Full Idea
A given type of state may be causally efficacious, but not as efficacious as an alternative states, so it is not true that even a direct cause need raise the probability of its effect.
Clarification
'Efficacious' means highly likely to have the effect
Gist of Idea
The actual cause may not be the most efficacious one
Source
Michael Tooley (Causation and Supervenience [2003], 6.2.4)
Book Reference
'The Oxford Handbook of Metaphysics', ed/tr. Loux,M /Zimmerman,D [OUP 2005], p.424
A Reaction
My intuition is that explaining causation in terms of probabilities entirely misses the point, which mainly concerns explaining the sense of necessitation in a cause. This idea give me a good reason for my intuition.