, the soul is one, but endowed with five groups of faculties (dunámeis): (1) the "vegetative" faculty (threptikón), concerned with the maintenance and development of organic life; (2) the appetite (oretikón), or the tendency to any good; (3) the faculty of sense perception (aisthetikón); (4) the "locomotive" faculty (kinetikón), which presides over the various bodily movements; and (5) reason (dianoetikón). The Scholastics generally follow Aristotle's classification. For them body and soul are united in one complete substance. The soul is the forma substantialis,
the vital principle, the source of all activities. Hence their science
of the soul deals with functions which nowadays belong to the provinces
of biology and physiology. [...] The nature of the mind and its
relations to the organism are questions that belong to philosophy or
metaphysics.
The appetite of man has two parts, rational and irrational. The
rational part is called the will, and the irrational part is called
passion.
Ethics
Aquinas affirms Aristotle's definition of happiness as "an operation according to perfect virtue", and that "happiness is called man's supreme good, because it is the attainment or enjoyment of the supreme good." Regarding what the virtues are, Aquinas ascertained the cardinal virtues to be prudence, temperance, justice, and fortitude. The cardinal virtues are natural and revealed in nature, and they are binding on everyone. There are, however, three theological virtues: faith, hope, and charity (which is used interchangeably with love in the sense of agape). These are supernatural and are distinct from other virtues in their object, namely, God.
In accordance with Roman Catholic theology, Aquinas argues that humans can neither wish nor do good without divine grace. However, "doing good" here refers to doing good per se: man can
do, moved by God even then but "only" in the sense in which even his
nature depends on God's moving, things that happen to be good in some
respect, and are not sinful, though if he has not grace, it will be
without merit, and he will not succeed in it all the time. Therefore,
happiness is attained through the perseverance of virtue given by the
Grace of God, which is not fully attained on earth; only at the beatific vision. Notably, man cannot attain true happiness without God.
Regarding emotion (used synonymously with the word "passion" in this context), which, following John Damascene, Aquinas defines as "a movement of the sensitive appetite when we imagine good or evil," Thomism repudiates both the Epicurean view that happiness consists in pleasure (sensual experiences that invoke positive emotion), and the Stoic view that emotions are vices by nature. Aquinas takes a moderate view of emotion, quoting Augustine: "They are evil if our love is evil; good if our love is good." While most emotions are morally neutral, some are inherently virtuous (e.g. pity) and some are inherently vicious (e.g. envy).
Thomist ethics hold that it is necessary to observe both circumstances and intention to determine an action's moral value, and therefore Aquinas cannot be said to be strictly either a deontologicalist or a consequentialist. Rather, he would say that an action is morally good if it fulfills God's antecedent will.
In order for a war to be just,
three things are necessary. First, the authority of the sovereign by
whose command the war is to be waged... Secondly, a just cause is required,
namely that those who are attacked, should be attacked because they
deserve it on account of some fault... Thirdly, it is necessary that the
belligerents should have a rightful intention, so that they intend the
advancement of good, or the avoidance of evil...
Thomism recognizes four different species of law, which he defines as
"an ordinance of reason for the common good, made by him who has care
of the community, and promulgated":
Eternal law, which is "the type of Divine Wisdom, as directing all actions and movements;"
Natural law,
"whereby each one knows, and is conscious of, what is good and what is
evil," which is the rational being's participation in the eternal law;
Human or temporal law, laws made by humans by necessity; and
The development of natural law is one of the most influential parts of Thomist philosophy.
Aquinas says that "[the law of nature] is nothing other than the light
of the intellect planted in us by God, by which we know what should be
done and what should be avoided. God gave this light and this law in
creation... For no one is ignorant that what he would not like to be
done to himself he should not do to others, and similar norms." This reflects Paul the Apostle's argument in Romans 2:15, that the "work of the law [is] written in [the Gentiles'] hearts, their conscience bearing witness to them."
... just as by moving natural
causes [God] does not prevent their acts being natural, so by moving
voluntary causes He does not deprive their actions of being voluntary:
but rather is He the cause of this very thing in them; for He operates
in each thing according to its own nature.
