But I answered it! Here the complete citation, not just the first part:
But they are! But again you are using a vague word, 'responsible'. (you used 'driven' before, also vague). What is this 'responsible'-relationship? You say it is causation, I say it is supervenience. So my answer to your question is simple: there are no other variables. But there are different ways we can look: from the low levels like atoms, molecules, and neurons; or at the higher level of persons, (true) beliefs, actions, motivations, (free) will etc. The latter we are using in day-to-day life, the former by neurologists, biologists etc.
And to epiphenomalism:
In the fist place, I highlighted the important word: 'cause'.
In the second place you left out what more is written there, immediately after your citation:
So what is this: mental phenomena are caused by physical processes, but they miss the other half of what causality is: that events, mental events in this case, are caused, but cannot cause other events themselves?
And isn't this just evading:
I actually haven't. I've said "it depends on how you define it."
If not causation, what is it? Or what is then the applicable concept of causation, according to you?
I agree with your second sentence. But you have found another word to describe the relation between physical processes, which is again more vague, 'rooted'. I was more specific: it is a relation of supervenience. And everything you wrote about your views on the matter, show for me that you mean causality. And if you want it or not, this stance is called 'epiphenomanilism', with all its problems.
From the same Wikipedia article: