[pron]

Natural selection is not about the phenotype. It is not beneficial to the mother to have "her genes" propagate. Natural selection works on a gene-by-gene basis and, if anything, the genes "use" the individual as a carrier serving their "benefit", not the other way around. Even more precisely, it's about genes becoming more or less widespread in the population. A gene doesn't "care" what happens to one of its carriers. You gain nothing by spreading "your" genes; your genes, however, may use you as a vehicle to spread themselves.

The question is, then, if there is some gene that encourages adoption, will such a gene spread in the population or not? I'm not sure I see why it would. However, if such a trait is already spread in the population, especially if it's not a specific gene but an outcome of others, indeed I don't think there would be selective pressure working against it for the reason you mentioned.

[dTal]

>You gain nothing by spreading "your" genes; your genes, however, may use you as a vehicle to spread themselves.

Getting philosophical here, but what does it even mean for me to "gain something", given that my entire existence is a conglomeration of mostly-cooperating genes trying to spread themselves, and my values, desires, and outlook on life are heavily controlled by said genes? Spreading my genes is the intrinsic value, from which all my other instrumental values like eating tasty food, making good friends, enjoying sex etc are derived.

[pron]

> Spreading my genes is the intrinsic value

That's not the way natural selection works. A gene either spreads in the population or not, and individuals are merely carriers of a particular gene. It is no more "your" gene than it is "your" flu virus that you spread when infected. The gene and the virus "use" you; you don't use them.

Of course, because genes, like a flu virus, use us as carriers, they can only spread if we help them spread, so if we come to think of genes that we and others carry as "our" genes then that helps those gene spread. But natural selection doesn't care about gene carriers beyond their role as carriers any more than a flu virus does.

[dTal]

We seem to be agreeing, but I don't think you really engaged with my point with this reply. What is "me"? There is no "I", that exists independently of the genes that "I" carry, that can be "benefited" at the expense of those genes. My genes do not use me. I do not use my genes. I am my genes. It is fundamentally impossible for me to act in a way that is not calculated to spread the genes that constitute me. Any behavior that I perform is the result of inclinations which have been programmed into me for the express purpose of successful reproduction. No other selection pressure exists.

(To avoid an argument: the picture is murkier when one considers that we are also meme carriers, which also affects our behavior, and that memetic and genetic reproduction are not entirely aligned; nevertheless, we have no more control over our memes than over our genes, so the core point remains: there is no "me").

[pron]

> There is no "I", that exists independently of the genes that "I" carry, that can be "benefited" at the expense of those genes

I disagree, because even if you were indeed merely the sum of your genes, natural selection works on a gene-by-gene basis, not on a full genotype basis. Furthermore, each of "your" genes -- unlike your genotype -- is not unique to you (that's the whole point of genes spreading; a successful gene is one that is carried by many individuals). Unless you clone yourself, spreading your genotype is simply not an option available to you whether you see value in that or not.

In other words, even if you believe you are no more than the sum of the words that constitute the sentence that is your genotype, natural selection does not work to spread that sentence but its constituent words. In fact, it works to spread only some of those words and against the spread of others. In a way, the genes you carry are in competition with each other.

> It is fundamentally impossible for me to act in a way that is not calculated to spread the genes that constitute me. Any behavior that I perform is the result of inclinations which have been programmed into me for the express purpose of successful reproduction. No other selection pressure exists.

That takes things way too far. We are not "programmed" by our genes, as seen in identical twins. But to whatever limited extent genes do "program" us, their spread is not necessarily dependent on you reproducing. That's the whole discovery of kin selection: because your genes are shared with others, behaviour that sacrifices you for the sake of someone else will also spread your shared genes in the population -- just not through you.