Aquinas argues that God offers man both a prevenient grace to enable
him to perform supernaturally good works, and cooperative grace within
the same. The relation of prevenient grace to voluntariness has been the
subject of further debate; the position known here as "Thomist" was
originated by Domingo Báñez and says that God gives an additional grace (the "efficient grace") to the predestined which makes them accept, while Luis de Molina held that God distributes grace according to a middle knowledge, and man can accept it without a different grace. Molinism
is a school that is part of Thomism in the general sense (it originated
in commentaries to Aquinas), yet it must be born in mind that, here,
Thomism and Molinism oppose each other. (The question has been declared
undecided by the Holy See.)
Epistemology
"Whatever is in our intellect must have previously been in the senses."
Aquinas adhered to the correspondence theory of truth, which says that something is true "when it conforms to the external reality." Therefore, any being that exists can be said to be true insofar that it participates in the world.
Aristotle's De anima (On the Soul) divides the mind into three parts: sensation, imagination and intellection. When one perceives an object, his mind composites a sense-image. When he remembers the object he previously sensed, he is imagining its form
(the image of the imagination is often translated as "phantasm"). When
he extracts information from this phantasm, he is using his intellect. Consequently, all human knowledge concerning universals (such as species and properties) are derived from the phantasm ("the received is in the receiver according to the mode of the receiver"),
which itself is a recollection of an experience. Concerning the
question of "Whether the intellect can actually understand through the
intelligible species of which it is possessed, without turning to the
phantasms?" in the Summa Theologica, Aquinas quotes Aristotle in the sed contra: "the soul understands nothing without a phantasm." Hence the peripatetic axiom. (Another theorem to be drawn from this is that error is a result of drawing false conclusions based on our sensations.)
Aquinas shifted Scholasticism away from neoplatonism and towards Aristotle.
The ensuing school of thought, through its influence on Catholicism and
the ethics of the Catholic school, is one of the most influential
philosophies of all time, also significant due to the number of people
living by its teachings.
Triumph of St Thomas Aquinas, Benozzo Gozzoli,1471. Louvre, Paris
Before Aquinas' death, Stephen Tempier, Bishop of Paris, forbade certain positions associated with Aquinas (especially his denial of both universal hylomorphism and a plurality of substantial forms in a single substance) to be taught in the Faculty of Arts at Paris. Through the influence of traditional Augustinian theologians, some theses of Aquinas were condemned in 1277 by the ecclesiastical authorities of Paris and Oxford (the most important theological schools in the Middle Ages). The Franciscan Order opposed the ideas of the Dominican
Aquinas, while the Dominicans institutionally took up the defense of
his work (1286), and thereafter adopted it as an official philosophy of
the order to be taught in their studia. Early opponents of Aquinas include William de la Mare, Henry of Ghent, Giles of Rome, and Jon Duns Scotus.
Thomism remained a doctrine held principally by Dominican theologians, such as Giovanni Capreolo (1380–1444) or Tommaso de Vio
(1468–1534). Eventually, in the 16th century, Thomism found a
stronghold on the Iberian Peninsula, through for example the Dominicans Francisco de Vitoria (particularly noteworthy for his work in natural law theory), Domingo de Soto (notable for his work on economic theory), John of St. Thomas, and Domingo Báñez; the Carmelites of Salamanca (i.e., the Salmanticenses); and even, in a way, the newly formed Jesuits, particularly Francisco Suárez, and Luis de Molina.
The modern period brought considerable difficulty for Thomism.
By the 19th century, Aquinas's theological doctrine was often presented
in seminaries through his Jesuit manualist interpreters, who adopted
his theology in an eclectic way, while his philosophy was often
neglected altogether in favor of modern philosophers. Many think the manualist approach had more in common with Duns Scotus than it did with Aquinas—thus is more properly labeled Neo-Scholasticism. And in all this, the Dominican Order, was having demographic difficulties. Pope Leo XIII attempted a Thomistic revival, particularly with his 1879 encyclical Aeterni Patris and his establishment of the Leonine Commission, established to produce critical editions of Aquinas' opera omnia. This encyclical served as the impetus for the rise of Neothomism, which brought an emphasis on the ethical parts of Thomism, as well as a large part of its views on life, humans, and theology, are found in the various schools of Neothomism. Neothomism held sway as the dominant philosophy of the Roman Catholic Church until the Second Vatican Council, which seemed to confirm the significance of Ressourcement
theology. Thomism remains a school of philosophy today, and influential
in Catholicism, though "The Church has no philosophy of her own nor
does she canonize any one particular philosophy in preference to
others."
