I completely agree with you. I don't believe that every action is correctly designed to optimize gene transmissions and I think you put it into very eloquent words with: "it is trying to say that we are at a global maximum in a space that is probably more nonlinear."
However, I think that there are certain actions that we take that are clearly defined by our genetics, like the fact that we eat, or that we have sex. And having affairs is one of those.
That we have sex is defined by our genes; who we have sex with is a choice we make by thinking about it, not something pre-encoded by our genes, as you are trying to say.
Which actually makes sense given your premises. A good evolutionary "strategy" would be to evolve brains that can make choices far more complex (literally, inelligently) than what can be pre-encoded by genes that change slowly and mutate randomly.
In summary, you are implying that when you have an affair, it's not a choice, but it's determined by your genes. Thus, it's not a moral issue; you have no choice. Thus, you can justify having any particular affair by claiming "genes," and you should just forgive any particular affair your wife has for the same reason. And I'm saying, no, it's a choice.
A cursory glance at discussions online regarding relatinoships and attraction would show that most people would say they don't decide who to be attracted to, that it simply is what it is.
Just because we can show that cheating has evolutionary benefits and thus people are likely prediposed to cheat in certain situations does not eliminate any moral considerations. Morality is precisely the idea of overriding any base instincts with what we "know" to be proper behavior. Claiming your genes made you do it is no more a loophole for morality now than "the devil made me do it" was before the discovery of DNA.
There was actually a study that showed female rats are more attracted to (read: had sex with) male rats with very different immune systems. The way she senses this is by the pheromone (smell) he gives off and as a consequence, her offspring have stronger immune systems.
In other words, this study suggests at least to some degree we don't even choose who we have sex with. Haha.
The purpose of my comment was to point out that humans have a (sophisticated) brain, something critical that you had overlooked, and you still seem to have missed that.
You argued that "who we have sex with is a choice we make by thinking about it, not something pre-encoded by our genes." I was trying to suggest maybe the opposite is true to some extent by sharing that study regarding the rats with you. Female rats unconsciously have sex with male rats whose pheromones smell like their immune systems are very different, in other words, who they select as mates is something pre-encoded in their genes.
Are you arguing that because we have brains we can 'override' what our genes would otherwise have us do?
there's a lot of stuff that people do that has nothing to do with thinking, and i'd argue that the idea of "intelligent choice" explains pretty much nothing in the context of mating/pairing. example: why are some people of the opposite sex "your type" and some not?
I agree absolutely it is more likely. And I read The Selfish Gene. But how could you disprove that theory? it is sort of too obviously true, if you see what I mean. Which is why I brought up the homosexuality counterexample. So I don't think it should be taken as undeniable, even though it is plausible.
I see what you're trying to get at. You're saying that "x% of children are not genetically related to their fathers because women have affairs to increase the competition for her egg" is a theory, not to be taken as something true.
I didn't mean to make myself sound like that I was saying it was. I was just suggesting something and I agree with you: it is plausible, but it is still a theory at the end of the day.
I rarely read discussions between 2 people beyond the 3rd or 4th reply, but this one kept me wanting to see how this goes, very well concluded. This is the reason I love HN, quality of discussion is much better than any other place.
However, I think that there are certain actions that we take that are clearly defined by our genetics, like the fact that we eat, or that we have sex. And having affairs is one of those.