It was originally only supposed to be a single post, and this one makes three. Now I know why Dawkins originally wrote it as a book! This should (hopefully) be my last post on the selfish gene for now; next week we’ll move on to other stuff.
Given my previous points, one might realistically wonder why people aren’t simply altruistic all the time. If altruism leads to better overall genetic survival, why are people (sometimes) selfish?
Like a lot of things, the actual result is a bit of a balancing act. While human beings share a huge portion of genetic material simply be being human, nobody’s genes are exactly the same. As such, there is still some competition between different human genomes for survival.
Especially in developed society, where the human population is large and stable, and the loss of an individual is unlikely to risk the loss of a species, people are more selfish because they can afford to be. Being selfish in that environment increases the probability that your specific genes will survive, but does not realistically decrease the probability that human genes in general will survive.
The genes themselves are not doing these probability calculations of course; it is simply the case that those genes whose expressed behaviour most closely matched the actual probabilities involved were the most likely to survive. It’s all one marvellous self-balancing system of feedback.