In recent years, the cognitive neuroscientist Walter Freeman proposes that Thomism is the philosophical system explaining cognition that is most compatible with neurodynamics, in a 2008 article in the journal Mind and Matter entitled "Nonlinear Brain Dynamics and Intention According to Aquinas."
Influence on Jewish thought
Aquinas' doctrines, because of their close relationship with those of Jewish philosophy, found great favor among Jews. Judah Romano (born 1286) translated Aquinas' ideas from Latin into Hebrew under the title Ma'amar ha-Mamschalim, together with other small treatises extracted from the "Contra Gentiles" ("Neged ha-Umot").
Eli Habillo (1470) translated, without the Hebrew
title, the "Quæstiones Disputatæ," "Quæstio de Anima," his "De Animæ
Facultatibus," under the title "Ma'amar be-KoḦot ha-Nefesh," (edited by
Jellinek); his "De Universalibus" as "Be-Inyan ha-Kolel"; "Shaalot
Ma'amar beNimẓa we-biMehut."
Abraham Nehemiah ben Joseph (1490) translated Aquinas's "Commentarii in Metaphysicam." According to Moses Almosnino, Isaac Abravanel
desired to translate the "Quæstio de Spiritualibus Creaturis."
Abravanel indeed seems to have been well acquainted with the philosophy
of Aquinas, whom he mentions in his work "Mif'alot Elohim" (vi. 3). The
physician Jacob Zahalon (d. 1693) translated some extracts from the Summa contra Gentiles.
Connection with Jewish thought
Aquinas did not disdain to draw upon Jewish philosophical sources. His main work, the Summa Theologica, shows a profound knowledge not only of the writings of Avicebron (Ibn Gabirol), whose name he mentions, but also of most Jewish philosophical works then existing.
Aquinas pronounces himself energetically against the hypothesis of the eternity of the world, in agreement with both Christian and Jewish theology. But as this theory is attributed to Aristotle,
he seeks to demonstrate that the latter did not express himself
categorically on this subject. "The argument," said he, "which Aristotle
presents to support this thesis is not properly called a demonstration,
but is only a reply to the theories of those ancients who supposed that
this world had a beginning and who gave only impossible proofs. There
are three reasons for believing that Aristotle himself attached only a
relative value to this reasoning..." In this, Aquinas paraphrases Maimonides' Guide for the Perplexed, where those reasons are given.
But, meanwhile, I feel greatly
astonished when I observe [the weakness of my mind, and] its proneness
to error. For although, without at all giving expression to what I
think, I consider all this in my own mind, words yet occasionally impede
my progress, and I am almost led into error by the terms of ordinary
language. We say, for example, that we see the same wax when it is
before us, and not that we judge it to be the same from its retaining
the same color and figure: whence I should forthwith be disposed to
conclude that the wax is known by the act of sight, and not by the
intuition of the mind alone, were it not for the analogous instance of
human beings passing on in the street below, as observed from a window.
In this case I do not fail to say that I see the men themselves, just as
I say that I see the wax; and yet what do I see from the window beyond
hats and cloaks that might cover artificial machines, whose motions
might be determined by springs? But I judge that there are human beings
from these appearances, and thus I comprehend, by the faculty of
judgment alone which is in the mind, what I believed I saw with my eyes.
In describing Thomism as a philosophy of common sense, G. K. Chesterton wrote:
Since the modern world began in the sixteenth century, nobody's
system of philosophy has really corresponded to everybody's sense of
reality; to what, if left to themselves, common men would call common
sense. Each started with a paradox; a peculiar point of view demanding
the sacrifice of what they would call a sane point of view. That is the
one thing common to Hobbes and Hegel, to Kant and Bergson, to Berkeley and William James.
A man had to believe something that no normal man would believe, if it
were suddenly propounded to his simplicity; as that law is above right,
or right is outside reason, or things are only as we think them, or
everything is relative to a reality that is not there. The modern
philosopher claims, like a sort of confidence man, that if we will grant
him this, the rest will be easy; he will straighten out the world, if
he is allowed to give this one twist to the mind...
Against all this the philosophy of St. Thomas stands founded on the
universal common conviction that eggs are eggs. The Hegelian may say
that an egg is really a hen, because it is a part of an endless process
of Becoming; the Berkelian may hold that poached eggs
only exist as a dream exists, since it is quite as easy to call the
dream the cause of the eggs as the eggs the cause of the dream; the
Pragmatist may believe that we get the best out of scrambled eggs by
forgetting that they ever were eggs, and only remembering the scramble.
