What is right and wrong or how can people know that there is a right and wrong?
The concepts of right and wrong are part of ethics or morality. Every society which we can examine through written or oral records seems to have some concept of right and wrong. While ethical codes vary tremendously from one society to the next, all societies seem to possess some form of ethical codes. We cannot say whether that means right and wrong exist in some abstract, non-human fashion, but rather that it is a universal characteristic of how we look at out world. The inability to perceive right and wrong in some form is considered a form of mental illness or sociopathy.