Instinct or innate behavior is the inherent inclination of a livingorganism towards a particular complex behavior. The simplest example of an instinctive behavior is a fixed action pattern
(FAP), in which a very short to medium length sequence of actions,
without variation, are carried out in response to a corresponding
clearly defined stimulus.
Any behavior is instinctive if it is performed without being based upon prior experience (that is, in the absence of learning), and is therefore an expression of innate biological factors. Sea turtles, newly hatched on a beach, will instinctively move toward the ocean. A marsupial climbs into its mother's pouch upon being born. Honeybees
communicate by dancing in the direction of a food source without formal
instruction. Other examples include animal fighting, animal courtship behavior, internal escape functions, and the building of nests.
Though an instinct is defined by its invariant innate characteristics,
details of its performance can be changed by experience; for example, a
dog can improve its fighting skills by practice.
An instinctive behavior of shaking water from wet fur
Instincts are inborn complex patterns of behavior that exist in most members of the species, and should be distinguished from reflexes,
which are simple responses of an organism to a specific stimulus, such
as the contraction of the pupil in response to bright light or the
spasmodic movement of the lower leg when the knee is tapped. The absence
of volitional capacity must not be confused with an inability to modify
fixed action patterns. For example, people may be able to modify a
stimulated fixed action pattern by consciously recognizing the point of
its activation and simply stop doing it, whereas animals without a
sufficiently strong volitional capacity may not be able to disengage
from their fixed action patterns, once activated.
Instinctual behaviour in humans has been studied, and is a controversial topic.
Jean Henri Fabre (1823-1915), an entomologist, considered instinct to be any behavior which did not require cognition or consciousness
to perform. Fabre's inspiration was his intense study of insects, some
of whose behaviors he wrongly considered fixed and not subject to
environmental influence.
Instinct as a concept fell out of favor in the 1920s with the rise of behaviorism and such thinkers as B. F. Skinner, which held that most significant behavior is learned.
An interest in innate behaviors arose again in the 1950s with Konrad Lorenz and Nikolaas Tinbergen,
who made the distinction between instinct and learned behaviors. Our
modern understanding of instinctual behavior in animals owes much to
their work. For instance, there exists a sensitive period for a bird in
which it learns the identity of its mother. Konrad Lorenz famously had a
goose imprint
on his boots. Thereafter the goose would follow whoever wore the boots.
This suggests that the identity of the goose's mother was learned, but
the goose's behavior towards what it perceived as its mother was
instinctive.
In psychology
The term "instinct" in psychology was first used in the 1870s by Wilhelm Wundt.
By the close of the 19th century, most repeated behavior was considered
instinctual. In a survey of the literature at that time, one
researcher chronicled 4,000 human "instincts," having applied this label to any behavior that was repetitive. In the early twentieth century, there was recognized a "union of instinct and emotion".
William McDougall held that many instincts have their respective associated specific emotions.
As research became more rigorous and terms better defined, instinct as
an explanation for human behavior became less common. In 1932, McDougall
argued that the word 'instinct' is more suitable for describing animal
behaviour, while he recommended the word 'propensity'
for goal directed combinations of the many innate human abilities,
which are loosely and variably linked, in a way that shows strong plasticity. In a conference in 1960, chaired by Frank Beach, a pioneer in comparative psychology, and attended by luminaries in the field, the term 'instinct' was restricted in its application.
During the 1960s and 1970s, textbooks still contained some discussion
of instincts in reference to human behavior. By the year 2000, a survey
of the 12 best selling textbooks in Introductory Psychology revealed
only one reference to instincts, and that was in regard to Sigmund Freud's referral to the "id" instincts.In this sense, the term 'instinct' appeared to have become outmoded for introductory textbooks on human psychology.
Sigmund Freud considered that mental images of bodily needs, expressed in the form of desires, are called instincts.
In the 1950s, the psychologist Abraham Maslow
argued that humans no longer have instincts because we have the ability
to override them in certain situations. He felt that what is called
instinct is often imprecisely defined, and really amounts to strong drives.
For Maslow, an instinct is something which cannot be overridden, and
therefore while the term may have applied to humans in the past, it no
longer does.
The book Instinct: an enduring problem in psychology (1961) selected a range of writings about the topic.
In a classic paper published in 1972, the psychologist Richard Herrnstein wrote: "A comparison of McDougall's theory of instinct and Skinner's reinforcement theory
— representing nature and nurture — shows remarkable, and largely
unrecognized, similarities between the contending sides in the nature-nurture dispute as applied to the analysis of behavior."
F.B. Mandal proposed a set of criteria by which a behavior might
be considered instinctual: a) be automatic, b) be irresistible, c)
occur at some point in development, d) be triggered by some event in the
environment, e) occur in every member of the species, f) be
unmodifiable, and g) govern behavior for which the organism needs no
training (although the organism may profit from experience and to that
degree the behavior is modifiable).
In Information behavior: An Evolutionary Instinct (2010,
pp. 35–42), Amanda Spink notes that "currently in the behavioral
sciences instinct is generally understood as the innate part of behavior
that emerges without any training or education in humans." She claims
that the viewpoint that information behavior has an instinctive basis is
grounded in the latest thinking on human behavior. Furthermore, she
notes that "behaviors such as cooperation, sexual behavior, child
rearing and aesthetics are [also] seen as 'evolved psychological
mechanisms' with an instinctive basis." Spink adds that Steven Pinker similarly asserts that language acquisition is instinctive in humans in his book The Language Instinct (1994). In 1908, William McDougall wrote about the "instinct of curiosity" and its associated "emotion of wonder", though Spink's book does not mention this.
M.S. Blumberg in 2017 examined the use of the word instinct, and found it varied significantly.
In humans
The existence of simplest instincts in humans is a widely debated topic.
Congenital fear of snakes and spiders was found in six-month-old babies.
Infant cry
is a manifestation of instinct. The infant cannot otherwise protect
itself for survival during its long period of maturation. The maternal instinct,
manifest particularly in response to the infant cry, has long been
respected as one of the most powerful. Its mechanism has been partly
elucidated by observations with functional MRI of the mother’s brain.
Testosterone (main male sex hormone) primes several instincts, especially sexuality; also dominance, manifest in self-affirmation, the urge to win over rivals (see competitiveness), to dominate a hierarchy (see dominance hierarchy), and to respond to violent signals in men (see aggression), with weakening of empathy. In men, a decrease in testosterone level after the birth of a child in the family was found, so that the father's energies are more directed to nurturing, protecting and caring for the child. Unduly high levels of this hormone are often associated in a person with aggressiveness, illegal behavior, violence against others, such phenomena as banditry, etc. This is confirmed by studies conducted in prisons. The amount of testosterone in men may increase dramatically in response to any competition.
