Consciousness as a target for the artificial sciences

1. Consciousness as a target for the artificial sciences Steve Torrance March 2007

2. Consciousness as a target for the artificial sciences. The topic of this talk is: The realizability of Artificial Consciousness. The basic message is: It’s a long way off. No surprise there, perhaps. Except that some tenaciously beg to differ and see it as imminent. The point of the discussion is that dealing with the question in proper depth helps us to get a better grip both on the nature of (actual and possible) consciousness and on the scope and limits of ‘the sciences of the artificial’. I’ll make three distinctions. First, between ‘strong’ and ‘weak’ artificial consciousness (AC). It’s mainly the strong AC project that I’ll be considering here. (Actually AC researchers are rather coy about whether they’re pursuing the first, the second, or both.) Second, between ‘thin’ and ‘thick’ conceptions of consciousness. I’ll argue that an inadequate, ‘thin’ conception of consciousness dominates the thought of many devotees of AC, as well as the thought of defenders of traditional (anti-physicalist or anti-computational) approaches to consciousness and mind. Third, there’s the distinction between ‘functional’ and ‘phenomenal’ consciousness. Many AC workers see the former as a kind of ‘half-way house’ to realizing strong AC. I’ll argue that you can’t have functional consciousness alone. When we talk about functional consciousness we’re talking about the functional aspects of a (phenomenally) conscious organism. On the ‘thick’ conception of consciousness, there are perhaps different ways to elaborate this. I’ll sketch one approach. This consists in seeing consciousness in terms of a kind of ‘Grand Inventory’ of miscellaneous strands. All or most of these have to be addressed head-on in any serious AC research plan. This gives mixed news. Strong AC is a long way further off (and may require as yet undreamt-of technological platforms). But at least we will have a more realistic set of success-criteria for the enterprise. This probably has general implications for how we view the past and future of ‘the sciences of the artificial’. And we will also have learned more about the nature of natural consciousness.

3. Background • Background to this talk • Workshop on ethics and artificial agents, Baden-Baden, 2004 • AISB Workshops on Machine Consciousness, Hertfordshire, 2005; Bristol, 2006 • Forthcoming special issue on Machine Consciousness (edited with Ron Chrisley and Rob Clowes), Journal of Consciousness Studies, July 2007. • The topic: the realizability of Artificial Consciousness • The message: it’s a long way off • The point: dealing with the question in proper depth helps us to get a better grasp on • the nature of (actual and possible) consciousness • the scope and limits of the sciences of the artificial

4. Artificial Consciousness as a project My concern in this talk is about THE PROJECT OF DEVELOPING ARTIFICIAL CONSCIOUSNESS (AC) A central question is: What features of the natural phenomenon of consciousness need to be taken seriously by workers in ‘the sciences of the artificial’ working on building (AC) systems? I propose to draw up a Grand Inventory of such features, as a guide for those intent on creating AC. This is dependent on a certain conception of consciousness that I call the ‘thick’ (or deep) conception (as opposed to the ‘thin’ (or shallow) one) Much of the discussion will be on the necessary preliminary philosophical issues

5. Three distinctions • Weak versus strong Artificial Consciousness (AC) • Thin versus thick conceptions of C and AC • Functional versus phenomenal consciousness

6. Two kinds of research into Artificial Consciousness ‘WEAK AC’ Corresponds to ‘weak AI’; ‘weak ALife’… Trying to produce systems that clarify aspects of biological consciousness,… but without any pretension to be producing actual consciousness in artificial form Ontologically innocent i.e. doesn’t make claims about the conditions for the existence of consciousness in artificial systems ‘STRONG AC’ Cf ‘strong AI’; ‘strong ALife’… Aiming to generate actual (psychologically real) consciousness artificially At the moment only computationally-based platforms are used – … one day perhaps artificial biology / neuro-engineering? Ontologically loaded i.e. it DOES make claims about conditions for the existence of consciousness in artificial systems

