In order to avoid the possibility of granting the reality of "mental existents," Hall, on page 153, speaks of intentions as dimensional (or, as he had written earlier, of having the nature of being an aspect of something else). He writes:
I have already suggested an escape from this by confining 'events' to physical happenings, some of which (certain neural ones) have an intentional dimension.
This is a position that Walter on this list has sometimes espoused himself. Hall goes on:
We could now add to this that when we loosely speak of a total mental event or state, such as is involved in an emotional experience, what we correctly refer to is a total cerebral event with all its intentional complexity, from which perceptions can be considered as abstractions.
This raises the interesting question of how we are to think about whatever it is that we consider the core feature of what we call "consciousness" or "mind" or "the mental." For Hall, apparently, the core feature of consciousness is intentionality, the condition of being about something. Hall seems to be saying that this state or condition (let's call it "aboutness" to distinguish it from "intentionality" when that term means the intentions which prompt us to action) is either the key feature of consciousness itself or is, in fact, just what we mean by consciousness. So the question must be just what this thing called "intentionality" qua "aboutness" is?
TruthHunter raised the issue of intentionality not long ago when he asserted that we can have "experience" (another recognizably distinguishable feature of what we call "consciousness") without it being about anything. In this sense he seems to be suggesting that the presence of intentionality is not critical to asserting the presence of consciousness. Presumably, though, he thinks that the presence of experience, itself, is. So for TruthHunter consciousness is experience while for Hall it's intentionality (or at least consciousness must include intentionality for it to be dubbed "consciousness").
Setting aside, for the moment, the different ways the terms may be used in the case of these different positions, and the possibility that Hall and TH simply mean different things by "consciousness") we ought to look a little more closely at this notion of intentionality qua aboutness. What does it actually consist of when we think about it or refer to it in discussions like this -- and does it make sense to suggest that it's a unitary, unanalyzable feature of whatever it is we mean by "consciousness"?
Hall seems to be making the claim that it is just that sort of thing, that it is an unanalyzable basic that just happens to occur as a "dimension" or aspect of some brain events though, in fairness, when invoking this notion in relation to explaining emotions, he suggests that it looks like something that is a system level feature (an occurrence that results from the interplay of multiple brain events in a certain way). As of now I am only about two thirds through his book and so I don't know if his position changes further on, but one thing I note is that he doesn't seem to make much of the differentiation between speaking of intentionality as a dimension (or aspect) of some brain events and speaking of it as a dimension (or aspect) of some combinations of brain events. Allowing for the latter, he seems to have nothing so far to say about whether or not the latter is the only way what we are calling "intentionality" here could occur. Thus he appears to leave open the possibility that he agrees with the notion, sometimes put forward by Walter, that intentionality is a special sort of property that belongs to some brain events and not others.
To get at this, we need to consider what intentionality in this sense is. To be about something requires a subject -- a looker, a listener, a smeller, a taster, a toucher, a thinker. In sum it requires a consciousness (one that does the foregoing). Thus aboutness seems to be a characteristic of everything the conscious entity does. All those things together we sometimes call "experiencing," having experiences. So consciousness is a necessary precondition for intentionality. But can we have experiences without intentionality as TH has suggested? What would that "look" like? What would it be like to experience without having something we are experiencing? Does that possibility even make sense? It's been suggested that we can think abstractly (without any particular object of any visualizable sort in mind) and Hall, himself, has suggested that we sometimes think we are having emotions which are not about anything (though he dismisses that possibility after some further consideration).
Perhaps the idea of thinking abstractly, thought as "pure thought," is what TH has in mind when he asserts that we can experience without anything being the object of our experience. In my own experience I have done Zen meditation for a number of years where the avowed purpose was to "just sit" and by doing so "empty the mind," stop one's thinking, the endless association of thoughts (consisting of notions, images, feelings, perceptions that occur in us as part of the stream of consciousness). The Zen practice aims at clearing the mind, wiping the dust of illusion away from the mirror of mind so that it is clear of anything but a deepseated awareness of . . . what? Awareness of pure awareness? An empty state of being? Pure being?
I cannot attest to that state though I have heard others talk about it. In my own Zen practice I have experienced various states including that of patiently watching the flow of my own thoughts, counting my own breaths, sometimes hallucinating and, not infrequently, catching myself sliding into sleep (fortunately I never fell over and so embarrassed myself among my fellow Sangha members). In none of my experiences have I ever discovered myself in a state of experiencing without experiencing something. Indeed, just to think about discovering myself in that state would, I expect, count as experiencing something (the awareness of experiencing without experiencing something) in which case it would seem to be a contradiction in terms. From this I would say that it's unlikely, if not impossible, that anyone could experience experiencing nothing. At best, I expect, one could reach a stage of calmness, of settled thoughts where the random flow of mental images and such is slowed down or dampened. But as long as one is conscious it seems a contradiction in terms to suppose that one could experience without experiencing something.
So intentionality, the condition of being about something, when understood as more than simply being a conceptual feature (something we do only via conscious thought), seems to be an inseparable feature from what we mean by "consciousness." But, if so, is it one of several features consciousness has or is it the one and only feature and so equivalent to what we mean by "consciousness"?
If all the features we recognize as part of what we mean by "consciousness" can also be seen to involve intentionality, then the latter answer seems right. That is, intentionality is, as Hall seems to be suggesting, the central and primary feature whose presence is always essential for consciousness to occur. But then is it, as he also seems to suggest in the quotes I gave above, unanalyzable, just a feature which some, as yet unspecified physical events in brains happen to have? Or does his suggestion that we need to look to the greater complexity of system level brain activity in order to account for the intentionality of emotions (because emotions, he claims are also about things) lead to a more Dennettian picture, i.e., that we are dealing here with a system level feature exclusively -- that intentionality is not, itself, a feature of particular physical events per se, but of particular combinations of them, systems of interacting events which look rather like information processing operations?
If that's so, then a functionalist account of consciousness, of what it means to have (as in what constitutes) a mind, seems right.