One view of causation is deterministic: A causes B means that on any occasion in which A occurs, B occurs. An alternative view is that causation is probabilistic: it means that given A, the probability of B is greater than some criterion, such as the probability of B given not A. Evidence about the induction of causal relations cannot decide between these two accounts, and so we examined how people refute causal relations. Three experiments showed that they tend to be satisfied that a single counterexample of A and not-B refutes claims of the form, A causes B and A enables B. But, as a deterministic theory based on mental models predicted, when participants required more than one refutation they tended to do so for claims of the form, A enables B. Similarly, refutations of the form not-A and B were more frequent for enabling than causal claims. We interpret these results to imply that causation is a deterministic notion, and that causation and enabling conditions are distinct concepts.