[millstone]

A silver atom's angular momentum is aligned based on the field in a Stern-Gerlach device. This alignment determines how these atoms react to a future magnetic field. Therefore a silver atom's angular momentum is deterministic. But it's not.

A totally deterministic universe would have been a lot simpler. Why go through so much trouble?

[gpderetta]

Why there should be a why?

[whatshisface]

You don't get to know in advance which questions will pan out into answerable ones. You could answer "why should there be a why" to literally and question about why. In fact, you could have said that about the motion of the planets, right up until Newton - which shows that the category of things that can be answered like that contracts over time.

[gpderetta]

That's a how, not a why. Asking why is it worth the trouble ascribes intentionality to the universe where none is expected