Squeamishness and disgust in humans is an instinct developed during evolution to protect the body and avoid infection by various diseases.
A real gecko hunts the pointer of a mouse, confused with prey.
Examples of behaviors that do not require conscious will include many
reflexes. The stimulus in a reflex may not require brain activity but
instead may travel to the spinal cord as a message that is then
transmitted back through the body, tracing a path called the reflex arc. Reflexes are similar to fixed action patterns
in that most reflexes meet the criteria of a FAP. However, a fixed
action pattern can be processed in the brain as well; a male stickleback's
instinctive aggression towards anything red during his mating season is
such an example. Examples of instinctive behaviors in humans include
many of the primitive reflexes, such as rooting and suckling, behaviors which are present in mammals.
In rats, it has been observed that innate responses are related to
specific chemicals, and these chemicals are detected by two organs
located in the nose: the vomeronasal organ (VNO) and the main olfactory
epithelium (MOE).
Maturational
Some
instinctive behaviors depend on maturational processes to appear. For
instance, we commonly refer to birds "learning" to fly. However, young
birds have been experimentally reared in devices that prevent them from
moving their wings until they reached the age at which their cohorts
were flying. These birds flew immediately and normally when released,
showing that their improvement resulted from neuromuscular maturation
and not true learning.
In evolution
Imprinting provides one example of instinct.
This complex response may involve visual, auditory, and olfactory cues
in the environment surrounding an organism. In some cases, imprinting
attaches an offspring to its parent, which is a reproductive benefit to
offspring survival.
If an offspring has attachment to a parent, it is more likely to stay
nearby under parental protection. Attached offspring are also more
likely to learn from a parental figure when interacting closely.
(Reproductive benefits are a driving force behind natural selection.)
Environment is an important factor in how innate behavior has evolved. A hypothesis of Michael McCollough, a positive psychologist,
explains that environment plays a key role in human behaviors such as
forgiveness and revenge. This hypothesis theorizes that various social
environments cause either forgiveness or revenge to prevail. McCollough
relates his theory to game theory.
In a tit-for-tat strategy, cooperation and retaliation are comparable
to forgiveness and revenge. The choice between the two can be beneficial
or detrimental, depending on what the partner-organism chooses. Though
this psychological example of game theory does not have such directly
measurable results, it provides an interesting theory of unique thought.
From a more biological standpoint, the brain's limbic system
operates as the main control-area for response to certain stimuli,
including a variety of instinctual behavior. The limbic system processes
external stimuli related to emotions, social activity, and motivation,
which propagates a behavioral response. Some behaviors include maternal
care, aggression, defense, and social hierarchy. These behaviors are
influenced by sensory input — sight, sound, touch, and smell.
Within the circuitry of the limbic system, there are various
places where evolution could have taken place, or could take place in
the future. For example, many rodents have receptors in the vomeronasal organ
that respond explicitly to predator stimuli that specifically relate to
that individual species of rodent. The reception of a predatory
stimulus usually creates a response of defense or fear. Mating in rats follows a similar mechanism. The vomeronasal organ and the main olfactory epithelium, together called the olfactory system,
detect pheromones from the opposite sex. These signals then travel to
the medial amygdala, which disperses the signal to a variety of brain
parts. The pathways involved with innate circuitry are extremely
specialized and specific. Various organs and sensory receptors play parts in this complex process.
Instinct is a phenomenon that can be investigated from a
multitude of angles: genetics, limbic system, nervous pathways, and
environment. Researchers can study levels of instincts, from molecular
to groups of individuals. Extremely specialized systems have evolved,
resulting in individuals which exhibit behaviors without learning them.
Human nature is a concept that denotes the fundamental dispositions and characteristics—including ways of thinking, feeling, and acting—that humans are said to have naturally. The term is often used to denote the essence of humankind, or what it 'means' to be human. This usage has proven to be controversial in that there is dispute as to whether or not such an essence actually exists.
Arguments about human nature have been a central focus of philosophy for centuries and the concept continues to provoke lively philosophical debate. While both concepts are distinct from one another, discussions
regarding human nature are typically related to those regarding the
comparative importance of genes and environment in human development (i.e., 'nature versus nurture'). Accordingly, the concept also continues to play a role in fields of science, such as neuroscience, psychology, and social science (such as sociology), in which various theorists claim to have yielded insight into human nature. Human nature is traditionally contrasted with human attributes that vary among societies, such as those associated with specific cultures.
The concept of nature as a standard by which to make judgments is traditionally said to have begun in Greek philosophy, at least in regard to its heavy influence on Western and Middle Eastern languages and perspectives. By late antiquity and medieval times, the particular approach that came to be dominant was that of Aristotle's teleology,
whereby human nature was believed to exist somehow independently of
individuals, causing humans to simply become what they become. This, in
turn, has been understood as also demonstrating a special connection
between human nature and divinity, whereby human nature is understood in terms of final and formalcauses.
More specifically, this perspective believes that nature itself (or a
nature-creating divinity) has intentions and goals, including the goal
for humanity to live naturally. Such understandings of human nature see
this nature as an "idea", or "form" of a human. However, the existence of this invariable and metaphysical human nature is subject of much historical debate, continuing into modern times.
Against Aristotle's notion of a fixed human nature, the relative
malleability of man has been argued especially strongly in recent
centuries—firstly by early modernists such as Thomas Hobbes and Jean-Jacques Rousseau. In his Emile, or On Education, Rousseau wrote: "We do not know what our nature permits us to be." Since the early 19th century, such thinkers as Hegel, Marx, Kierkegaard, Nietzsche, and Sartre, as well as structuralists and postmodernists more generally, have also sometimes argued against a fixed or innate human nature.
Charles Darwin's theory of evolution
has particularly changed the shape of the discussion, supporting the
proposition that mankind's ancestors were not like mankind today. Still,
more recent scientific perspectives—such as behaviorism, determinism, and the chemical model within modern psychiatry
and psychology—claim to be neutral regarding human nature. As in much
of modern science, such disciplines seek to explain with little or no
recourse to metaphysical causation.
They can be offered to explain the origins of human nature and its
underlying mechanisms, or to demonstrate capacities for change and
diversity which would arguably violate the concept of a fixed human
nature.
Classical Greek philosophy
Philosophy in classical Greece is the ultimate origin of the Western conception of the nature of things.
According to Aristotle, the philosophical study of human nature itself originated with Socrates, who turned philosophy from study of the heavens to study of the human things.
