All this talk about "conscience" is rot.  Moral beliefs are pumped in from outside.  Some people never acquire any at all.

You mean the famous "people without a conscience."  But there is a difference between guilty knowledge and guilty feelings.  Not everyone feels guilty for murder, but everyone knows murder is wrong.  Precisely because they have guilty knowledge, wrongdoers who lack guilty feelings show other telltales, such as depression, a sense of defect, a compulsion to rationalize, or a puzzling desire to be caught.  The suicide rate among sociopaths is also higher than in the general population.

So maybe we do all have conscience.  But I still think it's pumped in from outside.  If I want to teach Billy that hurting people is wrong, I just say "Billy, don't hurt people. It's wrong."

That's a very good thing to tell him, and I strongly recommend it.  But what do you say when he asks "Why is it wrong?"

I say "It just is."

So do I, but that's just my point.  The reason you can draw that fact to Billy's attention is that once his attention is drawn to it, he can see it for himself.  But suppose he didn't.  Suppose he didn't even know the meaning of wrong.  What would you do then?

I'd tell him "Wrong is what you ought not do."

By itself that would teaches him only that "wrong" and "what you ought not do" mean the same thing.  It wouldn't teach him what same thing they meant.  If he already knows what "ought not" means, then you've given him a synonym.  If he doesn't know what "ought not" means, then he doesn't know what "wrong" means either.

In that case I'll tell him "Wrong is what you'll be punished for."

Come now, you don't believe that yourself.  Generally speaking, wrong should be punished.  But if a wrong goes unpunished, does that mean it isn't wrong after all?

Point taken.  I'll teach him "Wrong is what you OUGHT to be punished for."

Then you've merely led him in a circle:  Wrong is what it would be wrong not to punish him for.  You've explained wrong in terms of wrong.  The explanation presupposes the thing you are trying to explain.

Then how do you teach him what wrong means?

We can teach first principles in a sense, but we can't "pump them in."  The mind is so designed as to acquire them on its own, as the eye is designed to see on its own.  What we call teaching only helps the process along.  When we instruct and discipline the child we are only calling his attention to the first principles, giving him words for them, building on them, extending them, and reinforcing them with praise and punishment.  Billy learns the meaning of the word "red" because whenever something is red, I say "red."  He learns the meaning of the word "same" because whenever two things are the same, I say "same."  And he learns the meaning of the word "wrong" because whenever something is wrong, I say "wrong."  But a child without the rudiments of synderesis could not be taught the meaning of the word "wrong" for the same reason that a child without sight could not be taught the meaning of the word "red" and a child without the power of comparison could not be taught the meaning of the word "same."  The child has to be able to see for himself what I am drawing to his attention.

A Dialogue on Natural Law, Part 6