For those who say there is no God, I think the problem is of definition. There are pantheists who believe that God is synonymous with Nature. Spinoza and Einstein were among these. Let us suppose for the sake of argument that there is nothing supernatural about this universe. Then everything that exists would necessarily be a part of Nature – even mankind. If everything that exists is a part of Nature, Nature by necessity possesses all the qualities of everything that exists. Let’s take the example of mankind: Man has qualities of life, intelligence, knowledge, power and purposefulness. If Man is simply a part of Nature, then it is Nature itself which ultimately possesses these qualities. We are forced to conclude therefore that Nature is alive (possessing life), intelligent (possessing intelligence), purposeful (possessing purpose), all-knowing (possessing all knowledge), all-powerful (possessing all power) and so forth. How is this any different than a god or even God?
There are only two logical ways of looking at Nature: 1) Nature is that which is apart from the supernatural; and 2) Nature is everything which exists within this universe. The first presupposes the supernatural which automatically allows for God or gods. The second must allow that Nature itself possesses all the qualities of God or a god. In either case, at least one god is inferred. And unless we have reason to suppose more than one god, then we should assume the simplest conclusion that there is only one God.
The precise definition of God may certainly vary from person to person or religion to religion but that is purely semantics. Whether the Supreme Being or merely a superior being, God or god, it exists one way or another.