History

The concept of nature as a standard by which to make judgments was a basic presupposition in Greek philosophy. Specifically, "almost all" classical philosophers accepted that a good human life is a life in accordance with nature.

On this subject, the approach of Socrates, sometimes considered to be a teleological approach, came to be dominant by late classical and medieval times. This approach understands human nature in terms of final and formal causes. Such understandings of human nature see this nature as an "idea," or "form" of a human. By this account, human nature really causes humans to become what they become, and so it exists somehow independently of individual humans. This in turn has sometimes been understood as also showing a special connection between human nature and divinity.

The existence of this invariable human nature is, however, a subject of much historical debate, continuing into modern times. Against this idea 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, the latter of whom stated:“ We do not know what our nature permits us to be. – Jean-Jacques Rousseau, Emile ”


Since the mid-19th century, thinkers such as Hegel, Marx, Kierkegaard, Nietzsche, Sartre, structuralists and postmodernists have also sometimes argued against a fixed or innate human nature.

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 all modern science they seek to explain without recourse to metaphysical causation.) They can be offered to explain its origins and underlying mechanisms, or to demonstrate capacities for change and diversity which would arguably violate the concept of a fixed human nature.

Socratic philosophy

Philosophy in classical Greece is the ultimate origin of the western conception of the nature of a thing. The philosophical study of human nature itself originated, according to Aristotle at least, with Socrates, who turned philosophy from study of the heavens to study of the human things. Socrates is said to have studied the question of how a person should best live, but he left no written works. It is clear from the works of his students Plato and Xenophon, and also what was said by Aristotle (Plato's student) about him, 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 divided nature, divided in a specifically human way. One part is specifically human and rational, and divided into a part which is rational on its own, and 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 or epithumiai. 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, 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, meaning an animal which is born to couple when an adult, thus building a household (oikos) and in more successful cases, a clan or small village still run upon patriarchal lines.
Man is a political animal, meaning an animal with an innate propensity to develop more complex communities the size of a city or town, with a division of labor and law-making. 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). He says "we enjoy looking at accurate likenesses of things which are themselves painful to see, obscene beasts, for instance, and corpses." And 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, but the particular teleological idea that humans are "meant" or intended to be something, has become much less popular in modern times.

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. Human nature is an example of a formal cause according to Aristotle. Their teleological concept of nature is associated with humans having a divine component in their psyches, which is most properly exercised in the lifestyle of the philosopher, which is thereby also the happiest and least painful life.

Modernism

One of the defining changes occurring at the end of the Middle Ages, is 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 was rejected as useless speculation. Also, the term "law of nature" now applies any regular and predictable pattern in nature, not literally a law made by a divine law-maker, and in the same way "human nature" becomes 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, and then 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 is 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. (A proposal which was also made, less famously, 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 and 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 Francis Bacon and Thomas Hobbes, of avoiding consideration of metaphysical explanations for any type of cause and effect. He was accused of being an atheist. Concerning human nature also, he wrote for example:
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 changes, branching into different disciplines and approaches, and the study of human nature changes 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.

Psychology and biology

A long standing question in philosophy and science is whether there exists an invariant human nature. For those who believe there is a human nature, further questions include:

• What determines/constrains human nature?
• To what extent is human nature malleable?
• How does it vary between people and populations?

Since human behavior is so diverse, it can be difficult to find absolutely invariant human behaviors that are of interest to philosophers. A lesser (but still scientifically valid) standard for evidence pertaining to "human nature" is used by scientists who study behavior. Biologists look for evidence of genetic predisposition to behavioral patterns. Human behavior can be influenced by the environment, so penetrance of genetically predisposed behavioral traits is not expected to reach 100%. A type of human behavior for which there is a strong genetic predisposition can be considered to be part of human nature. In other words, human nature is not seen as something that forces individuals to behave in a certain way, but as something that makes individuals more inclined to act in a certain way than in another.

Evolutionary psychology (EP) posits that the mind is made up of a massive number of interacting emotional, motivational and cognitive adaptations or "mental modules." EP seeks to identify which human psychological traits are evolved adaptations - that is, the functional products of natural selection or sexual selection. Adaptationist thinking about physiological mechanisms, such as the heart, lungs, and immune system, is common in evolutionary biology. Evolutionary psychology applies the same thinking to psychology, arguing that the mind has a modular structure similar to that of the body, with different modular adaptations serving different functions. Evolutionary psychologists argue that much of human behavior is the output of psychological adaptations that evolved to solve recurrent problems in human ancestral environments. This view has been critiqued as essentialist by some, and as neglecting "natural" genetic, environmental and individual variation (and that the closest you can come is norms of reaction), and as equivocating between the levels of genes, developmental programs, and actual human psychology/culture, and between individuals and population averages.

Arguments for invariance

All individuals and all societies have a similar facial grammar. Everyone smiles the same, and the way we use our eyes to convey cognition or flirtatiousness is the same. Heterosexual females find male faces that are rated more masculine and aggressive, less feminine and sensitive, more attractive during ovulation, the stage of their menstrual cycle when women are most fertile.

No success has ever been scientifically demonstrated in re-assigning an individual's handedness. Although individuals may change their external behavior (picking up scissors with their right hand instead of the left, for instance), their internal inclination never changes. Even people who lose a limb, who physically do not possess the ability to pick up scissors with their left hand, will try to do so if they are "left-handed." The percentage of left-handers in all cultures at all times remains constant (because left-handedness is a recessive trait.[citation needed])

Newborn babies, far too young to have been acculturated to do so, have measurable behaviors such as being more attracted to human faces than other shapes and having a preference for their mother's voice over any other voice.

In his book Human Universals, Donald E. Brown presents his case and identifies approximately 400 specific behaviors that are essentially invariant among all humans.

Arguments for social malleability

The Duke of Wellington is said to have become indignant upon hearing someone refer to habit as "second nature." He replied, "It is ten times nature!" William James likewise referred to habit as the flywheel of society. Habits, though, are by definition acquired, and different habits will be both the effect and the cause of very different societies.

In An Essay Concerning Human Understanding, John Locke posits that the human mind is at birth a tabula rasa or blank slate, and that the individual has freedom to shape their nature. Nayef Al-Rodhan argues that such freedom is restricted by inbuilt predilections and moral sensitivities.

Different human societies have held very different moral codes. Thus, regardless of whether objective morality exists or not, humans are clearly capable of imposing a wide variety of different moral codes on themselves.

Some have argued that the role for nurture comes not from the absence of impulses in human nature but from the plethora of such impulses—so many, and so contradictory, that nurture must sort them out and put them into a hierarchy.

Some believe there is no single universal law of behavior that holds true for all human beings. There are many such laws that apply to the majority of individuals (for example, the majority of individuals try to avoid dying), but there are always exceptions (some individuals commit suicide). Most animals, including humans, have an innate self-preservation instinct (fear of injury and death). The fact that humans may override this basic instinct is seen as evidence that human nature is subordinate to the human mind, and/or various outside factors. However, this may not be entirely unique to the human mind, as certain animals are observed to willfully commit suicide.

Nature & Animals