I was worried recently when I read the phrase “goal-directed evolution” in some philosophy writing. This annoys me since it shows what I consider to be a fundamental misunderstanding of what evolution is and does, and philosophers should know better.
People often think, incorrectly, that genes, or chromosomes, or animals, or evolution as a whole are invested with purpose, with agency. This is patently false. There is no agency in the chemical make-up of genetic material and evolution, as a theory and mechanism, has no agency.
In other words, a gene won’t make you do something in order to achieve a certain goal. Genes have associated behaviour traits, but they do not exist in order to achieve a particular end. You see, the crux of what I am trying to say is that they exist. Anything which exists must have characteristics which are not detrimental to its existence, otherwise it will not exist. If all trees suddenly self-combusted, as a characteristic, after 8 months, then trees, as we know them, would probably not exist.
A gene doesn’t develop or mutate in order to increase its chances of remaining existent. These things have no agency. Simply put, they are bits of stuff. And if these bits of stuff mutate in a bunch of different ways, then the ways which improve its chance of continuing to exist will cause their bits of stuff to continue, and the stuff which mutates detrimental characteristics to existence will cease to exist. The notion of the selfish gene is prevalent here, but even that (as is recognised) is a description which can invoke ideas of agency.
Steven Pinker, in How The Mind works, touches on this idea, but then uses ambiguous language to discuss this ‘selfishness’ (p. 399):
DNA, of course, has no feelings; “selfish” means “acting in ways that make one’s own replication more likely.” The way for a gene to do that in an animal with a brain is to wire the brain so that the animal’s pleasures and pains cause it to act in ways that lead to more copies of the gene.
A gene doesn’t wire a brain SO THAT something happens. It wires a brain randomly in that particular way and it happens to be a way which increases that organism’s chances of survival or reproduction. Thus the wiring of the brain as a result of that gene is a mechanism that will continue to exist through the existence of the host organism. The gene, unwittingly (since it has no wits) has mutated into something advantageous to the host, thus ensuring its continued existence. However, it did not do that SO THAT the organism, or even itself, survives. It does that AND it survives, and continues to survive.
These genes get ‘selected in’ by evolution through natural selection, but there is no agency involved. Evolution or an organism or a gene doesn’t say, “Hey that mutation I have just undergone is very beneficial to my continued existence!”
It is a blind process underwritten by the philosophy of existence. Either things exist, or they don’t. The things that continue to exist have properties conducive to existence. Things that don’t exist, don’t (or didn’t, or… you get the picture).
Theists (and many non-theists too) don’t seem to get the sheer necessity of this philosophy; the sheer necessity of this mechanism to existence.