Reply to Fairley and Manktelow's comment on "Naive theories and causal deduction".

Fairley and Manktelow (1997) have mistaken an error of presentation for an error of substance. My causal theory remains the same: Causal reasoning scenarios that require the reasoner to decide whether or not an effect will occur in the presence of a viable cause trigger consideration of disabling conditions—that is, factors that could prevent the effect from occurring in the presence of a viable cause. Scenarios that require the reasoner to decide whether or not a particular cause has produced an observed effect trigger consideration of possible alternative causes. The data reported by Cummins (1995) and Cummins, Lubart, Alksnis, and Rist (1991) are consistent with this theoretical analysis.