If evolution grinds to a halt, we move on

According to professor Steve Jones human evolution is grinding to a halt. The reason is, at least in the developed world, we have so good living standards and hence low mortality that we are not suffering any selection. He also argues that the mutation rate has been reduced because changes in reproduction and the larger gene pool. He concludes: "So, if you are worried about what utopia is going to be like, don't; at least in the developed world, and at least for the time being, you are living in it now." As I see it, he has a very modest view of utopia. More seriously, do we have some kind of obligation to evolve?

The biggest problem with the claim is of course that it is likely factually not true. As a lunch hour lecture at UCL about evolution it might have been entertaining or illuminating enough to outweigh this boring fact, but when spread around in the news the claim becomes problematic.

Modern medicine has reduced infant and child mortality enormously, removing some selective pressures. But there is still a significant selective pressure occuring, much of it occuring long before birth. Only about 50% of embryos successfully implant in the utreus, and over the first few months over 60% of all conceived embryos die. Many of these spontaneous abortions are likely due to selective processes. And while most children born will survive to become fertile adults, the number of children they will have is affected by factors such as religion, education, economy and individual choice - plenty of new selective pressures. If religious people have more kids than non-religious people and there is a genetic factor predisposing for religiosity, we will see more of it in future generations. In addition, as noted by PZ Myers, by reducing selection we get more genetic variation - in itself an evolutionary change. There are also problems with the claim that younger fathers generate fewer mutations, since there is more than enough mutations to go around anyway, and it is pretty clear that there is unfortunately plenty of selective pressure in sub-Saharan Africa. Some other criticisms of Jones ideas can be found here and here.

But leaving the facts aside, suppose we actually had a good reason to think we had successfully removed all major evolutionary pressures. Would it matter?

Evolution is about changing frequencies of genes. Nobody truly cares about that. What we care about is the consequences of these particular genes - illness and health, strong and weak sides, crucial human traits and cosmetic differences. Even these traits would change from individual to individual due to the randomness of genetics, so we would not just become uniform. In order for the lack of evolution to matter to us it would have to do something we find valuable to our traits. However, evolution is not intended for human goals or values. Contraceptives give us control over our reproduction, something that individually and collectively helps us flourish, yet from an evolutionary perspective limiting reproduction is almost always "wrong". Similarly evolved behaviours such as xenophobia or a sweet tooth give us problems, but are selected for. Ageing appears to be a by-product of evolution, just because there is no selection for post-reproduction lifespan.

Only in areas where evolution and human desires are congruent would a lack of evolution be bad. We are slowly increasing our mutational load since people with myopia, asthma, genetic disorders and vulnerability for treatable illnesses are not selected away. But the value of human lives is much greater than the health benefits from having vulnerable people die: we choose compassion over evolution any day. And thanks to our technology, we can also find non-evolutionary solutions to the problems.

Maybe there is some form of duty to evolve? This idea seems to crop up in various forms in popular culture, usually linked to the ideas that (1) there is some "next stage of evolution" waiting to succeed humanity and (2) this stage is better. This is often combined with loose ideas that (3) the species has a value beyond its members. The problem with 1 is that it is just wrong: evolutionary processes as they naturally happen are random, and whatever successor species appears will depend on random chance and environmental conditions. There are no big-headed supermen waiting in the wings. There is also a crucial difference, as discussed above, between the "better" evolution favours (having many grandchildren) and the "better" humans favour (moral dignity, beauty, intelligence - the list is endless and individual). 3 has a very bad track record. Arguing that the collective - or rather, the abstraction of the collective - has priority over its members has led to many of history's worst atrocities.

There does not seem to be any link between human rights and being the same biological species. People who think human rights are the results of a social contract clearly do not need to assume any species similarity. Natural law concepts of human rights also have little need for species: If we discovered that the inhabitants of Elbonia could not interbreed with other humans, it would not change our opinion about their moral status - they would be autonomous moral agents, ends in themselves, with the same needs and desires as the rest of us. If aliens or intelligent monkeys appeared there would be no problem in accommodating them into a framework of sentient rights. Only if the newcomers were fundamentally different, for example completely lacking individuality, might we need to question the applicability (it is worth noting that we are quite ready to give human rights to humans with vastly different minds, be they geniuses, autists or sociopaths).

So there is no reason to argue that we must keep together as the same species, nor that we have a duty to change our species "for the good of the species". There might still be good reasons to change ourselves: we might want to select against genetic illnesses and we might desire genetic enhancements that slow ageing or increase creativity. But these are for the good of existing people or their children. We should strive to become better people, but that is because it is good to be a better person.

There is little reason to bring about such changes the natural way - it is the outcome that is good, the means do not matter. Evolution is an exceedingly slow and inefficient process for the things that it can do, and there are many things it cannot do. Bringing about genetic changes of course carries a moral responsibility. This might be a reason some like evolution: nobody is responsible for those killed by it. But we can and ought to do better.