In his paper What is consciousness? (1981), D.M. Armstrong – Professor Emeritus at the University of Sydney and one of the founders of functionalism – brings up an example of what sometimes happens to long-distance truck-drivers, to distinguish between ‘perceptual consciousness’ and ‘introspective consciousness’:
“After driving for long periods of time, particularly at night, it is possible to ‘come to’ and realize that for some time past one has been driving without being aware of what one has been doing. The coming-to is an alarming experience. It is natural to describe what went on before one came to by saying that during that time one lacked consciousness [i.e., lacked some kind of consciousness different from perceptual consciousness].” (p. 610, Philosophy of Mind, ed. John Heil, 2004)
He then introduces the notion of introspective consciousness:
“Introspective consciousness, then, is a perception-like awareness of current states and activities in our own mind.” (p. 611)
How does this tie into ‘philosophical zombies’? He continues at a later point in the paper:
“There remains a feeling that there is something quite special about introspective consciousness. The long-distance truck-driver has minimal [a technical term Armstrong uses to mean some sort of mental activity] and perceptual consciousness. But there is an important sense, we are inclined to think, in which he has no experiences, indeed is not really a person, during his period of introspective unconsciousness. Introspective consciousness seems like a light switched on, which illuminates utter darkness. It has seemed to many that with consciousness in this sense, a wholly new thing enters the universe.”
The language Armstrong uses here is reminiscent of the language David Chalmers, writing in The Conscious Mind (1996), uses to describe philosophical zombies:
“A [philosophical] zombie is just something physically identical to me [i.e., acts the same, talks the same, and so on – is the same as far as we can physically tell], but which has no conscious experience – all is dark inside.” (p. 96)
The idea is not that philosophical zombies have an experience of darkness – rather, it is a figurative way of speaking about a lack of what I would call subjective experience, or what Chalmers calls ‘conscious experience’ above. Yet, it is suggestive of a link between how Armstrong is conceptualizing ‘introspective consciousness’ and how Chalmers is conceptualizing ‘conscious experience’.
Armstrong seems to be conflating subjective experience with introspective consciousness. Chalmers picks up on this in his 1996 book The Conscious Mind:
“Armstrong (1968), confronted by consciousness [i.e., subjective experience] as an obstacle for his functionalist theory of mind, analyzes the notion in terms of the presence of some self-scanning mechanism. This might provide a useful account of self-consciousness and introspective consciousness, but it leaves the problem of phenomenal experience to the side. Armstrong (1981) talks about both perceptual consciousness and introspective consciousness, but is concerned with both only as varieties of awareness, and does not address the problems posed by the phenomenal qualities of experience. Thus the sense in which consciousness is really problematic for his functionalist theory is sidestepped, by courtesy of the ambiguity in the notion of consciousness.”
I think Chalmers is right here, but he makes it sound like Armstrong uses the ambiguity in order to sidestep the problem. My sense from reading Armstrong 1981, rather, is that there is some sort of implicit identity between certain functional states and subjective experience, and so for him the conceptual distinction carries less weight. However, it seems Armstrong is also working through the conceptual muddle that many other philosophers and scientists were working through at the time, and hasn’t clearly distinguished the two aspects.
When Chalmers (Facing up to the problem of consciousness, 1995) pulls apart consciousness into ‘consciousness’ proper (i.e., subjective experience) and ‘awareness’, this is doing heavy work:
“Another useful way to avoid confusion […] is to reserve the term ‘consciousness’ for the phenomena of experience, using the less loaded term ‘awareness‘ for the more straightforward phenomena described earlier [i.e., causal or functional phenomena, such as the ability to discriminate, categorize, and react to environment stimuli, the integration of information by a cognitive system, and so on].” (p. 619, Philosophy of Mind, ed. John Heil, 2004)
The conflation of the two elements of this and related psychological or mental terms occurs throughout the literature, and leads to a ‘side-stepping’ potential for various solutions, of which Armstrong is but one. However, it is only by making the conceptual distinction explicit, and then showing how an (functional in this case) identity is problematic, that the real problem becomes apparent.