Comment 86 by godzillatemple

Empathy is what lets us feel that the suffering of other people (or animals) is a bad thing, since we wouldn't want to suffer in the same way. And, therefore, whatever action causes that suffering innately feels "immoral" to us, from a purely evolutionary standpoint.

Evolution takes tens of thousands of years. If a concern for strangers came purely from evolution, you’d expect people from the Middle Ages to have basically the same sense of morality that we do. They didn’t. Most of them we’d consider vicious monsters. Human and animal suffering was not considered wrong, it was considered among the most popular forms of entertainment. How would their “innately” moral genes let them enjoy cat burning or breaking on the wheel so much? Morality takes reasoning.