The root cause of everything is the laws of physics and, to the extent it is a separate issue, the initial state of the universe.

Or, from a different epistemological viewpoint, the root cause of everything is God’s will.

Ascribing importance to intermediate causes is highly subjective, even assuming they can be reliably determined.

> The root cause of everything is the laws of physics and, to the extent it is a separate issue, the initial state of the universe.

Only if you think that the laws of physics are deterministic, I guess.