[Bork]

Determinists assume that the Principle of Sufficient Reason is true. They think a causal chain goes to back to the first event, hence everything is determined.

Leibniz’s Formulation of the Principle of Sufficient Reason:
No fact can be real or existing and no statement true unless it has a sufficient reason why it should be thus and not otherwise.

This is a poor assumption. Here is a short excerpt from a paper I wrote this last quarter that explains why:

Many things do appear to have sufficient reasons but that does not justify the belief that all positive facts have a sufficient reason. People are inclined to believe PSR because our brains are built to identify patterns and relationships. When we observe a phenomenon we assume that there is an explanation or reason for it. We do this not for any good reason, but because that is how we are wired. It is a useful survival trait to believe everything has a reason, because it leads us to search for reasons. In our quest for reasons we often make useful discoveries.