There is some kind of mental representation, though, otherwise it wouldn't be distinguishable from other concepts.If we take this billiard ball causation to be an exact kind of a posteriori conception of causality, we notice that even in this very sentence where I have used the word "causality" (bolded) that that concept (causality) is not the same as the billiard ball concept. With the former (billiard ball conception), clearly we have a mental image of a sequence of events. That is not true of the latter.
The conception of causality, no matter how it is defined, refers to all causal events, as opposed to one particular imaginable event. Even the conception of billiard ball causality is a class of a wide variety of causal events, billiard balls being just one example that was more or less arbitrarily used to label the class. The conception of billiard ball causality is in the same boat as generic causality in that it can't really be imagined concretely without being applied to a specific situation. But I do think that concepts, even abstract ones, each have a mental representation associated with it. The mind appears to us as more than mere words.
I think a thinker shouldn't focus on words, thinking that he can reason with them, but keep clarifying and molding his underlying mental representations, no matter how indescribable they are and how nonsensical they may seem, and use those for the basis of reason instead. We really ought to free ourselves from the seduction of words!
We need to look not at the words used to communicate a concept, but the concept's meaning and its impact on the mind--to deepen the impact of worthwhile meanings by meditating and reasoning about them and to mitigate the impact of worthless meanings by not thinking about them, or thinking truthfully about them at least. That's the concept of causality put into practice.