Is there any coherent non-religious argument that shows that the appearance of life on the universe is a "good" or "valuable" thing? It seems to me that something is valuable iff there's somebody who values it. So life would not be valuable when it does not exist, but it would become valuable when it does exist? Would it value itself? I'm not sure if this circular reasoning, or there's some solid ground. What would be some standard literature on this kind of issues?