Touche. It is possible to explain almost anything ex post. Moreover, it’s really unclear (and what I’ve read does not address) how a gene that causes someone to not reproduce gets passed on. Assuming that just you have the gene and your relatives don’t, it’s beneficial. But if you all have the gene, that’s a very different story. A gene that causes me to sacrifice myself to save my brothers is conditional—it doesn’t matter unless the need arises. A gene that causes me to prefer non-procreative sex doesn’t seem conditional in the same way—it simply prevents me and anyone who has it from reproducing.
In short, while one can rationalize the behaviour as advantageous ex post, it’s rather hard to actually put that together cogently, and it’s a very long way from getting rid of, “largely accidental” as an alternative explanation.
I will admit bias on this issue, having dated a woman with a lesbian identical twin.
Homosexuality could be controlled by environmental factors and appear at a good rate for kin selection while being genetically present in more people.
Here’s a more straightforward fictional example: In Elcenia, there’s a type of natural magic-user called “lights”. They have healing magic—really heavy-duty healing magic, equal to or better than modern Earthly care in most respects and infinitely cheaper. However, lights can’t heal themselves or each other, so it’s not such a great thing to be a light—you’re much more likely than the people around you to die of disease or injury. But it’s really, really useful to have a close family member who’s a light, because they’ll heal you when you get sick or hurt. So what happens in practice is most people in species where lights appear have the necessary genetic component, but only about 1-2% of the population depending on region encounter enough ambient magic in the womb to turn into actual lights.
I get the underlying theory just fine. It’s a neat fictional example, but (and I’m not familiar with the underlying fiction) it would probably be extremely fitness-enhancing. A male light would probably be incredibly high status and have little difficulty producing offspring. If it were purely genetically determined, it seems like it’d be pretty hard to sustain—no one would want it for their own children. If it were recessive, it might work out better, but there still seems a substantial problem of free-loading.
Thus, this evolutionary explanation for homosexuality partly undermines itself: it’s genetic, but it’s not quite genetic and there’s other stuff going on that determines whether or not it gets activated. So it’s either genetics (actively-selected) + environmental factors or genetics (random noise) + environmental factors. That’s not a very clear case for kin selection, to say the least.
My claim isn’t that it couldn’t possibly be related to kin selection. It’s that, like many ev-psych claims, the evidence for “or something else is going on” is far too strong to make a definitive claim, particularly because the outcome is the exact opposite of what you’d expect from simpler evolutionary theory. Otherwise, you risk combining two theories in a way that can explain far too many outcomes. Any individual who fails to reproduce can divert resources to his siblings. You could just as easily say many negative traits that don’t show up with absolute consistency are also advantageous. This seems like a stretch.
In retrospect I will admit that this example detracted from my overall point and was poorly chosen.
Touche. It is possible to explain almost anything ex post. Moreover, it’s really unclear (and what I’ve read does not address) how a gene that causes someone to not reproduce gets passed on. Assuming that just you have the gene and your relatives don’t, it’s beneficial. But if you all have the gene, that’s a very different story. A gene that causes me to sacrifice myself to save my brothers is conditional—it doesn’t matter unless the need arises. A gene that causes me to prefer non-procreative sex doesn’t seem conditional in the same way—it simply prevents me and anyone who has it from reproducing.
In short, while one can rationalize the behaviour as advantageous ex post, it’s rather hard to actually put that together cogently, and it’s a very long way from getting rid of, “largely accidental” as an alternative explanation.
I will admit bias on this issue, having dated a woman with a lesbian identical twin.
Homosexuality could be controlled by environmental factors and appear at a good rate for kin selection while being genetically present in more people.
Here’s a more straightforward fictional example: In Elcenia, there’s a type of natural magic-user called “lights”. They have healing magic—really heavy-duty healing magic, equal to or better than modern Earthly care in most respects and infinitely cheaper. However, lights can’t heal themselves or each other, so it’s not such a great thing to be a light—you’re much more likely than the people around you to die of disease or injury. But it’s really, really useful to have a close family member who’s a light, because they’ll heal you when you get sick or hurt. So what happens in practice is most people in species where lights appear have the necessary genetic component, but only about 1-2% of the population depending on region encounter enough ambient magic in the womb to turn into actual lights.
I get the underlying theory just fine. It’s a neat fictional example, but (and I’m not familiar with the underlying fiction) it would probably be extremely fitness-enhancing. A male light would probably be incredibly high status and have little difficulty producing offspring. If it were purely genetically determined, it seems like it’d be pretty hard to sustain—no one would want it for their own children. If it were recessive, it might work out better, but there still seems a substantial problem of free-loading.
Thus, this evolutionary explanation for homosexuality partly undermines itself: it’s genetic, but it’s not quite genetic and there’s other stuff going on that determines whether or not it gets activated. So it’s either genetics (actively-selected) + environmental factors or genetics (random noise) + environmental factors. That’s not a very clear case for kin selection, to say the least.
My claim isn’t that it couldn’t possibly be related to kin selection. It’s that, like many ev-psych claims, the evidence for “or something else is going on” is far too strong to make a definitive claim, particularly because the outcome is the exact opposite of what you’d expect from simpler evolutionary theory. Otherwise, you risk combining two theories in a way that can explain far too many outcomes. Any individual who fails to reproduce can divert resources to his siblings. You could just as easily say many negative traits that don’t show up with absolute consistency are also advantageous. This seems like a stretch.
In retrospect I will admit that this example detracted from my overall point and was poorly chosen.
That… has a lot of potential.