7. The distinction between ‘thin’ and ‘thick’ conceptions of consciousness • Alongside ‘weak’ and ‘strong’ AC it is possible to put another distinction • Between ‘thin’ (shallow) conceptions of consciousness • And ‘thick’ (deep) conceptions • This is a distinction between conceptions of consciousness per se, not (just) artificial forms of C. • I’ll claim that most current approaches to strong AC (and maybe weak AC too) rest on a ‘thin’ conception • … and that ‘thin’ conceptions do not provide an adequate understanding of what consciousness is • To do this, we need to delve into a little of the background of standard debates on consciousness by certain philosophers (Frank Jackson, David Chalmers, etc.)

8. Computationalism, Physicalism and the anti-physicalist thought-experiments. Scientists like to assume that the physical world (including brains, bodies, etc.) IS ALL THERE IS. So consciousness must have a FULLY PHYSICAL EXPLANATION – it must be explained totally in terms of physical processes in the brain & body, and their interactions with the physical world. (Physicalism) Computer scientists often assume, in addition, that the brain is a kind of (complex) computer. and that consciousness can be explained in terms of computational processes realized in the physical brain. (Computationalism) The strong AI and AC programs are based on the assumptions that physicalism and computationalism are both true. (Maybe weak AI/AC too) BUT: There are a variety of arguments which aim to disprove physicalism Such arguments are often based on ‘thought-experiments’ – descriptions of scenarios that are empirically impossible but conceptually possible.

9. Two anti-physicalist thought-experients TE1 Color-blind brain science. (Jackson) A person can know all there is to know about the physical explanation of color experience (e.g. in terms of brain processes) … and yet have never seen colors or had color experience (e.g. by being congenitally color-blind). So (it’s argued) there’s something else to experience over and above the physical features. TE2 Zombie-worlds. (Chalmers) If the physical features of brains, etc. fully explained experience, … then it wouldn’t be even conceivable that you could have a world physically identical to ours but without any experience. But (it’s argued) such a world (A Zombie World) is at least conceptually conceivable. So consciousness must be something ontologicallyover and above the physical

10. Response to the anti-physicalist thought-experiments I wish to propose that All such arguments and thought experiments depend on a certain conception of what consciousness is –the ‘thin’ (or shallow) conception There is an alternative, more adequate conception – the ‘thick’ (or deep) conception. The thin conception rightly emphasizes the phenomenal ‘feel’ of consciousness. But it does so at the expense of any other aspect of consciousness On the thin conception, the notion of conscious or phenomenal feel is conceptually divorcible from any other features in an agent, including all cognitive processes, behaviour, brain functioning, body-system activity, etc. The thin conception tends to lead to a dualist or epiphenomenalist view On the thick conception, consciousness is seen in terms of the real, physical characteristics of embodied beings who experience conscious subjectivity, as well as in terms of the subjective feeling itself.

11. More on the thick and thin conceptions On the thick conception, consciousness is, CONCEPTUALLY, a complex, multidimensional natural, biological, physically embodied, process of which phenomenal feel is just one part (but an important part) The anti-physicalist thought- experiments gain their persuasive force from the thin conception The thought-experiments seem harder to launch successfully on the thick conception -- So the threat of a dualist or anti-physicalist conclusion is avoided A world of zombies which are physically like us but which lack phenomenal consciousness … seems a confusing idea if consciousness is an essentially embodied and biological process; The idea of a color-scientist who knows all the physical facts about consciousness but is unaware of what it’s like to see red … seems puzzling if the experience of seeing red is CONCEPTUALLY bound up with physiological processes that underpin that experience

12. Functional vs phenomenal consciousness • Cf: ‘Two Conceptions of Machine Phenomenality’ – forthcoming in special issue of Journal of Consciousness Studies • (In this paper I apply the thin/thick distinction directly to the domain of Machine Consciousness) • How does the thin/thick division relate to debates over artificial or machine C? • In order to see this we need to discuss a third distinction – between ‘phenomenal’ and ‘functional’ consciousness