Though leaving no written works, Socrates is said to have studied the
question of how a person should best live. It is clear from the works of
his students, Plato and Xenophon, and also from the accounts of Aristotle (Plato's student), that Socrates was a rationalist and believed that the best life and the life most suited to human nature involved reasoning. The Socratic school was the dominant surviving influence in philosophical discussion in the Middle Ages, amongst Islamic, Christian, and Jewish philosophers.
The human soul
in the works of Plato and Aristotle has a nature that is divided in a
specifically human way. One part is specifically human and rational,
being further divided into (1) a part which is rational on its own; and
(2) a spirited part which can understand reason. Other parts of the
soul are home to desires or passions similar to those found in animals.
In both Aristotle and Plato, spiritedness (thumos) is distinguished from the other passions (epithūmíā).
The proper function of the "rational" was to rule the other parts of
the soul, helped by spiritedness. By this account, using one's reason is
the best way to live, and philosophers are the highest types of humans.
Aristotle
Aristotle—Plato's
most famous student-made some of the most famous and influential
statements about human nature. In his works, apart from using a similar
scheme of a divided human soul, some clear statements about human nature
are made:
Man is a conjugal animal: An animal that is born to couple in adulthood. In doing so, man builds a household (oikos) and, in more successful cases, a clan or small village still run upon patriarchal lines.
Man is a political animal: An animal with an innate propensity to develop more complex communities (i.e. the size of a city or town), with systems of law-making and a division of labor. This type of community is different in kind from a large family, and requires the special use of human reason.
Man is a mimetic animal: Man loves to use his imagination, and not only to make laws and run town councils:
"[W]e enjoy looking at accurate likenesses of things which are
themselves painful to see, obscene beasts, for instance, and corpses.…
[The] reason why we enjoy seeing likenesses is that, as we look, we
learn and infer what each is, for instance, 'that is so and so.'"
For Aristotle, reason is not only what is most special about humanity
compared to other animals, but it is also what we were meant to achieve
at our best. Much of Aristotle's description of human nature is still
influential today. However, the particular teleological idea that humans
are "meant" or intended to be something has become much less popular in
modern times.
Theory of four causes
For the Socratics, human nature, and all natures, are metaphysical concepts. Aristotle developed the standard presentation of this approach with his theory of four causes, whereby every living thing exhibits four aspects, or "causes:"
For example, an oak tree
is made of plant cells (matter); grows from an acorn (effect); exhibits
the nature of oak trees (form); and grows into a fully mature oak tree
(end). According to Aristotle, human nature is an example of a formal
cause. Likewise, our 'end' is to become a fully actualized human being (including fully actualizing the mind). Aristotle suggests that the human intellect (νοῦς, noûs), while "smallest in bulk", is the most significant part of the human psyche and should be cultivated above all else. The cultivation of learning and intellectual growth of the philosopher is thereby also the happiest and least painful life.
Mencius argues that human nature is good, understanding human nature as the innate tendency to an ideal state that's expected to be formed under the right conditions. Therefore, humans have the capacity to be good, even though they are not all good.
According to Mencian theory, human nature contains four beginnings (端; duan) of morality:
The beginnings of morality are characterized by both affective motivations and intuitive judgments, such as what's right and wrong, deferential, respectful, or disdainful.
In Mencius' view, goodness is the result of the development of
innate tendencies toward the virtues of benevolence, righteousness,
wisdom, and propriety. The tendencies are manifested in moral emotions for every human being. Reflection (思; si) upon the manifestations of the four beginnings leads to the development of virtues. It brings recognition that virtue takes precedence over satisfaction, but a lack of reflection inhibits moral development. In other words, humans have a constitution comprising emotional predispositions that direct them to goodness.
Mencius also addresses the question why the capacity for evil is not grounded in human nature.
If an individual becomes bad, it is not the result of his or her
constitution, as their constitution contains the emotional
predispositions that direct to goodness, but a matter of injuring or not
fully developing his or her constitution in the appropriate direction. He recognizes desires of the senses as natural predispositions distinct from the four beginnings. People can be misled and led astray by their desires if they do not engage their ethical motivations. He therefore places responsibility on people to reflect on the manifestations of the four beginnings.
Herein, it is not the function of ears and eyes but the function of the
heart to reflect, as sensory organs are associated with sensual desires
but the heart is the seat of feeling and thinking.
Mencius considers core virtues—benevolence, righteousness, propriety,
and wisdom—as internal qualities that humans originally possess, so
people can not attain full satisfaction by solely pursuits of
self-interest due to their innate morality.
Wong (2018) underscores that Mencius' characterization of human nature
as good means that "it contains predispositions to feel and act in
morally appropriate ways and to make intuitive normative judgments that
can with the right nurturing conditions give human beings guidance as to
the proper emphasis to be given to the desires of the senses."
Mencius sees ritual (i.e., the standard for how humans should
treat and interact with each other) as an outward expression of the
inherent moral sense in human nature.
Xunzi
Mencius' view of ritual is in contrast to Xunzi, who does not view moral sense as an innate part of human nature. Rather, a moral sense is acquired through learning, in which one engages in and reflects upon a set of ritual practices.
Xunzi's claim that human nature is bad, according to Ivanhoe (1994),
means that humans do not have a conception of morality and therefore
must acquire it through learning, lest destructive and alienating
competition inevitably arises from human desire.
Xunzi understands human nature as the basic faculties, capacities, and desires that people have from birth. He argues that human nature is evil and that any goodness is the result of human activity. It is human nature to seek profit, because humans desire for sensory satisfaction.
Xunzi states that "Now the nature of man is evil. It must depend on
teachers and laws to become correct and achieve propriety and
righteousness and then it becomes disciplined." He underscores that goodness comes from the traits and habits acquired through conscious actions, which he calls artifice (偽; wei). Therefore, morality is seen as a human artifice but not as a part of human nature.
Legalism
Statue of Shang Yang, a prominent Legalist scholar and statesman
Human nature is one of the major pillars of Legalism in China.
However, Legalists do not concern themselves with whether human
goodness or badness is inborn, and whether human beings possess the
fundamental qualities associated with that nature.
Legalists see the overwhelming majority of human beings as selfish in nature. They hold the view that human nature is evil, in which individuals are driven by selfishness. Therefore, people are not expected to always behave morally.
For instance, due to the corrupt nature of humans, Legalists did not
trust that officials would carry out their duties in a fair and
impartial manner.
There is a perpetual political struggle, characterized by conflict
among contending human actors and interests, where individuals are
easily tempted due to their selfish nature at the expense of others.