But no pupil of St. Thomas needs to addle his brains in order adequately
to addle his eggs; to put his head at any peculiar angle in looking at
eggs, or squinting at eggs, or winking the other eye in order to see a
new simplification of eggs. The Thomist stands in the broad daylight of
the brotherhood of men, in their common consciousness that eggs are not
hens or dreams or mere practical assumptions; but things attested by the
Authority of the Senses, which is from God.
— Chesterton, St. Thomas Aquinas, p. 147.
History
J. A. Weisheipl emphasizes that within the Dominican Order the history of Thomism has been continuous since the time of Aquinas:
Thomism was always alive in the
Dominican Order, small as it was after the ravages of the Reformation,
the French Revolution, and the Napoleonic occupation. Repeated
legislation of the General Chapters, beginning after the death of St.
Thomas, as well as the Constitutions of the Order, required all
Dominicans to teach the doctrine of St. Thomas both in philosophy and in
theology.
Outside the Dominican Order
Thomism has had varying fortunes leading some to periodize it
historically or thematically. Weisheipl distinguishes "wide" Thomism,
which includes those who claim to follow the spirit and basic insights
of Aquinas and manifest an evident dependence on his texts, from
"eclectic" Thomism which includes those with a willingness to allow the
influence of other philosophical and theological systems in order to
relativize the principles and conclusions of traditional Thomism. John Haldane
gives an historic division of Thomism including 1) the period of
Aquinas and his first followers from the 13th to 15th centuries, a
second Thomism from the 16th to 18th centuries, and a Neo-Thomism from
the 19th to 20th centuries.
One might justifiably articulate other historical divisions on the
basis of shifts in perspective on Aquinas' work including the period
immediately following Aquinas' canonization in 1325, the period
following the Council of Trent, and the period after the Second Vatican
Council. Romanus Cessario thinks it better not to identify intervals of
time or periods within the larger history of Thomism because Thomists
have addressed such a broad variety of issues and in too many
geographical areas to permit such divisions.
First Thomistic School
The
first period of Thomism stretches from Aquinas' teaching activity
beginning in 1256 at Paris to Cologne, Orvieto, Viterbo, Rome, and
Naples until his canonization in 1325. In this period his doctrines
"were both attacked and defended" as for example after his death (1274)
the condemnations of 1277, 1284 and 1286 were counteracted by the
General Chapters of the Dominican Order and other disciples who came to Aquinas' defense.
Council of Trent to Aeterni Patris
Responding
to prevailing philosophical rationalism during the Enlightenment
Salvatore Roselli, professor of theology at the College of St. Thomas,
the future Pontifical University of Saint Thomas Aquinas, Angelicum in Rome, published a six volume Summa philosophica (1777) giving an Aristotelian interpretation of Aquinas validating the senses as a source of knowledge. While teaching at the College Roselli is considered to have laid the foundation for Neothomism in the nineteenth century.
According to historian J.A. Weisheipl in the late 18th and early 19th
centuries "everyone who had anything to do with the revival of Thomism
in Italy, Spain and France was directly influenced by Roselli’s
monumental work.
Aeterni Patris to Vatican II
The Thomist revival that began in the mid-19th century, sometimes
called "neo-scholasticism" or "neo-Thomism," can be traced to figures
such as Angelicum professor Tommaso Maria Zigliara, JesuitsJosef Kleutgen, and Giovanni Maria Cornoldi, and secular priestGaetano Sanseverino. This movement received impetus from Pope Leo XIII's encyclicalAeterni Patris of 1879. Generally the revival accepts the interpretative tradition of Aquinas' great commentators such as Capréolus, Cajetan, and John of St. Thomas.
Its focus, however, is less exegetical and more concerned with carrying
out the program of deploying a rigorously worked out system of
Thomistic metaphysics in a wholesale critique of modern philosophy.
Other seminal figures in the early part of the century include Martin Grabmann (1875-1949) and Amato Masnovo (1880-1955). The movement's core philosophical commitments are summarized in "Twenty-Four Thomistic Theses" approved by Pope Pius X. In the first half of the twentieth century Angelicum professors Edouard Hugon, Réginald Garrigou-Lagrange among others, carried on Leo's call for a Thomist revival. Their approach is reflected in many of the manuals and textbooks widely in use in Roman Catholic colleges and seminaries before Vatican II.
