No one can ever prove that (A) could have led to (C) rather than (B); nor can one, as it stands, prove that it could only lead to (B); because the only reality we have access to is the one in which (A) indeed did lead to (B). In the absence of cold hard proof, I am left with only intuition and faith.

I do not believe that, if we could rewind time and let it proceed again, anything different would occur. That's the long and short of it. That idea doesn't fill me with existential dread, because it quite literally changes nothing about how I inhabit the world – except that it gives me a poetic sense of contentment and soothes some fears.