What does you can't have it both ways mean?

Answer 1

It means "you can't have your cake and eat it too." In other words, once you cut the cake to eat it, you can no longer admire it as a beautiful whole. But since part of the whole purpose is to make something to eat rather than admire, we cut cakes and eat them.

You cannot be eating the cake and be admiring the whole at the same time. You can't have it both ways, by definition