Many people like to say that certain phenomena cannot happen because of the laws of physics. Letting aside the issue of whether some phenomena are really impossible for whatever reason, I'd like to investigate the basis for the notion of immutable, absolute laws. There are three things I don't understand: 1 - What reasons are there to think the universe is ruled by absolute laws? 2 - What reasons are there to think those laws do not leave room for exceptions? 3 - Above all, what reasons do we have to think we know what those rules are? It seems to me the notion of "laws of the universe" is merely a belief. Like all beliefs, it has some supporting evidence, but also like all beliefs, it lacks rational justification. That is how I see it anyway. Any comments?