According to Legalism, selfishness in human nature can not be eliminated or altered by education or self-cultivation.
It dismisses the possibility that people can overcome their selfishness
and considers the possibility that people can be driven by moral
commitment to be exceptionally rare. Legalists do not see the individual morality of both the rulers or the ruled as an important concern in a political system. Instead, Legalist thinkers such as Han Fei emphasize clear and impersonal norms and standards (such as laws, regulations, and rules) as the basis to maintain order.
As human nature has an unchanging selfish but satiable core, Han Fei argues that competition for external goods during times of scarcity
produces disorder, while times of abundance simply mean that people do
not fall back into chaos and conflict but not that they are necessarily
nice.
Additionally, Han Fei argues that people are all motivated by their
unchanging selfish core to want whatever advantage they can gain from
whomever they can gain such advantage, which especially comes to
expression in situations where people can act with impunity.
Legalists posit that human selfishness can be an asset rather than a threat to a state.
It is axiomatic in Legalism that the government can not be staffed by
upright and trustworthy men of service, because every member of the
elite—like any member of society—will pursue their own interests and
thus must be employed for their interests.
Herein, individuals must be allowed to pursue their selfish interests
exclusively in a manner that benefits rather than contradicts the needs
of a state. Therefore, a political system that presupposes this human selfishness is the only viable system.
In contrast, a political system based on trust and respect (rather than
impersonal norms and standards) brings great concern with regard to an
ongoing and irresolvable power struggle.
Rather, checks and controls must be in place to limit the subversion of
the system by its actors (such as ministers and other officials).
Legalists view the usage of reward and punishment as effective
political controls, as it is in human nature to have likes and dislikes. For instance, according to the Legalist statesman Shang Yang, it is crucial to investigate the disposition of people in terms of rewards and penalties when a law is established.
He explains that a populace can not be driven to pursuits of
agriculture or warfare if people consider these to be bitter or
dangerous on the basis of calculations about their possible benefits,
but people can be directed toward these pursuits through the application
of positive and negative incentives.
As an implication of the selfish core in human nature, Han Fei remarks
that "Those who act as ministers fear the penalties and hope to profit
by the rewards."
In Han Fei's view, the only realistic option is a political system that produces equivalents of junzi (君子, who are virtuous exemplars in Confucianism) but not junzi. This does not mean, however, that Han Fei makes a distinction between seeming and being good, as he does not entertain the idea that humans are good.
Rather, as human nature is constituted by self-interest, he argues that
humans can be shaped behaviorally to yield social order if it is in the
individual's own self-interest to abide by the norms (i.e., different
interests are aligned to each other and the social good), which is most efficiently ensured if the norms are publicly and impartially enforced.
Christian theology
In Christian theology, there are two ways of "conceiving human
nature:" The first is "spiritual, Biblical, and theistic"; and the
second is "natural, cosmical, and anti-theistic". The focus in this section is on the former. As William James put it in his study of human nature from a religious perspective, "religion" has a "department of human nature".
Various views of human nature have been held by theologians. However, there are some "basic assertions" in all "biblical anthropology:"
The Bible
contains no single "doctrine of human nature". Rather, it provides
material for more philosophical descriptions of human nature. For example, Creation as found in the Book of Genesis provides a theory on human nature.
Catechism of the Catholic Church, under the chapter "Dignity of the human person", provides an article about man as image of God, vocation to beatitude, freedom, human acts, passions, moral conscience, virtues, and sin.
Created human nature
As originally created, the Bible describes "two elements" in human
nature: "the body and the breath or spirit of life breathed into it by
God". By this was created a "living soul", meaning a "living person". According to Genesis 1:27, this living person was made in the "image of God". From the biblical perspective, "to be human is to bear the image of God."
"Two main modes of
conceiving human nature—the one of which is spiritual, Biblical, and
theistic," and the other "natural, cosmical, and anti-theistic." John Tulloch
Genesis does not elaborate the meaning of "the image of God", but
scholars find suggestions. One is that being created in the image of God
distinguishes human nature from that of the beasts.
Another is that as God is "able to make decisions and rule" so humans
made in God's image are "able to make decisions and rule". A third is
that mankind possesses an inherent ability "to set goals" and move
toward them. That God denoted creation as "good" suggests that Adam was "created in the image of God, in righteousness".
Adam was created with ability to make "right choices", but also
with the ability to choose sin, by which he fell from righteousness into
a state of "sin and depravity". Thus, according to the Bible, "humankind is not as God created it."
Fallen human nature
By Adam's fall into sin, "human nature" became "corrupt", although it retains the image of God. Both the Old Testament and the New Testament teach that "sin is universal." For example, Psalm 51:5 reads: "For behold I was conceived in iniquities; and in sins did my mother conceive me." Jesus taught that everyone is a "sinner naturally" because it is mankind's "nature and disposition to sin". Paul, in Romans 7:18, speaks of his "sinful nature".
Such a "recognition that there is something wrong with the moral nature of man is found in all religions."Augustine of Hippo coined a term for the assessment that all humans are born sinful: original sin. Original sin is "the tendency to sin innate in all human beings". The doctrine of original sin is held by the Catholic Church and most mainstream Protestant denominations, but rejected by the Eastern Orthodox Church, which holds the similar doctrine of ancestral fault.
"The corruption of original sin extends to every aspect of human
nature": to "reason and will" as well as to "appetites and impulses".
This condition is sometimes called "total depravity". Total depravity does not mean that humanity is as "thoroughly depraved" as it could become. Commenting on Romans 2:14, John Calvin writes that all people have "some notions of justice and rectitude ... which are implanted by nature" all people.
Adam embodied the "whole of human nature" so when Adam sinned "all of human nature sinned."
The Old Testament does not explicitly link the "corruption of human
nature" to Adam's sin. However, the "universality of sin" implies a link
to Adam. In the New Testament, Paul concurs with the "universality of
sin". He also makes explicit what the Old Testament implied: the link
between humanity's "sinful nature" and Adam's sin In Romans 5:19, Paul writes, "through [Adam's] disobedience humanity became sinful." Paul also applied humanity's sinful nature to himself: "there is nothing good in my sinful nature."
The theological "doctrine of original sin" as an inherent element
of human nature is not based only on the Bible. It is in part a
"generalization from obvious facts" open to empirical observation.
Empirical view
A
number of experts on human nature have described the manifestations of
original (i.e., the innate tendency to) sin as empirical facts.
Biologist Richard Dawkins, in his The Selfish Gene,
states that "a predominant quality" in a successful surviving gene is
"ruthless selfishness". Furthermore, "this gene selfishness will usually
give rise to selfishness in individual behavior."
