By definition, 'human nature' alludes to whatever psychological characteristics are innately shared by each and every human being on this planet. Nevertheless, even living at an incidental social context, basing our opinions on personal experience and knowing nothing about behavioral biology, by favor of being humans most people feel capable of unraveling such an all-encompassing conundrum.
Just as lying under the stars does not make us astronomers and we are not geologists because of a collecting rocks hobby, experiencing human behavior does not make us an expert in our intrinsic make-up. Due to such shallow life experiences, subjective and human-biased knowledge are embraced, both potential victims of the greatest cause of misunderstandings throughout history: believing correlation implies causation. As a result of the terrible "common sense", it was mistakenly assumed that the universe revolved around us -the only way to seek a more objective truth was exhaustive theorization and experimentation. There is no reason to think it would be otherwise in regards to human nature.
Upon observing humanity's current circumstances it is presumed that such is the unmovable state of things, an error every civilization has committed. There is an exception: sometimes a revolutionary zeal emerges and the contrary extreme takes hold, assuming a blank slate without innate psychological features and then pretending to change absolutely everything via a simple formula of social engineering. The Seventies were a particularly good example of this kind of mass delusion, even in academia. However, as a general rule most people tend to delude themselves into thinking they will be the only generation in history whose culture will not change somehow. Taking into account the potential factor of environment in morphing us, it is ludicrous to ignore it completely and to resort to the easy answer: "We are naturally like this."
As a matter of fact, the whole controversy about our nature or social influence being what most affects our behavior -dubbed the "Nature vs Nurture" debate- is a utterly meaningless concept based on the assumption that such extreme points are the only two options: if our conduct is not determined by genes, it is by society. It is not so difficult to find what science has to say about human behavior, in fabulous sources such as "Genome" and "Nature via Nurture" by Matt Ridley or the course by Dr. Robert Sapolsky at Stanford University available on the Internet. Then again, reading and watching those takes weeks -that is why in this essay you will find all that information condensed in a technicality-free vocabulary.
Essentially, the rebuttal can be summarized in just one sentence: genetics usually produces behavioral propensities, not determined demeanors. Unfortunately, because of political aspirations many ignore the realities of behavioral genetics because they confuse it with a concept of servitude to the genes that justify many social ills, when the truth is that genes rarely determine behavior. Meanwhile, our dualist common knowledge has not learned from science either: it has confined itself to adopt the phrase "It's genetic" without any real understanding about what that means:
"The fault is not so much dualism — the notion of a separate mind detached from the material matter of the brain. There is a far greater fallacy that we all commit, so easily that we never even notice it. We instinctively assume that bodily biochemistry is cause whereas behaviour is effect, an assumption we have taken to a ridiculous extent in considering the impact of genes upon our lives. If genes are involved in behaviour then it is they that are the cause and they that are deemed immutable. This is a mistake made not just by genetic determinists, but by their vociferous opponents, the people who say behaviour is 'not in the genes'; the people who deplore the fatalism and predestination implied, they say, by behaviour genetics. They give too much ground to their opponents by allowing this assumption to stand, for they tacitly admit that if genes are involved at all, then they are at the top of the hierarchy. They forget that genes need to be switched on, and external events -or free-willed behaviour— can switch on genes. Far from us lying at the mercy of our omnipotent genes, it is often our genes that lie at the mercy of us." -Matt Ridley, Genome (1999)The analogy of DNA as a blueprint is missleading: gene expression in an organism may change according to the environment in spite of opposing propensities. For example, this phenomenon is observed in the fact that the overwhelming majority of women with breast cancer (93%) do not have the breast cancer gene and the same happens with most diseases and even more so with behavioral propensities such as violence: having the 'violence gene' is practically irrelevant in an environment that does not trigger said potentiality. Likewise, the testosterone hormone does not cause aggression, but it empowers it if already present. Then, should we ignore the biological field of genetics? Quite the contrary: we should be mindful of our dangerous innate predispositions and try to avoid them instead of ignoring their existence.
