Comment 106 by parkerjwill :

As others have pointed out, the better question is, Where do morals themselves come from? It's of no ultimate value to seek an answer to where Marry gets her morals, or where Tom the Chimp gets his, because this question is relative - it will repeat ad infinitum: Where does Marry and Tom get their morals?

No. Compare what happens if we substitute something a little more obvious:

Where do opposable thumbs themselves come from? It's of no ultimate value to seek an answer to where Marry gets her opposable thumbs , or where Tom the Chimp gets his, because this question is relative - it will repeat ad infinitum: Where does Marry and Tom get their opposable thumbs ?

In the case of thumbs the answer is clear. As you go back along the line of ancestors opposable thumbs will change into something else. Something less complex as the animals become less complex and arms change to fins and we head back to the first chordates.

It's called evolution. Things change and develop. The basic instincts underlying morality just as much as thumbs, feet, hands, eyes ...

There is no "ad infinitum" or infinite regress problem here.

Michael