While the Second Vatican Council took place from 1962-1965 Cornelio Fabro
was already able to write in 1949 that the century of revival with its
urgency to provide a synthetic systematization and defense of Aquinas'
thought was coming to an end. Fabro looked forward to a more
constructive period in which the original context of Aquinas' thought
would be explored.
Recent schools and interpretations
A summary of some recent and current schools and interpretations of Thomism can be found, among other places, in La Metafisica di san Tommaso d'Aquino e i suoi interpreti (2002), by Battista Mondin, Being and Some 20th Century Thomists (2003), by John F. X. Knasas as well as in the writing of Edward Feser.
Neo-Scholastic Thomism
Neo-Scholastic Thomism
identifies with the philosophical and theological tradition stretching
back to the time of St. Thomas. In the nineteenth century authors such
as Tommaso Maria Zigliara
focused not only on exegesis of the historical Aquinas but also on the
articulation of a rigorous system of orthodox Thomism to be used as an
instrument of critique of contemporary thought. Due to its suspicion of
attempts to harmonize Aquinas with non-Thomistic categories and
assumptions, Neo-Scholastic Thomism has sometimes been called "strict observance Thomism." A discussion of recent and current Neo-Scholastic Thomism can be found in La Metafisica di san Tommaso d'Aquino e i suoi interpreti (2002) by Battista Mondin, which includes such figures as Martin Grabmann, Reginald Garrigou-Lagrange, Sofia Vanni Rovighi (1908–1990), Cornelio Fabro (1911–1995), Carlo Giacon (1900–1984), Tomáš Týn (1950–1990), Abelardo Lobato (1925–2012), Leo Elders (b. 1926) and Giovanni Ventimiglia (b. 1964) among others. Fabro in particular emphasizes Aquinas' originality, especially with respect to the actus essendi
or act of existence of finite beings by participating in being itself.
Other scholars such as those involved with the "Progetto Tommaso" seek to establish an objective and universal reading of Aquinas' texts.
Cracow Circle Thomism
Cracow Circle Thomism (named after Cracow) has been called "the most significant expression of Catholic thought between the two World Wars."
The Circle was founded by a group of philosophers and theologians that
in distinction to more traditional Neo-Scholastic Thomism embraced
modern formal logic as an analytical tool for traditional Thomist
philosophy and theology.
Inspired by the logical clarity of Aquinas, members of the Circle held
both philosophy and theology to contain "propositions with
truth-values…a structured body of propositions connected in meaning and
subject matter, and linked by logical relations of compatibility and
incompatibility, entailment etc." "The Cracow Circle set about
investigating and where possible improving this logical structure with
the most advanced logical tools available at the time, namely those of
modern mathematical logic, then called 'logistic'." Perhaps the most famous exponent of the Cracow Circle is Józef Maria Bocheński, author of A History of Formal Logic (1961), and one of the preeminent twentieth-century historians of logic. Bocheński completed a doctorate in theology at the Pontifical University of Saint Thomas Aquinas, Angelicum in 1934 where he taught logic until 1940. Other members included Jan Salamucha and Jan F. Drewnowski.
Existential Thomism
Étienne Gilson (1884–1978), the key proponent of existential Thomism,
tended to emphasize the importance of historical exegesis but also to
deemphasize Aquinas's continuity with the Aristotelian tradition, and
like Cornelio Fabro
of the Neo-scholastic school, to highlight the originality of Aquinas's
doctrine of being as existence. He was also critical of the
Neo-Scholastics' focus on the tradition of the commentators, and given
what he regarded as their insufficient emphasis on being or existence
accused them of "essentialism"
(to allude to the other half of Aquinas's distinction between being and
essence). Gilson's reading of Aquinas as putting forward a
distinctively "Christian philosophy" tended, at least in the view of his
critics, to blur Aquinas's distinction between philosophy and theology. Jacques Maritain
(1882–1973) introduced into Thomistic metaphysics the notion that
philosophical reflection begins with an "intuition of being," and in
ethics and social philosophy sought to harmonize Thomism with personalism and pluralistic democracy. Though "existential Thomism" was sometimes presented as a counterpoint to modern existentialism,
the main reason for the label is the emphasis this approach puts on
Aquinas's doctrine of existence. Contemporary proponents include Joseph Owens and John F. X. Knasas.