13. Artificial consciousness researchers tend to ‘cognitivize’ or ‘functionalize’ consciousness When AC researchers talk about consciousness, they tend to talk in terms of ‘functional’ or ‘cognitive’ or ‘access’ consciousness, rather than ‘phenomenal’ or ‘qualitative’ consciousness. This idea refers to the cognitive roles that consciousness appears to perform in our mental lives. E.g.: according to Bernard Baars’ Global Workspace (GW) theory, consciousness’s role is explained in terms of its contribution to the functional architecture of our cognitive processing GW Theory: Consciousness works as a central ‘message-board’ which allows information to be passed to the various non-conscious functional agencies which are operating in parallel Thus: According to GW theory, C subserves the performance of non-routine tasks, such as driving round a narrow mountain pass; working out a difficult mathematical calculation using imaginative rehearsal to plan a motor action.

14. The uses of cognitive conceptions of consciousness It’s fine to be talking about cognitive or functional aspects of consciousness if one has no pretensions to be doing ‘strong AC’ i.e. to be building a truly conscious machine, system or artificial creature But often people talk as if they are really interested in developing a machine which (a) really is conscious, but (b) is only functionally conscious Such people often then go on to state one of two things: one day, through further developments along similar lines, phenomenal consciousness may possibly develop – because all that phenomenal consciousness can be, is very complex and subtle functionalities OR: phenomenal consciousness is just a myth or a muddle

15. How AC researchers deal with phenomenal consciousness AC researchers tend to feel awkward about phenomenal consciousness. Getting too fixated on the phenomenal feel of consciousness seems to make AC a doomed project. (It’s much easier to see how computers can replicate the cognitive, intelligent aspects of mind, than the feeling, phenomenal aspects.) So… AC researchers adopt various strategies to cope with the fact that phenomenal feel is hard to fit into a computational framework. Here are some: The eliminativist strategy ‘Qualia’, phenomenal C, etc are illusory, confused notions.. 2. The functionalist strategy Phenomenal C can be subsumed under functional or cognitive C. 3. The agnostic strategy We’ll never know enough about phenomenal C so let’s just concentrate on functional C 4. The special pleading strategy Artificial, computationally-based C would be special kind of consciousness, so not directly comparable to biological C.

16. So: Computationalists also trade on the thin conception All of these strategies tend in different ways to downgrade or marginalise phenomenal consciousness PLUS: The computationalist strategies also tend to trade on the thin conception of C. Eliminativists rightly question phenomenality ‘thinly’ conceived Cognitivists are right to believe that there is a close connection between phenomenal feel and cognitive or functional features (such as global workspace, etc) And computationalists are rightly impatient with the arguments offered against physicalism. BUT: computationalists are operating with their own version of the thin conception: They take the thin conception for granted – by assuming that it is the only way phenomenal feel can be understood And in fact operating with the thin conception allows phenomenality to be more easily ‘reduced away’ or eliminated So in a certain way opponents of physicalism and their computationalist critics feed out of each others’ pockets.

17. Illustration: Stan Franklin’s IDA Stan Franklin’s IDA program is an expert system running on a (desktop) computer, - which assigns postings to US Navy personnel Franklin designed it using Baars’ Global Workspace theory as a model Franklin claims that it has functional, but not phenomenal, consciousness. Many other AC models use GW theory, or other cognitive/functional models of consciousness BUT: Is functionalconsciousness, consciousness?

18. ‘The billion dollar challenge’ (Bringsjord) Selmer Bringsjord (JCS, forthcoming) imagines being offered $1bn to develop a phenomenally conscious artificial being Are there any circumstances in which it would be prudent, or indeed morally acceptable, to accept the challenge? This is clearly a ‘strong AC’ project Producing ‘merely’ functional consciousness wouldn’t suffice to gain the $1bn. But could one produce a ‘functionally’ conscious artifical being (which one wasn’t claiming to be phenomenally conscious) as a kind of half-way house to ‘strong AC’? (¢1 bn challenge?)

