 (ii) Irrelevance. A condition that is invariably followed by some outcome may nonetheless be irrelevant to that outcome. Salt that has been hexed by a sorcerer invariably dissolves when placed in water (Kyburg 1965), but hexing does not cause the salt to dissolve. Hexing does not make a difference for dissolution. Probabilistic theories of causation capture this notion of making a difference by requiring that a cause make a difference for the probability of its effect.