… since last two decades, research towards making machines conscious has gained great momentum
Surely not? My perception of the state of play is quite different, at any rate; it seems to me that the optimism and energy which was evident in the quest for machine consciousness twenty or perhaps thirty years ago has gradually ebbed. Not that anyone has really changed their minds on the ultimate feasibility of a conscious artefact, but expectations about when it might be achieved have generally been slipped back further into the future. Effort has been redirected towards related but more tractable problems, ones that typically move us on in useful ways but do not attempt to crack the big challenge in a single bite. You could say that the grand project was in a state of decline, though I think it would be kinder and perhaps more accurate to say it has moved into a period of greater maturity.
That optimistic aside was from Starzyk and Prasad, at the start of their paper A Computational Model of Machine Consciousness in the International Journal of Machine Consciousness. It’s not really fair to describe what they’re offering as GOFAI (Good Old-Fashioned Artificial Intelligence) in the original derogatory sense of the term, but I thought their paper had a definite whiff of the heady optimism of those earlier days.
Notwithstanding that optimism their view is that there are still some bits of foundational work to be done…
there is a lack of a physical description of consciousness that could become a foundation for such models.
…and of course they propose to fill the gap.
They start off with a tip of the hat to five axioms proposed by Aleksander and Dunmall back in 2003 which suggest essential functional properties of a conscious system: embodiment and situatedness, episodic memory, attention, goals and motivation, and emotions. These are said to be necessary but not sufficient conditions for consciousness. If we were in an argumentative mood, I think we could put together a case that some of these are not necessarily essential but we can take it as a useful list for all practical purposes, which is very much where Starzyk and Prasad are coming from.
They give a quick review to some scientific theories (oddly John Searle gets a mention here) and then some philosophical ones. This is avowedly not a comprehensive survey, nor a very lengthy one and the selection is idiosyncratic. Prominent mentions go to Rosenthal’s HOT (Higher Order Theory – roughly the view that a thought is conscious if there is another thought about it) and Baars’ Global Workspace (which must be the most-cited theoretical model by some distance).
In an unexpected and refreshing leap away from the Anglo-Saxon tradition they also cite Nisargadatta, a leading exponent of the Advaita tradition on the distinction between awareness and consciousness. The two words have been recruited to deal with a lot of different distinctions over the years: generally I think ‘awareness’ tends to get used for mere sensory operation or something of that kind which ‘consciousness’ is reserved for something more ruminative. Nisargadatta seems to be on a different tack:
When he uses the term “consciousness”, he seems to equate that term with the knowledge of “I Am”. On the other hand, when he talks about “awareness”, he points to the absolute, something altogether beyond consciousness, which exists non-dualistically irrespective of the presence or absence of consciousness. Thus, according to him, awareness comes first and it exists always. Consciousness can appear and disappear, but awareness always remains.
But then we’re also told:
A plant may be aware of a damage done to it [!], but it cannot be conscious about it, since it is not intelligent. In a similar way a worm cut in half is aware and may even feel the pain but it is not conscious about its own body being destroyed.
To allow awareness to a plant seems like the last extreme of generosity in this area – right at the final point before we tip over into outright panpsychism- but in general these remarks makes it sound more as if we’re dealing with something like the kind of distinction we’re most used to.
Then we have a section on evolution and the development of consciousness, including a table. While I understand that Starzyk and Prasad are keen to situate their account securely in an evolutionary context, it does seem premature to me to discuss the evolution of consciousness before you’ve defined it. In the case of giraffe’s necks, say, there may not be too much of a difficulty, but consciousness is a slippery concept and there is always a danger that you end up discussing something different from, and simpler than, what you first had in mind.
So on to the definition.
…our aim was not to remove ambiguity from philosophers’ discussion about intelligence or various types of intelligence, but to describe mechanisms and the minimum requirements for the machine to be considered intelligent. In a similar effort, we will try to define machine consciousness in functional terms, such that once a machine satisfies this definition, it is conscious, disregarding the level or form of consciousness it may possess.
I felt a slight sense of foreboding at this, but here at last is the definition itself.
A machine is conscious if besides the required mechanisms for perception, action, learning and associative memory, it has a central executive that controls all the processes (conscious or subconscious) of the machine…
…[the] central executive, by relating cognitive experience to internal motivations and plans, creates self-awareness and conscious states of mind.
I’m afraid this too reminds me of the old days when we were routinely presented with accounts that described a possible architecture without ever giving us any explanation of how this particular arrangement of functions gave rise to the magic inner experience of consciousness itself. We ask ourselves: could we put together a machine with a central executive of this kind that wasn’t conscious at all? It’s hard to see why not.
I suppose the central executive idea is why Starzyk and Prasad feel keen on the Global Workspace, though I think it would be wrong to take that as genuinely similar; rather than a central control module, it’s a space where miscellaneous functions can co-operate in an anarchic but productive manner.
Starzyk and Prasad go on to flesh out the model, which consists of three main functional blocks – Sensory-motor, Episodic Memory and Learning, and Central Executive; but none of this helped me with the basic question. There’s also an interesting suggestion that attention switching is analogous to the saccades performed by our eyes. These are instant ballistic movements of the eye’s direction towards things of potential interest (like a flash of light in a dark place); I’m not precisely sure how the analogy works but it seems thought-provoking at least.
They also provide a very handy comparison with a number of other models – a useful section, but it sort of undermines the earlier assertion that there is a gap in this area waiting for attention.
Overall, it turns out that the sense of older times we got at the beginning of the paper is sort of borne out by the conclusion. Many technically inclined people have always been impatient with the philosophical whiffling and keen to get on with building the machine instead, confident that the theoretical insights would bloom from a soil fertilised with practical achievements. But by now we can surely say we’ve tried that, and it didn’t work. Researchers forging ahead without a clear philosophy ran into the frame problem, or simple under-performance, or the inability of their machines to deal with intentionality and meaning. They either abandoned the attempt, adopted more modest goals, or got sidetracked into vast enabling projects such as the compilation of a total encyclopedia to embody background knowledge or the neuronal modelling of an entire brain. In a few cases brute force approaches actually ended up yielding some practical results, but never touched the core issue of consciousness.
I don’t quite know whether it’s sort of depressing that effort is still being devoted to essentially doomed avenues, or sort of heartening that optimism never quite dies.