I am not an evolutionary biologist so please excuse and correct any mistakes if you can. Lets assume there are some physical differences between the castes. These differences would have been brought into existence because at some point the respective populations were isolated and living under different sets of evolutionary pressures. If, over time, you remove physical isolation but replace it with cultural taboos against inter-breeding then the effect of these ancestral pressures can be preserved. Does that make sense?
It seems to me the real issue here is our inability to reckon with the fact that IQ is just another adaptation. If we were talking about a less central trait, say hair color, the down votes, insults and the flagging of the post would seem ridiculous, even though the exact same reasoning would apply,
It seems to me the real issue here is our inability to reckon with the fact that IQ is just another adaptation. If we were talking about a less central trait, say hair color, the down votes, insults and the flagging of the post would seem ridiculous, even though the exact same reasoning would apply,