Child psychologist Burton L. White finds a "selfish" trait in
children from birth, a trait that expresses itself in actions that are
"blatantly selfish".
Sociologist William Graham Sumner
finds it a fact that "everywhere one meets "fraud, corruption,
ignorance, selfishness, and all the other vices of human nature".
He enumerates "the vices and passions of human nature" as "cupidity,
lust, vindictiveness, ambition, and vanity". Sumner finds such human
nature to be universal: in all people, in all places, and in all
stations in society.
Psychiatrist Thomas Anthony Harris,
on the basis of his "data at hand", observes "sin, or badness, or evil,
or 'human nature', whatever we call the flaw in our species, is
apparent in every person." Harris calls this condition "intrinsic
badness" or "original sin".
Empirical discussion questioning the genetic exclusivity of such an intrinsic badness proposition is presented by researchers Elliott Sober and David Sloan Wilson. In their book, Unto Others: The Evolution and Psychology of Unselfish Behavior, they propose a theory of multilevel group selection in support of an inherent genetic "altruism" in opposition to the original sin exclusivity for human nature.
20th century Liberal Theology
Liberal theologians
in the early 20th century described human nature as "basically good",
needing only "proper training and education". But the above examples
document the return to a "more realistic view" of human nature "as
basically sinful and self-centered". Human nature needs "to be regenerated ... to be able to live the unselfish life".
Regenerated human nature
According to the Bible, "Adam's disobedience corrupted human nature" but God mercifully "regenerates". "Regeneration is a radical change" that involves a "renewal of our [human] nature". Thus, to counter original sin, Christianity purposes "a complete transformation of individuals" by Christ.
The goal of Christ's coming is that fallen humanity might be
"conformed to or transformed into the image of Christ who is the perfect
image of God", as in 2 Corinthians 4:4. The New Testament makes clear the "universal need" for regeneration. A sampling of biblical portrayals of regenerating human nature and the behavioral results follow.
being "transformed by the renewing of your minds" (Romans 12:2)
being transformed from one's "old self" (or "old man") into a "new self" (or "new man") (Colossians 3:9-10)
being transformed from people who "hate others" and "are hard to get
along with" and who are "jealous, angry, and selfish" to people who
are "loving, happy, peaceful, patient, kind, good, faithful, gentle, and
self-controlled" (Galatians 5:20-23)
being transformed from looking "to your own interests" to looking "to the interests of others" (Philippians 2:4)
Early modern philosophy
One of the defining changes that occurred at the end of the Middle Ages was the end of the dominance of Aristotelian philosophy, and its replacement by a new approach to the study of nature, including human nature. In this approach, all attempts at conjecture about formal and final causes were rejected as useless speculation.
Also, the term "law of nature" now applied to any regular and
predictable pattern in nature, not literally a law made by a divine
lawmaker, and, in the same way, "human nature" became not a special
metaphysical cause, but simply whatever can be said to be typical
tendencies of humans.
Although this new realism applied to the study of human life from the beginning—for example, in Machiavelli's works—the definitive argument for the final rejection of Aristotle was associated especially with Francis Bacon.
Bacon sometimes wrote as if he accepted the traditional four causes
("It is a correct position that "true knowledge is knowledge by causes."
And causes again are not improperly distributed into four kinds: the
material, the formal, the efficient, and the final") but he adapted
these terms and rejected one of the three:
But of
these the final cause rather corrupts than advances the sciences, except
such as have to do with human action. The discovery of the formal is
despaired of. The efficient and the material (as they are investigated
and received, that is, as remote causes, without reference to the latent
process leading to the form) are but slight and superficial, and
contribute little, if anything, to true and active science.
This line of thinking continued with René Descartes, whose new approach returned philosophy or science to its pre-Socratic focus upon non-human things. Thomas Hobbes, then Giambattista Vico, and David Hume all claimed to be the first to properly use a modern Baconian scientific approach to human things.
Hobbes famously followed Descartes in describing humanity as
matter in motion, just like machines. He also very influentially
described man's natural state (without science and artifice) as one
where life would be "solitary, poor, nasty, brutish and short". Following him, John Locke's philosophy of empiricism also saw human nature as a tabula rasa.
In this view, the mind is at birth a "blank slate" without rules, so
data are added, and rules for processing them are formed solely by our
sensory experiences.
Jean-Jacques Rousseau
pushed the approach of Hobbes to an extreme and criticized it at the
same time. He was a contemporary and acquaintance of Hume, writing
before the French Revolution and long before Darwin and Freud. He shocked Western civilization with his Second Discourse
by proposing that humans had once been solitary animals, without reason
or language or communities, and had developed these things due to
accidents of pre-history. (This proposal was also less famously made by
Giambattista Vico.) In other words, Rousseau argued that human nature
was not only not fixed, but not even approximately fixed compared to
what had been assumed before him. Humans are political, and rational,
and have language now, but originally they had none of these things.
This in turn implied that living under the management of human reason
might not be a happy way to live at all, and perhaps there is no ideal
way to live. Rousseau is also unusual in the extent to which he took the
approach of Hobbes, asserting that primitive humans were not even
naturally social. A civilized human is therefore not only imbalanced and
unhappy because of the mismatch between civilized life and human
nature, but unlike Hobbes, Rousseau also became well known for the
suggestion that primitive humans had been happier, "noble savages".
Rousseau's conception of human nature has been seen as the origin
of many intellectual and political developments of the 19th and 20th
centuries. He was an important influence upon Kant, Hegel, and Marx, and the development of German idealism, historicism, and romanticism.
What human nature did entail, according to Rousseau and the other
modernists of the 17th and 18th centuries, were animal-like passions
that led humanity to develop language and reasoning, and more complex
communities (or communities of any kind, according to Rousseau).
In contrast to Rousseau, David Hume was a critic of the
oversimplifying and systematic approach of Hobbes, Rousseau, and some
others whereby, for example, all human nature is assumed to be driven by
variations of selfishness. Influenced by Hutcheson and Shaftesbury,
he argued against oversimplification. On the one hand, he accepted
that, for many political and economic subjects, people could be assumed
to be driven by such simple selfishness, and he also wrote of some of
the more social aspects of "human nature" as something which could be
destroyed, for example if people did not associate in just societies. On
the other hand, he rejected what he called the "paradox of the
sceptics", saying that no politician could have invented words like "'honourable' and 'shameful,' 'lovely' and 'odious,' 'noble' and 'despicable'", unless there was not some natural "original constitution of the mind".
