Is creation proof of God?

 If one accepts the definition of God as the creator of creation then it’s definitional proof. It depends on a person accepting the definition. If someone disputes the definition then a valid reason for rejecting the definition is needed.

If there is no valid reason to reject the definition then it’s an arbitrary decision which is not rational and eliminates any rational discussion.

So who defines God? Since atheism is a reaction to the proposition of God existing, it has no definition of its own and has to engage with other’s definitions. If a person rejects every offered definition of God, they should have something against which to compare any definition in order to validate or invalidate it. If an atheist offers their own definition of God which is contrary to thousands of years of philosophical and theological use of the word, there’s no reason to accept it as a valid benchmark to evaluate any given definition. It’s idiosyncratic and arbitrary so cannot be the basis of fruitful discussion.

Someone can say that God could have created the ‘creator of creation’ which is a valid objection to God being the ‘creator of creation’ but not a valid objection to God existing if God is defined as uncreated.

Or, someone can challenge that the universe was created and instead posit that it eternally exists as a universe, without ever coming into or going out of existence in cycles.

That would mean the universe has existed eternally as a changing universe, which raises another problem. The universe is constantly changing. If what we call reality is nothing more than this continually changing succession of states, then there is no fixed reality underlying those states. Reality becomes whatever happens to exist at a particular moment, and then that reality changes into something else.

Once reality is reduced to temporary states, the word "reality" is robbed of any ultimate meaning. We end up saying that nothing is ultimately real except the claim that nothing is ultimately real, which ironically gives us one thing that is supposed to be ultimately true: nothing is ultimately real.

And there is a further problem. If nothing is ultimately real, then the proposition that the universe is an eternally changing reality cannot itself be grounded in anything ultimately real. Is that proposition itself ultimately true? If it is, then something has been identified as ultimately true, contradicting the claim that nothing is ultimately real. If it isn't, then why should we regard the proposition as an adequate account of reality in the first place?

These may be fun philosophical concepts to play with but if taken seriously, they offer a pretty poor blueprint for living life.

Defining God as the eternally existing origin of all existence is nice. Something has to be the eternally existing origin of all existence so that is not rationally debatable, if I define that something as God, the only way to deny God’s existence is to say nothing exists which is obviously problematic, or to object to using God as the word to describe what must exist. Which brings us back to who defines God?