Humans don't have such a capacity. The notions of 'good' and 'evil' have historically been in flux and went through many huge changes. Modern humans consider the typical behaviors of past humans as 'evil'.
Vikings - rape after conquering is good. People today: that's evil.
India until 2 generations ago - arranged marriage is good. Today that's evil.
Homosexuality - has oscillated many times between good and evil. In fact, different geographic regions will still have polar opposite views on this today.