Hume—like Rousseau—was controversial in his own time for his modernist
approach, following the example of Bacon and Hobbes, of avoiding
consideration of metaphysical explanations for any type of cause and
effect. He was accused of being an atheist. He wrote:
We
needn't push our researches so far as to ask "Why do we have humanity,
i.e. a fellow-feeling with others?" It's enough that we experience this
as a force in human nature. Our examination of causes must stop
somewhere.
After Rousseau and Hume, the nature of philosophy and science
changed, branching into different disciplines and approaches, and the
study of human nature changed accordingly. Rousseau's proposal that
human nature is malleable became a major influence upon international
revolutionary movements of various kinds, while Hume's approach has been
more typical in Anglo-Saxon countries, including the United States.
According to Edouard Machery, the concept of human nature is an outgrowth of folk biology
and in particular, the concept of folk essentialism - the tendency of
ordinary people to ascribe essences to kinds. Machery argues that while
the idea that humans have an "essence" is a very old idea, the idea that
all humans have a unified human nature is relatively modern; for a long
time, people thought of humans as "us versus them" and thus did not
think of human beings as a unified kind.
Contemporary philosophy
The concept of human nature is a source of ongoing debate in contemporary philosophy, specifically within philosophy of biology, a subfield of the philosophy of science. Prominent critics of the concept – David L. Hull, Michael Ghiselin, and David Buller; see also – argue that human nature is incompatible with modern evolutionary biology.
Conversely, defenders of the concept argue that when defined in certain
ways, human nature is both scientifically respectable and meaningful. Therefore, the value and usefulness of the concept depends essentially
on how one construes it. This section summarizes the prominent
construals of human nature and outlines the key arguments from
philosophers on both sides of the debate.
Criticism of the concept of human nature (Hull)
Philosopher of science David L. Hull
has influentially argued that there is no such thing as human nature.
Hull's criticism is raised against philosophers who conceive human
nature as a set of intrinsic phenotypic traits (or characters) that are universal among humans, unique to humans, and definitive of what it is to be a member of the biological species Homo sapiens.
In particular, Hull argues that such "essential sameness of human
beings" is "temporary, contingent and relatively rare" in biology.
He argues that variation, insofar as it is the result of evolution, is
an essential feature of all biological species. Moreover, the type of
variation which characterizes a certain species in a certain historical
moment is "to a large extent accidental" He writes:
Periodically
a biological species might be characterized by one or more characters
which are both universally distributed among and limited to the
organisms belonging to that species, but such states of affairs are
temporary, contingent and relatively rare.
Hull
reasons that properties universally shared by all members of a certain
species are usually also possessed by members of other species, whereas
properties exclusively possessed by the members of a certain species are
rarely possessed by all members of that species. For these reasons, Hull observes that, in contemporary evolutionary taxonomy,
belonging to a particular species does not depend on the possession of
any specific intrinsic properties. Rather, it depends on standing in the
right kind of relations (relations of genealogy or interbreeding, depending on the precise species concept being used) to other members of the species. Consequently, there can be no intrinsic properties that define what it is to be a member of the species Homo sapiens.
Individual organisms, including humans, are part of a species by virtue
of their relations with other members of the same species, not shared
intrinsic properties.
According to Hull, the moral significance of his argument lies in
its impact on the biologically legitimate basis for the concept of
"human rights". While it has long been argued that there is a sound
basis for "human rights" in the idea that all human beings are
essentially the same, should Hull's criticism work, such a basis – at
least on a biological level – would disappear. Nevertheless, Hull does
not perceive this to be a fundamental for human rights, because people
can choose to continue respecting human rights even without sharing the
same human nature.
Defences of the concept of human nature
Several
contemporary philosophers have attempted to defend the notion of human
nature against charges that it is incompatible with modern evolutionary
biology by proposing alternative interpretations. They claim that the
concept of human nature continues to bear relevance in the fields of neuroscience and biology.
Many have proposed non-essentialist notions. Others have argued that,
even if Darwinism has shown that any attempt to base species membership
on "intrinsic essential properties" is untenable, essences can
still be "relational" – this would be consistent with the interbreeding,
ecological, and phylogenetic species concepts, which are accepted by modern evolutionary biology. These attempts aim to make Darwinism compatible with a certain conception of human nature which is stable across time.
"Nomological" account (Machery)
Philosopher of science Edouard Machery
has proposed that the above criticisms only apply to a specific
definition (or "notion") of human nature, and not to "human nature in
general". He distinguishes between two different notions:
An essentialist notion of human nature - "Human nature is
the set of properties that are separately necessary and jointly
sufficient for being a human." These properties are also usually
considered as distinctive of human beings. They are also intrinsic to humans and inherent to their essence.
A nomological notion of human nature - "Human nature is the
set of properties that humans tend to possess as a result of the
evolution of their species."
Machery clarifies that, to count as being "a result of evolution", a property must have an ultimate explanation in Ernst Mayr's
sense. It must be possible to explain the trait as the product of
evolutionary processes. Importantly, properties can count as part of
human nature in the nomological sense even if they are not universal
among humans and not unique to humans. In other words, nomological
properties need not be necessary nor sufficient for being human.
Instead, it is enough that these properties are shared by most humans,
as a result of the evolution of their species – they "need to be
typical". Therefore, human nature in the nomological sense does not define what it is to be a member of the species Homo sapiens. Examples of properties that count as parts of human nature on the nomological definition include: being bipedal, having the capacity to speak, having a tendency towards biparental investment in children, having fear reactions to unexpected noises.
Finally, since they are the product of evolution, properties belonging
to the nomological notion of human nature are not fixed, but they can
change over time.
Machery agrees with biologists and others philosophers of biology
that the essentialist notion of human nature is incompatible with
modern evolutionary biology: we cannot explain membership in the human
species by means of a definition or a set of properties. However, he
maintains that this does not mean humans have no nature, because we can
accept the nomological notion which is not a definitional notion.
Therefore, we should think of human nature as the many properties humans
have in common as a result of evolution.
Machery argues that notions of human nature can help explain why
that, while cultures are very diverse, there are also many constants
across cultures. For Machery, most forms of cultural diversity are in
fact diversity on a common theme; for example, Machery observes that the
concept of a kinship system is common across cultures but the exact
form it takes and the specifics vary between cultures.
Problems with the nomological account
Machery also highlights potential drawbacks of the nomological account.
One is that the nomological notion is a watered-down notion that cannot
perform many of the roles that the concept of human nature is expected
to perform in science and philosophy. The properties endowed upon humans
by the nomological account do not distinguish humans from other animals
or define what it is to be human. Machery pre-empts this objection by
claiming that the nomological concept of human nature still fulfils many
roles. He highlights the importance of a conception which picks out
what humans share in common which can be used to make scientific,
psychological generalizations about human-beings.
