@Ren
So on no account can intentionality be reduced to the cause-effect relation.
That's true, but that's extremely, extremely far from the point I was making/regardless of where it's arising, this misunderstanding is too major to not clarify quite significantly.
I think one big source of the problem is we have to distinguish the experience itself from the mental state (the way YOU are using "state" -- I'm not sure I made such a distinction, but you definitely seem to be). Many philosophical views are significantly
externalist about the content of a mental state.
These would say that the aboutness of the mental state is significantly determined by factors outside of the experiential components. In other words, it'll involve the very complex causal web the mental experience is part of, not just the experience itself.
All that's being claimed is that it's not obvious the metaphysical nature of the experience itself is playing a big role in determining the aboutness. In your post, you are underscoring that the aboutness may be determined by something more complex than a single causal relation.
Nobody disputes that among physicalists....most/all would say often there's at least a huge causal web the mental state fits into that is needed to understand the content of the state.
The example of visual stimulus is as good as any to illustrate the point, in that sure, in that case it was a single causal relation determining the aboutness, but the point is even if it's a complex web of causal relations that the experience is part of, that doesn't change the fact that it is this web/the experience being involved in a giant mosaic, NOT a very specific point about the metaphysical nature of the experience itself, that may determine the aboutness.
You mention the issue of whether a mental "state" has about-ness -- that's not the question quite. The way you're using state, you're likely distinguishing it from the experiential component alone. We both might even agree that the experience of tasting ice cream doesn't
itself come with an aboutness. What triggered that experience would have to play a role -- whether it was a machine stimulating the brain or whether it was an actual spoon of ice cream being placed in the mouth.
The burden is really to decide if the metaphysical nature of the purely experiential component (the qualia part) is essential to conferring intentionality.
My point was that one could be an
anti-physicalist about mind quite easily who thinks the latter. I'm not saying if I agree with those anti-physicalists, but I think this issue is controversial/one of the less clear.