“What language does is to enable speakers to differ about propositions. Propositions ground inferences, which can be persuasive without being logically compelling, and on which two people can differ. Thus the invention of language, like other major transitions of evolution, generated an explosion of possibilities. When we can talk about what we want, we can also discuss, generalise, refine, extrapolate, analogise, creating fresh propositions to endorse. Wants can be grounded in basic needs and desires but, from those raw materials, talking quickly leads us to a potentially unlimited variety of new propositions about artificial things to care about: cultural conventions, institutions, art, money. These constitute the values by which we govern our lives. Each variant of human desire is ‘natural’, not in the sense of being required, but only of being made possible by nature. And it is in what nature makes possible, not in what it necessitates, that we should look for the answer to the question about what we should be or do.
“These new possibilities and the choices we make among them define who we are. And that is the core idea of existentialism as articulated by Jean-Paul Sartre in 1946 – the doctrine that for humans alone, existence precedes essence: that who we are is determined by our choices, not the other way round. Because our values have arisen in a process of debate, inference and generalisation, they are no longer even distant consequences of our basic needs. Our nature arises from choices that were not determined by our biological make-up. It is enabled, but not determined, by biology.
“That holds for us both as a species and as individuals. As individuals, we each face, at every turn, the options we are afforded that result, in part, from previous choices, both our own and those of our predecessors in the human experiment. But there is no predicting where those choices might lead as we talk ourselves into them. As a species, we are part of a lineage in which a large number of crucial transitions, brought about by chance in this one lineage but not others, have enabled new possibilities. As individuals, many of those possibilities have been spurred by the urge both to imitate and to ‘reform and innovate’. And among those, it is up to each of us to make still new choices. If there is a human nature, it is created as much as it is found.
“The unpredictable character of human nature is all the more apparent when we confront what might in retrospect look like yet one more major transition: the advent of technology, and especially the creation of the world wide web. Given that unpredictability, we cannot be sure that the existence of the web will not end up limiting our choices rather than enhancing them in some ways that we can only begin to glimpse. But even if that happens, those choices will be ones that no pre-existing conception of human nature will have dictated.
“What biology teaches us about human nature is that, in a very real sense, there is no such thing as human nature. The only coherent attitude to that fact is that of the existentialist: if there is any guidance to be found in nature, it is that there is nothing there to follow. Instead, we should aspire to create it.“
