Dot, I think that many people think about the things you've listed, and experience along with it a certain sensation. I'm going to call this sensation "existential angst", and because I'm also in before religion argument, I suggest looking up Kierkegaard's thoughts on the matter.
Alternatively one could go all buddhist philosophy and seek the ways to just "be".
Haha 'why is this post so boring', good one ngfan. But to answer your question, it probably ends up in a religious discussion. If you have religion, that is why you don't kill someone. If you don't believe in a god, then... you really have no reason not to kill anyone. Scary thought.
I don't know if I ascribe to the belief that everyone who doesn't believe in God thinks it is OK to kill someone (or that there is no reason not to). You know, morality is not owned solely by Christianity. Many other religions (and society in general) hold morals to a high standard, as do non-religious people.
That's true, but that still doesn't answer the question of why something exists instead of nothing. All it does is give reason to the pondering of the mystery and prove that we do, in fact, exist.
...actually formally speaking, self-referential arguments for existence don't prove anything because they beg the question. See Descartes' claim cogito ergo sum ("I think therefore I am". But personally I think it's simpler to assume we 'exist' and go from there.
Existentialism is a horrible concept in itself. It can both win and lose any arguement because it disproves everything you thought was true. However, there are certain truths that we must accept as fact, at least for the world we live in. The laws of physics are fact. We cannot change the way forces interact with each other. Rather, we can study these forces and learn how to direct them. However, this does not prove that our explanation was right, only that our method works. Take, for example, the theory of spontaneous generation. Flies were thought to spawn from rotting meat. However, it was proven that such was NOT the case in later experiments. However, the method worked - flies DID appear whever there was rotting meat. This is the basis behind doing any research at all, lest we remain ignorant. The correct explanation is important in that it allows us to apply the principles in multiple areas.
