You can define the morally good as: that set of behaviors which you have many strong reasons to train others to do, especially through rewarding them with praise. Similarly, morally bad (or "evil") can be defined as: that set of behaviors which you have many strong reasons to train others not to do, especially through negatively reinforcing them with condemnation. We are all subtly training each other, especially through praise and condemnation. But especially, parents tend to train children, and in general, older members of a social group train the young. Thus training can pass down from generation to generation. But younger people, especially from the ages of about 3 to about 11, are more susceptible to training than older people. After this point, the rate of acquisition of training slows, and humans may even become resistant to training. Old people may become very incapable of, or very resistant to, new training. That might be a bug, or it m...