 Determinism (understood according to either of the two definitions above) is not a thesis about causation; it is not the thesis that causation is always a relation between events, and it is not the thesis that every event has a cause. If the fundamental laws turn out to be probabilistic rather than deterministic, this doesn’t mean that there is no causation; it just means that we have to revise our theories of causation to fit the facts. And this is what philosophers of causation have done; there are probabilistic versions of lawful entailment theories of causation, of counterfactual theories of causation, and so on, for all major theories of causation (see the entries on the  metaphysics of causation  and  counterfactual theories of causation).  It is now generally accepted that it might be true that every event has a cause even if determinism is false and thus some events lack sufficient causes.