Genes surely define the behavioural envelope within which an individual can operate. This envelope, though, is quite wide. Nevertheless, one would think that after some 10,000 generations of evolution as anatomically modern humans, living in societies where cooperation is primal, that all those beneficial behavioural traits which had a genetic component, would have by now been selected. But psychopaths are not extinct, anti-social behaviour is very common and compassion is not a survival trait to be selected for. Barbarism has not been deselected by evolution. It could be that the same genes which give religious fanaticism also give rise to artistic creativity.
One would also have expected that the intelligence we credit humans with, and see as a key differentiating factor from other creatures, would also have been selected as a trait. Of course intelligence is not so easily defined and it certainly is not just the result of an IQ test. There are suggestions, from brain size measurements, that intelligence, as given by brain size, peaked when we were still hunter gatherers, possibly because that was when individuals needed to be very autonomous and – by inference – quite selfish to survive. IQ tests today are not a good predictor of the success of an individual in society, probably because the test does not capture those aspects of intelligence that have to do with leadership, team work or entrepreneurial ability.
There was a time when light and dark were outside human control. So far we have left evolution to take its slow, natural, wasteful, trial and error course. But the speed of natural selection is now completely out of sync with the speed of change. The few attempts to guide evolution have been discredited by the manner in which they have been applied. They have been based on the principles we have used to breed livestock and dogs by terminating unwanted characteristics and only allowing individuals with desired characteristics to have progeny. The Nazi experiments with eugenics and even Margaret Sanger’s objectives of controlling the black population in the US (by making abortions freely available) were horrible (still are in some instances), in their manner of execution. But the idea of guiding our own evolution is still sound and an idea whose time has still to come. We are already tinkering with eugenics – though in a very amateurish way – when foetuses are aborted, or IVF is used, or when sperm banks are drawn upon, or fertility drugs or surrogacy are employed. Now, we have a sort of eugenics by default. When foetuses are screened genetically as a matter of course, and when genetic manipulation and correction becomes possible then eugenics will have properly arrived.