River Forest Thomism
According to River Forest Thomism (named after River Forest, Illinois), the natural sciences are epistemologically prior to metaphysics, preferably called metascience.
This approach emphasizes the Aristotelian foundations of Aquinas's
philosophy, and in particular the idea that the construction of a sound
metaphysics must be preceded by a sound understanding of natural
science, as interpreted in light of an Aristotelian philosophy of
nature. Accordingly, it is keen to show that modern physical science can
and should be given such an interpretation. Charles De Koninck (1906–1965), Raymond Jude Nogar (1915–1966), James A. Weisheipl (1923–1984), William A. Wallace, and Benedict Ashley, are among its representatives. It is sometimes called "Laval Thomism" after the University of Laval
in Quebec, where De Koninck was a professor. The alternative label
"River Forest Thomism" derives from a suburb of Chicago, the location of
the Albertus Magnus Lyceum for Natural Science, whose members have been associated with this approach. It is also sometimes called "Aristotelian Thomism"
(to highlight its contrast with Gilson's brand of existential Thomism)
though since Neo-Scholastic Thomism also emphasizes Aquinas's continuity
with Aristotle, this label seems a bit too proprietary. (There are
writers, like the contemporary Thomist Ralph McInerny who have exhibited both Neo-Scholastic and Laval/River Forest influences, and the approaches are not necessarily incompatible.)
Transcendental Thomism
Unlike the first three schools mentioned above, transcendental Thomism, associated with Joseph Maréchal (1878–1944), Karl Rahner (1904–84), and Bernard Lonergan (1904–84), does not oppose modern philosophy wholesale, but seeks to reconcile Thomism with a Cartesian subject-centered approach to knowledge in general, and Kantiantranscendental philosophy
in particular. It seems fair to say that most Thomists otherwise
tolerant of diverse approaches to Aquinas's thought tend to regard
transcendental Thomism as having conceded too much to modern philosophy
genuinely to count as a variety of Thomism, strictly speaking, and this
school of thought has in any event been far more influential among
theologians than among philosophers.
Lublin Thomism
Lublin Thomism, which derives its name from the Catholic University of Lublin in Poland where it is centered, is also sometimes called "phenomenological Thomism."
Like transcendental Thomism, it seeks to combine Thomism with certain
elements of modern philosophy. In particular, it seeks to make use of
the phenomenological method of philosophical analysis associated with Edmund Husserl and the ethical personalism of writers like Max Scheler in articulating the Thomist conception of the human person. Its best-known proponent is Karol Wojtyla (1920–2005), who went on to become Pope John Paul II.
However, unlike transcendental Thomism, the metaphysics of Lublin
Thomism places priority on existence (as opposed to essence), making it
an existential Thomism that demonstrates consonance with the Thomism of
Étienne Gilson. It should be noted that the phenomenological concerns
of the Lublin school are not metaphysical in nature as this would
constitute idealism.
Rather, they are considerations which are brought into relation with
central positions of the school, such as when dealing with modern
science, its epistemological value, and its relation to metaphysics.
Analytical Thomism
Analytical Thomism described by John Haldane,
its key proponent, as "a broad philosophical approach that brings into
mutual relationship the styles and preoccupations of recent
English-speaking philosophy and the concepts and concerns shared by
Aquinas and his followers" (from the article on "analytical Thomism" in The Oxford Companion to Philosophy, edited by Ted Honderich). By "recent English-speaking philosophy" Haldane means the analytical tradition founded by thinkers like Gottlob Frege, Bertrand Russell, G. E. Moore, and Ludwig Wittgenstein, which tends to dominate academic philosophy in the English-speaking world. Elizabeth Anscombe (1919–2001) and her husband Peter Geach
are sometimes considered the first "analytical Thomists," though (like
most writers to whom this label has been applied) they did not describe
themselves in these terms, and as Haldane's somewhat vague expression
"mutual relationship" indicates, there does not seem to be any set of
doctrines held in common by all analytical Thomists. What they do have
in common seems to be that they are philosophers trained in the analytic
tradition who happen to be interested in Aquinas in some way; and the
character of their "analytical Thomism" is determined by whether it
tends to stress the "analytical" side of analytical Thomism, or the
"Thomism" side, or, alternatively, attempts to emphasize both sides
equally.
