As it happens, not long ago I was yet again in a conversation about diary products, lactose intolerance, and evolution. It is very popular these days to repeat the mantra “cow’s milk is for cows, not for humans”. More and more people are buying into these “veganistic” idea that we were never meant to drink milk, but we “forced ourselves into evolving in drinking it, but it hasn’t worked very well, and that’s why it’s harmful for us”.
When I hear stuff like that, I shake my head, and think “would they believe they if they started ingesting mercury, they would eventually evolve to be able to live off mercury rather than just dying for its poisonous characteristics”?
That said, one colleague made the acute objection that the cows we drink the milk of are those we selectively bred for the very reason they produced milk we could drink. Of course, he also made the blind-faith leap that “this is how evolution works” (no, it isn’t — in fact, human aided selective breading only goes to show that evolution could never work unaidedly; plus, selective adaptation manipulates existing information, but never adds new information).