To answer a question about the “why” of Creation can, philosophically, be proven to be impossible.
You get to a point where you are asking questions that are unanswerable, not because we lack knowledge, but unanswerable by definition.
But perhaps we can say this much:
When you speak about the world from this point of view, it is, so to speak, a tour de force, an experiment in existence, an experiment of what I might call “conquering the utmost case.”
So in a way, existence in any other world is not “proof.”
Proof in the utmost case occurs only when you can do things under the worst of circumstances.
If I want to test a new car, the way that I test it is not on the smoothest of roads, under the best conditions.
To have a real road test to prove that a car really works, I have to put it under, and I would say this again, the worst conditions in which there is yet hope.
I cannot test it by driving it off a cliff, but I can test it on the roughest terrain where I must come to the edge of a cliff and have to stop.
How is a new plane tested?
They put it under nearly impossible conditions, which the plane must withstand.
Otherwise the whole experiment doesn’t prove anything.
The same with Creation.
Creation would have been pointless unless it was a Creation under precisely these difficult circumstances.
So I am saying, theologically speaking, that the worst possible world in which there is yet hope is the only world in which Creation makes sense.”
–Rabbi Adin Steinsaltz
From “The Mystic as Philosopher: An Interview with Rabbi Adin Steinsaltz,” in the Jewish Review conducted by Sanford L. Drob and Harris