The only part of nature that contains any hints about morality is man, humankind. From the outside, there would be no way of seeing morality. You cannot look at the way things are and have a sense of how they should be. But as humans, we can do more than observe the natural world, we can look inside ourselves, and when we do we find that we have the belief that some things are right and other things are wrong. In fact, we are so aware of this thing inside us that cares about right conduct that we feel the need to make excuses for whenever we do wrong. If we break a promise, we say, "It was too difficult to keep", when we steal we say, "The business owners are filthy rich, it hardly even hurts them, and I really need this". But this sense that humans have cannot be observed. I suppose this is where I am being illogical; I am one person, I experience this strange sense of "ought", and from talking to other people, I have come to believe that everyone is getting a similar experience of "ought" that I am getting.