What do we even mean when we speak of consciousness? As we’ve noted before, there are many competing and overlapping definitions, and in addition it’s pretty clear that the phenomenon itself is complex and that the word refers, in different contexts, to a number of different things.
A few years back, Thomas Natsoulas had a determined go at clarifying the position in his paper “Concepts of Consciousness”. For his framework he fell back on the old debating society standby of consulting the dictionary. You might ask whether this was necessarily the best way to go: lexicographers have their own priorities, after all. They typically aim to report the way a word is used; if it’s used in ways that are inconsistent or taxonomically incomplete, that isn’t a problem for them. On the other hand, the use of dictionary definitions does bring in an element of neutrality, and protects Natsoulas against any charge of skewing his definitions to support his own theoretical views: and the dictionary in question was no less a tome than the complete Oxford English Dictionary (OED), a mighty work of scholarship whose views on almost any subject are not to be lightly dismissed. Natsoulas himself says he sees merit in looking at ordinary, common-sense ideas, which can help remedy the potentially problematic lack of work by psychologists on the conceptual side.
The OED gives six senses of ‘consciousness’. The first, which we can call c1, strikes a modern reader as odd: it is knowing something together, joint or shared knowledge: con-scire as the derivation of the word suggests. There is a definite suggestion of the shared knowledge being a guilty secret, perhaps even an echo of con-spire. Although c1 is the ancient sense of the Latin root and seems to have enjoyed a brief revival in the seventeenth century it is no longer current and does not at first seem to offer us much enlightenment on the modern concept. Natsoulas, however, points out that it captures the idea of consciousness as a social, interpersonal thing. He quotes Barlow:
…consciousness is something to do with a relation between brains rather than a property of a single brain.
Barlow, it seems, went on to suggest that internal consciousness was a kind of ‘rehearsal for recounting’, which is interesting.
If we doubt that c1 is really important, I suppose we might ask ourselves what the state of mind would be of a human being who never at any stage since birth met another communicative entity. I don’t think I’d be ready to say that such a person could not be conscious, but their consciousness would surely be lacking in some important respects.
C2 follows on in a way: it is in effect knowledge shared with oneself, knowing that you know. This sounds like the HOT (Higher Order Theory) and HOP (Higher Order Process) theories which approximately say that a thought is conscious when accompanied by an awareness of that thought. It’s also reminiscent of those, like Dennett, who see the internalisation of talking to oneself as the origin of consciousness.
Natsoulas quotes Vygotsky:
A function which initially was shared by two people and bore a character of communication between them gradually crystallised and became a means of organisation of the mental life of man himself
It almost begins to look as if the OED has a rather cogent theory of consciousness.
C3 is awareness, of or that, anything, whether obects in the world or one’s own thoughts. Natsoulas insists there must be an object for this form of consciousness: even the thought that ‘I am having no thoughts’ actually has a content, he points out. Being conscious without content is in his eyes properly reserved for c6. He notes that the OED seems to include with c3 a veridicality requirement the claim is that if a man is aware of a bush, but thinks it is a rabbit, he is not really aware of the bush. Natsoulas, rightly I think, disagrees, insisting that even false awareness is still awareness. I think we must certainly preserve the possibility of being aware of something without having to have correct knowledge of its real nature.
I’m not sure whether the indirect awareness of memory falls into this category or the next, but there seems to be an overlap because c4 is, to adopt the OED’s Locke quotation:
…the perception of what passes in a man’s own mind…
which appears to be a subset of c3. Interestingly the OED seems to think that the primary use of c3 is awareness of one’s own mental contents, while using it to mean awareness of actual objects in the world is ‘poetic’. Natsoulas concludes that in this respect Englsh has moved on a bit since the OED last looked, but you have to admire the magisterial coherence of the OED view in which consciousness begins by being shared knowledge, becomes knowledge you share with yourself, in which form it is naturally about your own internal states, but by metaphorical extension can also mean your awareness of the external world.
I say c4 seems to be a subset of c3: perhaps as a result, Natsoulas says experimenters are often bedevilled by confusion between the two, claiming that a subject’s inability to report a stimulus shows they were never aware of it (whereas the subject can be aware of the stimulus withoug being aware that they are aware).
There might seem to be some dangers in the self-reference of c4, but Natsoulas points out that there’s no problem in well-managed higher orders. If there were a ban on higher orders, he argues, introspection could never get properly started.
c5 is not a form of consciousness but rather a set of all the occurrent and previous mental states which putatively make up the individual’s existence. This is the sense in which science fiction stories speak of your consciousness being transferred to another body, or to a machine. The OED gives us a quote from Locke:
If the same consciousness can be transferr’d from one thinking substance to another, it will be possible that two thinking substances may make but one person…
Natsoulas is quite happy with the idea that consciousness is not to be identified with the substrate, Locke’s ‘thinking substance’, but he raises some difficulties. What set of states is adequate to constitute a specific consciousness? Must it be all of them? That seems too strong, because if I were to lose one of my memories, I should not thereby lose my identity – I forget things all the time. Perhaps it has to everything I could recall – and some forgotten or unconscious things might still be shaping my mind. Worse, I can remember experiences yet fail to have the feelng that they are really my experiences.
Some would regard this defining set of mental states as the ego, or the ‘I’, which is a way of looking at it: but attempts to use a static central ‘I’ as the thing that pulls it all together are doomed in Natsoulas’ eyes. He thinks that with appropriate care we can use c5 and take account of the vivid and persuasive sense of an inner source without having to grant its ontological reality.
c6 is approximately equivalent to ‘awake’ and the opposite of unconscious. Searle, in typical commonsensical style, once used c6 as his definition of consciousness:
‘Consciousness’ refers to those states of sentience and awareness that typically begin when we awake from a dreamless sleep and continue until we go to sleep again, or fall into a coma or die or otherwise become ‘unconscious’.
Natsoulas takes this to be the kind of consciousness that has no requirement as to content: you could be conscious in this sense while thinking anything or nothing. In fact although the medical salience of the concept is clear, it seems too open-ended to be of much analytical use. We should certainly be willing to speak of a dog being conscious (or unconscious) in this sense, and I think we’d be willing to push that usage much further – certainly to fish and quite possibly to an ant in certain circumstances. We’re not, then, speaking of anything narrowly defined: c6 means something like ‘the state when whatever mental activity normally goes on during periods of activity, is going on’.
I think it is open to debate whether this OED-based six-way definition gives us sufficient tools to tackle the probem of consciousness. It does not seem to capture Ned Block’s distinction between a- and p-consciousness, more or less the distinction between the targets of the Hard and Easy problem: yet that is one of the most-quoted and used of definitions. I think we might also look for sharper and more useful distinctions between internal and external awareness.
Still, it is a useful exercise, and Natsoulas proceeds to do something with the results, positioning the six senses along four different axes: intersubjectivity, objectivation, apprehension and introspection (this seems to cry out for a diagram, though I appreciate that rendering a four-dimensional space graphically intelligible is a non-trivial matter.
Natsoulas makes little of this concluding exercise, presenting it as a kind of run-through to help get things clear. But it seems obvious that what he’s offering is a potential reduction, abstracting away from the six OED definitions to define a consciousness space of four dimensions. Not the least interesting aspect of this is that it implies the conceptual possibility of unknown forms of consciousness which would be situated in unpopulated regions of the space. Suppose, for example, we have a form of consciousness with high intersubjectivity, but low objectivation, apprehension, and introspection? My imagination begins to fail me, but I think that would be a kind of diffuse but powerful general empathy. I’m surprised this aspect has not been explored.