19. The idea of functional consciousness as a half-way house Could you be claiming to have produced ‘real’ consciousness if all you could claim to have produced was ‘functional’ consciousness That is – if all you had was a device that produced all the cognitive aspects of consciousness without the phenomenal ‘feel’? Argument against this: Functional consciousness is not a separate form of consciousness which is an optional extra to ‘full’ phenomenal consciousness, but the functional aspects of the integral phenomenon of consciousness… i.e. the functionality of a conscious being

20. If you have simply reproduced the functionality, you have a non-conscious system which functions in the way a conscious system would = that’s all • That is: it’s NOT the case that … (a) there are two different ways in which a system can be conscious • functional; phenomenal (or both) NOR is it the case that … (b) You can have a system that is conscious in functional way independently of its being conscious in the phenomenal way. • So the idea of targeting ‘functional consciousness’ as a half-way house to strong AC doesn’t work • Not even worth 10 cents…

22. A wrong way to put the objection to the half-way house proposal HOWEVER: There’s a WRONG way to put the objection to the ‘half-way house’ proposal This would be to say… ‘All that a so-called ‘functionally conscious’ system could do is produce the OUTER accompaniments to C, rather than the INNER feel’ To talk about phenomenal consciousness as inner feel is to be as much in the grip of the thin conception as conventional AC research… The ‘thin’ conception is the idea that phenomenality must be some special property, which can be peeled away from all external or observable processes We have to find an alternative to this idea..

23. The thick conception of consciousness – one version Phenomenal consciousness is real and non-illusory, And it has to be central to any self-respecting AC project. But it has to be reconceptualized … by adopting a more groundedand conceptually holistic conception of what consciousness is. Phenomenal consciousness is important, but there is more to consciousness than EITHER just phenomenality OR function Consciousness is a rich, complex, multidimensional cluster of disparate features, All (or a significant majority) of these have to be seriously taken into account when attempting to ‘build’ consciousness in the way the strong AC programme wishes to do. The following list is indicative, not definitive…

24. Consciousness as a richly interconnected cluster of features • Phenomenal feel • Cognition/intentional content • Selfhood • Embodiment/organism • Neurophysiology • Architectural/functional aspects • Affect/teleology • Behavior/sensorimotor activity • Environmental coupling • Intersubjective/developmental aspects • Ethics/normativity • Autonomy • . . . . . ? (an open-ended collection?)

25. Towards a Grand Inventory (i) Phenomenal feel (qualia) ‘Qualia’ are the total personal states that we are in whenever we have an experience E.g. pain isn’t just ‘in’ the foot or ‘in’ the brain (or ‘in’ the mind) The phenomenal feel is not ontologically separable from the other features – it’s just how it feels to be in that total personal state (2) Cognition/Intentional content Intentionality: aboutness – e.g. imagining or seeing the Eiffel Tower; Most (all?) phenomenal states are states of something – i.e. they have intentional content (3) Selfhood Self as owner of conscious states A perspectival point of view from which states are experienced Again, there is controversy over whether selfhood is more than a formal notion - (E.g. T. Metzinger: On Being No-one – conscious minds operate with a transparent ‘phenomenal self-model’ – but no real self.) (4) Embodiment/organism Consciousness as an evolved process – how ancient? Relation between having a metabolismper se and ‘inwardness’ (Hans Jonas) The organic-biological nature of all (known) consciousness provides a strong challenge to computational or robotic forms of AC

26. Towards a Grand Inventory (ii) Neurophysiological aspects Clearly, neurophysiological organisation is crucial to known forms of C It’s become fashionable to search for neural correlates of consciousness (F. Crick; ‘You’re nothing but a pack of neurons’) Some devotees of ‘consciousness science’ are saying that NCCs should be fully mapped out in 50 years So AC could provide increasingly fine-grained computational replications of neural organization But will that be sufficient to produce full consciousness? In any case the goal of mapping NCCs may be philosophically problematic Architectural / functional aspects C clearly plays many roles in our information-processing or cognitive functioning, e.g…. attentive direction of effortful tasks; bringing together disparate processes under unified central control; strategic control of language, perception, memory, etc. There’s the question of whether these processes count on their own as a sort of consciousness?

