The myth of human nature


Heyes thinks that learning helps to explain this puzzle. Links between perception of an action and execution of the same action can be learned, so long as perception and execution are fairly reliably associated. They can come to be associated in part because individuals can sometimes look at their own actions (they can observe their own hands), in part through the use of artificial supports such as mirrors (sometimes we really can see our own faces), in part through witnessing action patterns in others when one is part of a group engaged in common tasks, and so forth.

Heyes’s view is not accepted by all, but it does have empirical backing. It helps to explain that chimpanzees can be trained to imitate, that birds seem able to imitate behaviours that they engage in collectively as flocks, that imitation in newborn human infants – except with respect to tongue protrusion – takes time to emerge, and so forth. Imitation is just the sort of trait that one would presumably want to count as natural, and yet its adaptive development appears to rely essentially on cultural influence.

So human nature is a confused concept, because it blurs a number of distinctions we should try to keep in sharp focus, such as the distinction between traits that are important for our species’ distinctive evolutionary trajectory, traits that are ubiquitous in our species, and traits that are “hardwired” into our brains. Is there any evidence, though, that the notion of human nature can do any harm?

Many of us find it hard not to think in terms of human nature and the natures of other species. Psychological research done by a variety of scientists including Scott Atran and Susan Gelman suggests that this tendency emerges early in the lives of young children. Four-year-olds tend to think that each species has an internal “essence” which drives the development of that species’ typical features. So children think that all dogs possess a “doggy” essence, which results in standard “doggy” behaviours and appearances – waggy tails, barking, energetic running about and the like. They also believe these essences can misfire: this might result in an individual dog which refuses to wag its tail. Of course, modern biology denies that these essences are real, so the research reveals a widely shared error in our intuitive ways of thinking about animals and plants.

This approach to the nature of species begins to look more sinister in the light of Gelman’s more recent research, which indicates that we do not only think of biological species as having hidden essences. We also tend to think, erroneously, of course, that races have internal essences. Although Darwin claimed to see variation everywhere, he was as prone as the next Victorian to sweeping generalisations about the nature of “the negro” or “the Australian”, and he endorsed his contemporary William Greg’s description of “the careless, squalid, unaspiring Irishman”. This kind of essentialist thinking is hard to correct with observational evidence. If internal essences can regularly “misfire”, then it will be hard to persuade someone that there is no essential “doggy” nature merely by pointing to individual dogs that abhor chasing after sticks. And it will also be hard to persuade someone of the error of thinking there is an underlying Irish essence, merely by demonstrating how many individual Irishmen are full of application and ambition. It is here that talk of what we owe to our “natures” becomes not just misleading but harmful. These supposed “essential natures” arguably underlie damaging and persistent racist and sexist stereotypes.

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Appeals to what is natural, as well as appeals to the nature of the human species, sometimes appear in conservative arguments against the use of new reproductive technologies. Michael Sandel, a highly respected philosopher, has appealed to what is “natural” in his case against so-called “enhancement” technologies. These are technologies of different kinds – they might involve drugs, prostheses or genetic alteration – that promise to augment human abilities beyond the norm required for good health. Questions of the morality of enhancement are once again in the newspapers these days, because of the proposition that new “genome editing” technologies such as the CRISPR-Cas9 technique might someday be used not only for controlling inherited diseases but potentially for introducing genes with additional non-therapeutic benefits into the human germline. In an article in Nature earlier this year, a group of scientists working on these techniques cautioned that “Many oppose germline modification on the grounds that permitting even unambiguously therapeutic interventions could start us down a path towards non-therapeutic genetic enhancement. We share these concerns.”

Sandel’s case against enhancement draws on the idea that we need to think of children as “gifts”. Parenthood, he says, teaches the importance of “openness to the unbidden”, and it restrains “the impulse to mastery and control”. That is why, says Sandel, we shouldn’t intervene in what nature presents us with when we conceive and raise children. The problem with this way of opposing enhancement is that it seems to have the result that in addition to rejecting the prospect of “designer” babies, augmented beyond the healthy norm with genome editing techniques, we should also refuse to correct congenital diseases. Doesn’t this, too, represent an effort to “master” what nature has given us? Sandel rejects that interpretation of his argument. He argues that “To appreciate children as gifts or blessings is not to be passive in the face of an illness or disease. Healing a sick or injured child does not override their natural capacities but permits them to flourish.”

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This sounds reasonable, until we ask ourselves how we are supposed to tell the difference between capacities that are “natural” to humans, and capacities that are instead the result of over-ambitious distortions of those natural capacities. Consider someone born with the disease phenylketonuria (PKU). Left untreated, this disease leads to severe learning and behavioural difficulties. Fortunately, its detrimental effects can be eased significantly if the growing child is given a special diet, low in the commonly-occurring amino acid phenylalanine, from birth onwards. Have we overridden the child’s natural capacities by giving her a special diet? Presumably Sandel wants to count this as allowing her natural capacities to flourish. But then it becomes hard to see what one might understand by a person’s “natural capacities”, unless we simply mean to pick out all the capacities that person might possibly attain, if only they had access to suitable medical, technical and cultural interventions.

We have now opened ourselves up to the thought that an individual’s “natural capacities” include the enhanced capacities she might attain if only she had access to genome editing. In desperation one might say that genome editing is not itself a “natural” process, hence one cannot describe it as allowing a person’s natural capacities to flourish. Genome editing is, after all, a considerable technical achievement. But it is equally implausible to think that the provision of an artificial diet, low in phenylalanine, is “natural” in that sense. Appeals to what is natural or unnatural are of no use if we want to build a case against genome editing. Nature cannot do the ethical work intended for it.