The theory of relativity would not be called a theory if it were a fact. It is a working model that will be replaced by another one like all others have been.
Indeed, the methods whereby the physical creation is studied involves many things which are themselves not physical: logic, math, physical laws, etc.
They are methods and tools for connecting the dots.
According to Einstein, the one who cannot sense the mysterious is dead or blind.
That is his religious opinion (by his own admission).
The following passage points to the obvious [sic] fact [sic] that there was a beginning, a first cause
If you can postulate an eternal God, why not an eternal universe? If God doesn't have a beginning why not the universe? Why is it an "obvious fact" with the universe but not with God? Just because?
For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, [even] his eternal power and Godhead; so that they are without excuse: - Romans 1:20
Oh, please...If they are invisible then they cannot be seen. And the things that are made don't understand jack about them, but are grasping at straws to justify sticking to their theories.
Like I said, axiomatically assuming God's existence is valid, but it is not a proof without excuse. Besides, God is such a nebulous concept that to even speak of God as an agreed-upon definition is an exercise in futility.
In discussion and apologetics, this is rarely done. However.. For the purpose of a real, formal debate, it is necessary to define terms. And this is also necessary, obviously, for a logical proposition, for an axiom. This is the direction you're taking.
I've suggested before that a definition that can be used for these purposes is "the creative principle of the universe."
St John Damascene and other theologians would say that we cannot know all about God, but that we can know some. I think the suggested definition is not complete, but could be considered accurate and useful for a purpose. It's a partial definition but one I *think* most Christians, and most other religion's theologians would accept.
But, I wonder if the agnostic or atheist would accept it, or maybe they would grant that it exists thus negating the disagreement under debate.