Thank you for this most thought-provoking and insightful essay-post! IMO, you are dealing with the very "essence" of understanding the fact of creation.
Early on in your essay, you made a statement that (IMO) demands clarification, qualification, and expansion:
" That there was a beginning means there is no infinite past."
Please allow me to add a qualification that makes the statement reflect both physical and Scriptural reality:
" That there was a beginning of this universe means it has no infinite past."
And, then, you proceed to discuss this universe (and clarify your above statement) in a most delightful and insightful manner...
Even philosophers and scientists who place no credence in Scripture have discussed the possibility of "other" or "parallel" universes.
And Scripture clearly indicates that there is a "place" of existence "beyond" the confines of this created universe. We believers usually call that existence, "Heaven".
And, since Scripture reveals that that "extra-universal reality" is where "I AM" "is", we must look upon both Him and His creation -- and His description of His creative acts in the 31 sentences in Genesis -- with perception that transcends our "earthbound" viewpoint.
...only God, beyond space/time and physical causation, can be the uncaused cause of causation, the first cause, The Creator of the beginning.Space, time and physical causation are not properties of God the Creator. They are properties of the Creation. Only God is uncaused.
Praise HIM for these insights He has given you to share with us!!
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...and that leads to my comments-to follow (on the attributes of "I AM")...
Too bad FR has no "Reply All" option... ;-(