It's not a new worry, that by interfering with the course of nature we are somehow abusing or aborting the natural course of evolution. It can be traced as far back as the Renaissance, and probably further. It may be the case that we are allowing otherwise unviable people to reproduce through supporting them, but then surely that is more than compensated for by the fact that we are increasingly able to remedy any lack of viability, in them or their children, in a variety of ways, including gene manipulation. But it just isn't true that Darwinian evolution has been somehow turned aside in a more general sense. Study after study shows that taller people are more successful in life, including mating, then shorter people. More than ever, there is a received idea of what constitutes beauty, and how would this not result in a gradual trend towards children who are closer to that ideal?
Resistance to disease has also not gone away as a factor in selection. It is reported that some individuals are resistant to HIV infection, or that, if infected they do not develop AIDS. This is a classic example of selection at work; those with the genetic factors that predispose towards resistance will survive and breed; others have fewer chances in that direction. This type of selection would appear to be operating in richer societies as well as in poorer ones, although it may be partly negated when individuals are rich enough – or society is rich enough – to pay for drugs which retard or cure HIV or AIDS.
It may be supposed that, towards the middle of the century, as improved medical techniques increasingly offer life chances to everyone regardless of genetic and environmental factors, Darwinian evolution will become less of a factor in pure 'survival of the fittest' terms. There is unlikely to be any cultural resistance to this trend. The impact of genetic manipulation will be discussed below.
The future for Darwinian evolution of human cognitive faculties is a tougher nut to crack. There certainly is a premium on cognitive ability in the modern world, as there has been for thousands of years if not much longer, and on the conforming, cooperative and communicative behaviours that are required for group success. And no-one could pretend for a moment that the modern world is anything but more complex and more demanding cognitively than it used to be. The cult of individuality might be thought to work in the opposite direction, but that is a superficial view. At almost all points, the individual interacts with the modern world through the agency of groups: at school, in the office, in the army, in sport, in the pub. Even a person working in an intensely individual way, say, a top golfer, cannot succeed without her groupish 'support team', the approbation of her peers, and her fan club. And as pointed out in previous chapters, globalization and the Internet will increase, not reduce the opportunities for people to form like-minded groups.
All of this social complexity could be expected to work for greater cognitive social skills, although its impact on marriage and reproductive chances may be lessened by programmes aimed at reducing social disparities.
Bionic and genetic techniques to improve (artificially – whatever that means) cognitive performance may also tend to reduce the role of 'natural' Darwinian selection, although in terms of genetic results it may be hard to tell the difference between an improvement in neuronal memory functioning brought about by genetic manipulation and one brought about by failure to breed on the part of people whose memory skills are too poor to allow them to perform successfully in the world. And if this book is right in supposing that technology will permit a great expansion of human inter-connectedness through the creation of shared or collective cognitive spaces (see Chapter 12), then that will force a rapid evolution of the necessary cognitive skills in which Darwinian and 'artificial' influences may be hard to disentangle.
As a generalization, it is probably true to say that Darwinian evolution in the strict sense will have a decreasing impact on human mutability during the second half of the century; but it is not clear that this is a very useful conclusion. What is certain is that the human cognitive apparatus, along with our physical nature, is going to change as never before.
One caveat that must be entered relates to the possible interplay of Lamarckian genetic adaptation with the dramatic changes in the human phenotype that may result from bionic and genetic techniques (see below), but given the present state of scientific knowledge about genetic processes, it is impossible to reach clear conclusions in that direction.