27. Towards a Grand Inventory (iii) (7) Affective/teleological aspects Conscious states matter to their bearers, often to very large degrees. Phenomenology has a positive/negative appraisal valency Consciousness is bound up with goals: only beings with intrinsic teleology have phenomenal consciousness (8) Behavioral/sensorimotor aspects Behavior can’t be divorced (as 3rd person) from consciousness Perceptual consciousness as embodied sensorimotor activity (O’Regan and Noë, Hurley) So the behavioral features of consciousness aren’t just (non-conscious) accompaniments, but part of the totality of how consciousness manifests itself. (9) Environmental aspects Consciousness can’t be properly understood unless we include, beside the ‘inner’ processes the subject’s ‘lived’ world, and the dynamic coupling between subject and world (10) Intersubjective (and developmental) aspects Our own self-awareness is in large part determined by our sense of other selves. The way we feel is dependent upon our grasp of social dynamics (such as shared attention, communicative interaction, ‘theory of mind’, etc) that we learn from infancy Evan Thompson: Empathy(experiencing the awareness of others) is an precondition of consciousness

28. Towards a Grand Inventory (iv) Normative/moral aspects Consciousness is morally critical, as compared to other aspects of mind Discussions of sentience in non-human animals, foetuses, machines, etc. have deep moral implications. So, too, does AC, in contrast to AI to seek to build artificially conscious agents raises moral questions that are not raised by mere artificially cognitive agents So the AC research programme carries a crucial ethical responsibility Autonomy Consciousness is strongly tied up with autonomy – self-constitution, self-direction, etc. Some might say that this is the single most important component of consciousness And the one that is hardest to implement (in a genuine way) within an artificial system… It obviously connects in many important ways with teleology/affect/goals Others? There are probably several other strands which deserve separate mention - Self, evolution, ontogeny, autobiography, culture, communication, spirituality, etc.

29. Summing up: Three distinctions 1. Weak AC versus strong AC This discussion has mainly been about the project of strong AC 2. ‘thin’ versus ‘thick’ conceptions of (phenomenal) C Many proponents of strong AC apply a ‘thin’ conception of C as do defenders of traditional (anti-physicalist, anti-computationalist) approaches to C 3. ‘functional’ versus ‘phenomenal’ C It’s incoherent to claim you have produced the first on its own without the second Progress in understanding C and AC can best be made by exploring a ‘thick’ conception of C We’ve done this here by elaborating C as a collection of many interconnected constitutive strands most of these would need to be seriously addressed in any properly founded ‘strong AC’ project.

30. Summing up: From thin to thick Consciousness, defined ‘thinly’ as ‘just’ the subjective feel (or some other focal key property), is a poor foundation for understanding consciousness philosophically or scientifically. ‘Thin’ consciousness is also a poor starting point for research in artificial consciousness By moving to a ‘thick’ model, AC researchers would have a harder, road ahead, but would be working within a more realistically grounded research framework The phenomenon of ‘consciousness’ will, on the ‘thick’ view, be seen as a diverse network of elements, all richly interconnected one with the other.

31. Summing up: Mixed news This is mixed news for a devotee of strong AC It shows the task to be much morecomplex than is currently thought. It’ll require AC researchers to think of consciousness in a much more biologically-oriented way than they do now [cf Tom Ziemke,’What’s Life got to do with it?’ in recent volume on Artificial Consciousness] But because of the strong biological orientation, … it’ll provide a development-path that has clearer criteria of success than methods currently adopted.