Thanks for responding to my OP, M.U. I appreciate it! I think you are capturing something valid about a different structure than the one I have in mind. I'm not looking so much at what X means as a word, but how event X is explained.
--Why is there a world?
--Because [for instance] God created it
--Why did God create the world?
--Because he had love to give [for instance]
--Why did God have love to give?
Or we can leave God out and just look at the hope for a scientific theory of everything, from which all of the other laws can be derived. We could use this theory of everything to answer lower-level why questions about particular contexts. But I can't see how the TOE or top-level necessity avoids a "just because" status. I'm aiming at what I perceive as the apparently necessary contingency of (top level, most general) necessity. I could say more, but I'd rather develop it in a conversation. For me it occurred as sudden insight, in the context of theological (apparent?) explanations. But Weinberg has wrote about this insight applied to physics.
"Can Science Explain Everything? Anything?"
https://ned.ipac.caltech.edu/level5/Sept06/Weinberg/Weinberg.html
Here's a quote:
"Within the limited context of physics, I think one can give an answer of sorts to the problem of distinguishing explanation from mere description, which captures what physicists mean when they say that they have explained some regularity. The answer is that we explain a physical principle when we show that it can be deduced from a more fundamental physical principle....
We hope that in the future we will have achieved an understanding of all the regularities that we see in nature, based on a few simple principles, laws of nature, from which all other regularities can be deduced. These laws will be the explanation of whatever principles (such as, for instance, the rules of the Standard Model or of general relativity) can be deduced directly from them, and those directly deduced principles will be the explanations of whatever principles can be deduced from them, and so on...
Finally, it seems clear that we will never be able to explain our most fundamental scientific principles.
(Maybe this is why some people say that science does not provide explanations, but by this reasoning nothing else does either). I think that in the end we will come to a set of simple universal laws of nature, laws that we cannot explain."
"By this reasoning nothing else does either" is exactly what I'm getting at.