Causal theories of meaning have trouble dealing with certain areas of discourse. My words 'five' and 'the empty set', for instance, don't seem to get their meanings from my having certain causal relations to the number five or the empty set.
So what would happen if we stopped thinking in causal terms we thought instead about explanation? Some theory along the following lines would presumably be the result:
S's term T means M iff there is the right kind of explanatory dependence between M (or Ms) and S's use of T.
Of course, the devil's in the detail of trying to say what the 'right kind' of explanatory dependence is. But explanation has often seemed to me to offer at least prima facie promising ways out of trouble in places where talking about causes, counterfactuals or necessitation looks initially plausible but eventually runs into difficulties. Theories of knowledge are one place where this idea has an application, as I argue in my CJP paper. I also think Simon Blackburn is right to move away from talk of what "guarantees" success towards talk of explanations of success, in trying to develop a more promising form of success semantics.
I'm glad to see that Simon's success semantics paper is now available online; I remember with pleasure an exceptionally productive afternoon seminar in Cambridge on this topic, where Simon, Anandi Hattiangadi, Steve Butterfill, and I thrashed out the issues. (Aside: many congratulations are due to Anandi on her new continuing job in Oxford!)