Full Idea
Causal accounts of knowledge are all very well in their place, but if they are put forward as general theories, then mathematics refutes them.
Gist of Idea
General causal theories of knowledge are refuted by mathematics
Source
David Lewis (On the Plurality of Worlds [1986], 2.4)
Book Reference
Lewis,David: 'On the Plurality of Worlds' [Blackwell 2001], p.109
A Reaction
You might have some sort of notion of an abstraction from causation which mimicked it in the mathematics case. Lots of things seem to be 'forced' in mathematics. Call it 'ersatz causation'. Necessities are enforcers.