Due to the reciprocal relationship between natural and environmental influences, there is no conflict between nature and nurture at all but nature working via nurture. Our natural dispositions were caused by a number of environments and keep changing to this day. However, biological evolution is not the point at all: the expression of the gene considerably depends on the immediate environment of the organism, from the embryonic stage of development to old age.
The traditional view of human nature would reply that, if this is true, how is it that this society is the result? In the book "The Spirit Level: Why Equality is Better for Everyone" by Richard Wilkinson and Kate Pickett it is shown that the level of social equality directly influences the incidence of certain diseases and demeanors. The Whitehall Study showed the same effect: 18,000 civil servants were studied and it turned out that the status of their job better predicted the likelihood of a heart attack than obesity, smoking or high blood pressures. In conclusion, the incidence of certain diseases and negative behaviors largely depends on the income inequality between the poorest and the richest of a society, and between the poorest and richest societies too.
This kind of studies explains the result of living in a civilization of social inequality but not its biological cause and process. Several scientists have analyzed the relationship between certain hormones and the social status in individuals and, for example, the conclusions of the first Whitehall Study are explained by biological studies carried about with primates: the lesser is our social status the less control we have over our lives, raising the levels of a steroid hormone known as cortisol (which is expressed as stress) that among other things increases the level of blood sugar, putting us in greater danger of heart attacks and consequently upsetting the mortality rate as per the social status. Cortisol levels do not increase in response to the quantity of work done but to the implied degree of oppression and submission.
As well as the indirect genetic propensities that may exist, most human practices have a direct cause in the kind of social interaction. It is vital to understand that poverty or submission are not the problem, but inequiality itself, and that is why the higher-ups in a hierarchical tribe are afflicted as well: obsessive egocentrism and power lust are but a defense mechanism to mantain status. Even though those behaviors are part of human nature, just as violence is too, they are potentialities that can only be triggered by the environment. The aforementioned Dr. Robert Sapolsky observed with his own eyes that when the most dominant members of a baboon clan are removed -in this case because the aggressive males raided a campsite and died of tuberculosis as a result of robbed litter,- the survivor's culture ends up being much more peaceful, persisting as such even after new generations are born and baboons of other clans intrude.
Another exemplary case of the relative malleability of human nature and social influences is the study carried out by Hans Kummer in the seventies: after locating Hamadryas and savanna baboons, hierarchical and egalitarian respectively, Kummer introduced a female savanna baboon into a Hamadryas troop and did the opposite with a female Hamadryas. Unlike what may be expected considering the millions of years of genetic memory and a whole life of up-bringing that taught the females certain role, it took them only an hour to adjust their mating rituals. The moral lesson of this is not very assimilated yet it is essential for the sane workings of a modern civilization: Regardless of the exact relationship between genetic and social influences, the crucial point is that that which we call human nature is not totally immutable.
Our society is more complex than that of a baboon tribe and so is the human brain, but both a thorough analysis of our history and of modern scientific notions expose the absurdity of speaking about 'human nature' as if it was unchangeable and of social change as if it was akin to modeling clay or to filling an empty vessel. The latter is used to simplify our hopes for social changes and to hold on to outdated concepts of free will, while the former is used as an excuse to proclaim an intrinsic inability to shift to a more peaceful and egalitarian society. In the wonderful words of late astrophysicist Carl Sagan:
"Fundamental changes in society are sometimes labeled impractical or contrary to human nature, as if war were practical or as if there's only one human nature. But fundamental changes can clearly be made, we're surrounded by them. [...] The old appeals to racial, sexual and religious chauvinism and to rabid nationalist fervor are beginning not to work. A new consciousness is developing which sees the earth as a single organism and recognizes that an organism at war with itself is doomed."
(Leer la versión original: Naturaleza humana)