One advantage of such a conception is that it gives an idea of the
traits displayed by the majority of human beings which can be explained
in evolutionary terms.
Another potential drawback is that the nomological account of
human nature threatens to lead to the absurd conclusion that all
properties of humans are parts of human nature. According to the
nomological account, a trait is only part of human nature if it is a
result of evolution. However, there is a sense in which all human traits
are results of evolution. For example, the belief that water is wet is
shared by all humans. However, this belief is only possible because we
have, for example, evolved a sense of touch. It is difficult to separate
traits which are the result of evolution and those which are not.
Machery claims the distinction between proximate and ultimate explanation can do the work here: only some human traits can be given an ultimate explanation, he argues.
According to the philosopher Richard Samuels the account of human nature is expected to fulfill the five following roles:
an organizing function that demarks a territory of scientific inquiry
a descriptive function that is traditionally understood as specifying properties that are universal across and unique to human being
a causal explanatory function that offers causal explanation for occurring human behaviours and features
a taxonomic function that specifies possessing human nature as a necessary and sufficient criterion for belonging to the human species
Invariances that assume the understanding that human nature
is to some degree fixed, invariable or at least hard to change and
stable across time.
Samuels objects that Machery's nomological account fails to deliver
on the causal explanatory function, because it claims that superficial
and co-varying properties are the essence of human nature. Thus, human nature cannot be the underlying cause of these properties and accordingly cannot fulfill its causal explanatory role.
Philosopher Grant Ramsey
also rejects Machery's nomological account. For him, defining human
nature with respect to only universal traits fails to capture many
important human characteristics. Ramsey quotes the anthropologist Clifford Geertz,
who claims that "the notion that unless a cultural phenomenon is
empirically universal it cannot reflect anything about the nature of man
is about as logical as the notion that because sickle-cell anemia
is, fortunately, not universal, it cannot tell us anything about human
genetic processes. It is not whether phenomena are empirically common
that is critical in science...but whether they can be made to reveal the
enduring natural processes that underly them."
Following Geertz, Ramsey holds that the study of human nature should
not rely exclusively on universal or near-universal traits. There are
many idiosyncratic and particular traits of scientific interest.
Machery's account of human nature cannot give an account to such
differences between men and women as the nomological account only picks
out the common features within a species. In this light, the female
menstrual cycle which is a biologically an essential and useful feature
cannot be included in a nomological account of human nature.
Ramsey also objects that Machery uncritically adopts the innate-acquired dichotomy,
distinguishing between human properties due to enculturation and those
due to evolution. Ramsey objects that human properties do not just fall
in one of the two categories, writing that "any organismic property is
going to be due to both heritable features of the organism as well as
the particular environmental features the organism happens to encounter
during its life."
"Causal essentialist" account (Samuels)
Richard
Samuels, in an article titled "Science and Human Nature", proposes a
causal essentialist view that "human nature should be identified with a
suite of mechanisms, processes, and structures that causally explain
many of the more superficial properties and regularities reliably
associated with humanity." This view is "causal" because the mechanisms causally explain
the superficial properties reliably associated with humanity by
referencing the underlying causal structures the properties belong to.
For example, it is true that the belief that water is wet is shared by
all humans yet it is not in itself a significant aspect of human nature.
Instead, the psychological process that lead us to assign the word
"wetness" to water is a universal trait shared by all human beings. In
this respect, the superficial belief that water is wet reveals an
important causal psychological process which is widely shared by most
human beings. The explanation is also "essentialist"
because there is a core set of empirically discoverable cognitive
mechanism that count as part of the human nature. According to Samuels,
his view avoids the standard biological objections to human nature
essentialism.
Samuels argues that the theoretical roles of human nature
includes: organizing role, descriptive functions, causal explanatory
functions, taxonomic functions, and invariances.
In comparison with traditional essentialist view, the "causal
essentialist" view does not accomplish the taxonomic role of human
nature (the role of defining what it is to be human). He claims however,
that no conception could achieve this, as the fulfillment of the role
would not survive evolutionary biologists’ objections (articulated above
by in "Criticisms of the concept of human nature"). In comparison with
Machery's nomological conception, Samuels wants to restore the
causal-explanatory function of human nature. He defines the essence of
human nature as causal mechanisms and not as surface-level properties.
For instance, on this view, linguistic behaviour is not part of human
nature, but the cognitive mechanisms underpinning linguistic behaviour
might count as part of human nature.
"Life-history trait cluster" account (Ramsey)
Grant Ramsey proposes an alternative account of human nature, which he names the "life-history trait cluster" account.
This view stems from the recognition that the combination of a specific
genetic constitution with a specific environment is not sufficient to
determine how a life will go, i.e., whether one is rich, poor, dies old,
dies young, etc. Many ‘life histories’ are possible for a given
individual, each populated by a great number of traits. Ramsey defines
his conception of human nature in reference to the “pattern of trait
clusters within the totality of extant possible life-histories”.
In other words, there are certain life histories, i.e., possible routes
one's life can take, for example: being rich, being a PhD student, or
getting ill. Ramsey underlines the patterns behind these possible routes
by delving into the causes of these life histories. For example, one
can make the following claim: “Humans sweat when they get exhausted" or
one can also propose neurological claims such as “Humans secrete
Adrenaline when they are in flight-fight mode.” This approach enables
Ramsey to go beyond the superficial appearances and understand the
similarities/differences between individuals in a deeper level which
refers to the causal mechanisms (processes, structures and constraints
etc.) which lie beneath them. Once we list all the possible
life-histories of an individual, we can find these causal patterns and
add them together to form the basis of individual nature.
Ramsey's next argumentative manoeuvre is to point out that traits
are not randomly scattered across potential life histories; there are
patterns. “These patterns” he states “provide the basis for the notion
of individual and human nature”. While one's ‘individual nature’ consists of the pattern of trait
clusters distributed across that individual's set of possible life
histories, Human Nature, Ramsey defines as “the pattern of trait
clusters within the totality of extant human possible life histories”.
Thus, if we were to combine all possible life histories of all
individuals in existence we would have access to the trait distribution
patterns that constitute human nature.
Trait patterns, on Ramsey's account, can be captured in the form of conditional statements, such as "if female, you develop ovaries" or "if male, you develop testes."
These statements will not be true of all humans. Ramsey contends that
these statements capture part of human nature if they have a good
balance of pervasiveness (many people satisfy the antecedent of the conditional statement), and robustness (many people who satisfy the antecedent go on to satisfy the consequent).
