[Serious] Could an omnipotent and omniscient god prove that he was God?

[Objectivist]

It doesn't.  That's not it's job.  It's job as I said is to identify a general truth on which other truths rest.  How you get to further knowledge is by the same process of looking at reality and identifying what you perceive.  We don't just recognize that existence exists and deduce everything else from that recognition.  That's not the way knowledge works.  We learn almost everything inductively.  Only after we've done induction can we apply that inductive knowledge to particulars.  We can't say existence exists and then jump straight to why/ how does the local universe exist.  What is a universe, what does local mean?  What is causation?  Before we get to those concepts we've already made a long chain of discoveries that lead up to those questions and when we get to them we answer them, if they are not improper questions, by looking to reality.  We don't start with nothing and then seek a reason for why existence exists.  You have to start with existence and then see what else you can learn about it.  The question of what came before everything and what caused it is an improper question because it makes use of stolen concepts.  To steal concepts is to make use of them while ignoring their roots including the recognition that existence exists.

You mean like poposing a being whose essense and existence are the same?....sounds very familiar. Could be a stolen concept, yes?

Sorry, Neo-Scholastic, but I have no idea what you mean.  I did not speak of essences.  You wondered how the axiom of existence explains how/ why particular existents exist.  I was simply pointing out that it doesn't.  It's simply the first fact we become aware of and in the act of grasping that fact, we grasp the fact that we are conscious.  The question arises from these two recognitions which one of these has primacy, consciousness, or existence?  The answer is that existence has primacy and if existence is primary then it is eternal and uncaused.  The stolen concept arises from positing a cause in the absence of existence. The concept of a cause presupposes existence.  Now if you want to know what caused some particular existent within the universe then the answer is causality like everything else apart from existence qua existence.  The notion that some being exists outside existence and caused existence as such is philosophically incoherent and makes use of stolen concepts that are fallacious.