I think that there are a lot of assumptions in that chain. When you or I ask why did we make a decision X we can formulate answers but, for my account, I don't have access to all of the components of my thinking - I cannot articulate what I feel is really going on. I think that randomness in the universe is very hard to account for too - I was impressed by an essay that Scott Aaronson wrote about this : https://www.scottaaronson.com/papers/giqtm3.pdf but I have read it several times and I am afraid I don't really understand it.