Human nature and human enhancement
The contemporary debate between so-called “bioconservatives” and “transhumanists”
is directly related to the concept of human nature: transhumanists
argue that "current human nature is improvable through the use of
applied science and other rational methods."
Bioconservatives believe that the costs outweigh the benefits: in
particular, they present their position as a defense of human nature
which, according to them, is threatened by human enhancement
technologies. Although this debate is mainly of an ethical kind, it is
deeply rooted in the different interpretations of human nature, human
freedom, and human dignity (which, according to bioconservatives, is
specific to human beings, while transhumanists think that it can be
possessed also by posthumans). As explained by Allen Buchanan,
the literature against human enhancement is characterized by two main
concerns: that "enhancement may alter or destroy human nature" and that
"if enhancement alters or destroys human nature, this will undercut our
ability to ascertain the good," as "the good is determined by our
nature."
Bioconservatives include Jürgen Habermas, Leon Kass, Francis Fukuyama, and Bill McKibben.
Some of the reasons why they oppose (certain forms of) human
enhancement technology are to be found in the worry that such technology
would be “dehumanizing” (as they would undermine the human dignity
intrinsically built in our human nature). For instance, they fear that
becoming “posthumans” could pose a threat to “ordinary” humans or be harmful to posthumans themselves.
Jürgen Habermas makes the argument against the specific case of
genetic modification of unborn children by their parents, referred to as
“eugenic programming” by Habermas. His argument is two-folded: The most
immediate threat is on the “ethical freedom” of programmed individuals,
and the subsequent threat is on the viability of liberal democracy.
Reasoning of the former can be formulated as the following: Genetic programming
of desirable traits, capabilities and dispositions puts restrictions on
a person's freedom to choose a life of his own, to be the sole author of his existence. A genetically-programmed child may feel alienated
from his identity, which is now irreversibly co-written by human agents
other than himself. This feeling of alienation, resulted
from“contingency of a life's beginning that is not at [one's] disposal,”
makes it difficult for genetically-modified persons to perceive
themselves as moral agents
who can make ethical judgement freely and independently - that is,
without any substantial or definitive interference from another agent.
Habermas proposes a second threat - the undermining power of genetic
programming on the viability of democracy. The basis of liberal democracy,
Habermas rightfully claims, is the symmetrical and independent mutual
recognition among free, equal and autonomous persons. Genetic
programming jeopardizes this condition by irreversibly subjecting
children to permanent dependence on their parents, thus depriving them
of their perceived ability to be full citizens of the legal
community. This fundamental modification to human relationship erodes
the foundation of liberal democracy and puts its viability in danger.
The most famous proponent of transhumanism, on the other hand, is Oxford Swedish philosopher Nick Bostrom. According to Bostrom, "human enhancement technologies should be made widely available,"
as they would offer enormous potential for improving the lives of human
beings, without "dehumanizing" them: for instance, improving their
intellectual and physical capacities, or protecting them from suffering,
illnesses, aging, and physical and cognitive shortcomings.
In response to bioconservatives, transhumanists argue that expanding a
person's "capability set" would increase her freedom of choice, rather
than reducing it.
Allen Buchanan
has questioned the relevance of the concept of human nature to this
debate. In "Human Nature and Enhancement", he argued that good but also
bad characteristics are part of human nature, and that changing the
"bad" ones does not necessarily imply that the "good" ones will be
affected. Moreover, Buchanan argued that the way we evaluate the good is
independent of human nature: in fact, we can "make coherent judgements
about the defective aspects of human nature, and if those defects were
readied this need not affect our ability to judge what is good".
Buchanan's conclusion is that the debate on enhancement of human beings
would be more fruitful if it was conducted without appealing to the
concept of human nature.
Tim Lewens
presented a similar position: since the only notions of human nature
which are compatible with biology offer "no ethical guidance in debates
over enhancement", we should set the concept of human nature aside when
debating about enhancement. On the other hand, "folk", neo-Aristotelian
conceptions of human nature seem to have normative implications, but
they have no basis in scientific research.
Grant Ramsey replied to these claims, arguing that his "life-history
trait cluster" account allows the concept of human nature "to inform
questions of human enhancement".
Appeals to nature often fall foul of the naturalistic fallacy, whereby certain capacities or traits are considered morally 'good' in virtue of their naturalness. The fallacy was initially introduced by G. E. Moore in 1903, who challenged philosopher's attempts to define good reductively, in terms of natural properties (such as desirable).
Reliance on 'the natural' as a justification for resisting enhancement
is criticised on several grounds by transhumanists, against the
bioconservative motivation to preserve or protect 'human nature'.
For example, Nick Bostrom asserts "had Mother Nature been a real parent, she would have been in jail for child abuse and murder" thus not worthy of unqualified protection. Similarly, Arthur Caplan opposes naturalistic objections to life extension enhancements, by claiming that:
The
explanation of why ageing occurs has many of the attributes of a
stochastic or chance phenomenon. And this makes ageing unnatural and in
no way an intrinsic part of human nature. As such, there is no reason
why it is intrinsically wrong to try to reverse or cure ageing.
Congenital fear of snakes and spiders was found in six-month-old babies. Infant cry
is a manifestation of instinct. The infant cannot otherwise protect
itself for survival during its long period of maturation. The maternal instinct,
manifest particularly in response to the infant cry, has long been
respected as one of the most powerful. Its mechanism has been partly
elucidated by observations with functional MRI of the mother’s brain.
Testosterone (main male sex hormone) primes several instincts, especially sexuality; also dominance, manifest in self-affirmation, the urge to win over rivals (see competitiveness), to dominate a hierarchy (see dominance hierarchy), and to respond to violent signals in men (see aggression), with weakening of empathy. In men, a decrease in testosterone level after the birth of a child in the family was found, so that the father’s energies are more directed to nurturing, protecting and caring for the child. Unduly high levels of this hormone are often associated in a person with aggressiveness, illegal behavior, violence against others, such phenomena as banditry, etc. This is confirmed by studies conducted in prisons. The amount of testosterone in men may increase dramatically in response to any competition.
In men, the level of testosterone varies depending on whether it is
susceptible to the smell of an ovulating or non-ovulatory woman (see menstrual cycle).
Men exposed to the odors of ovulating women maintained a stable level
of testosterone, which was higher than the level of testosterone in men
exposed to non-ovulatory signals. This is due to the fact that an
ovulating woman is capable of conceiving, and therefore a man who feels the smell of an ovulating woman is given a signal to sexual activity.
Squeamishness and disgust in humans is an instinct developed during evolution to protect the body and avoid infection by various diseases.
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