What's a cause?

(Half post / Half bleg)

There are many relations of making true. At the limit, we have material conditionals. But there are also causal relations, constitutive relations, and presumably more.

Now, with respect to something like constitution, I can see how this relation says more than a material conditional. It says that the parts come together to make the whole true, and we have a pretty good independent grasp on the concepts of "part" and "whole". So I can understand why "atoms constitute physical objects" says something more than the material conditional "if you have some atoms, then you have a physical object".

But what about with cause? What makes "A caused B" more specific than "if A, then B"? Tempting suggestions involve reference to temporal order and spatial proximity. But I take it that these are not necessary for a relationship to be causal, since I thought modern scientists were happy to claim that backwards causation and causation at a distance were possible (wikipedia confirms). I don't think it would be right to accuse them of conceptual confusion.

So - and here's the bleg - what is it that makes a causal relation more than a material conditional? References to literature are more than welcome. (For the Ethicists: This is interesting since it's not clear what the debate about "reasons as causes" is actually about unless we have an answer to this question.)