Reality

knight 4This is the last of four posts about key ideas from my book The Shadow of Consciousness, and possibly the weirdest; this time the subject is reality.

Last time I suggested that qualia – the subjective aspect of experiences that gives them their what-it-is-like quality – are just the particularity, or haecceity, of real experiences. There is something it is like to see that red because you’re really seeing it; you’re not just understanding the theory, which is a cognitive state that doesn’t have any particular phenomenal nature. So we could say qualia are just the reality of experience. No mystery about it after all.

Except of course there is a mystery – what is reality? There’s something oddly arbitrary about reality; some things are real, others are not. That cake on the table in front of me; it could be real as far as you know; or it could indeed be that the cake is a lie. The number 47, though, is quite different; you don’t need to check the table or any location; you don’t need to look for an example, or count to fifty; it couldn’t have been the case that there was no number 47. Things that are real in the sense we need for haecceity seem to depend on events for their reality. I will borrow some terminology from Meinong and call that dependent or contingent kind of reality existence, while what the number 47 has got is subsistence.

What is existence, then? Things that exist depend on events, I suggested; if I made a cake and put it in the table, it exists; if no-one did that, it doesn’t. Real things are part of a matrix of cause and effect, a matrix we could call history. Everything real has to have causes and effects. We can prove that perhaps, by considering the cake’s continuing existence. It exists now because it existed a moment ago; if it had no causal effects, it wouldn’t be able to cause its own future reality, and it wouldn’t be here. If it wasn’t here, then it couldn’t have had preceding causes, so it didn’t exist in the past either. Ergo, things without causal effects don’t exist.

Now that’s interesting because of course, one of the difficult things about qualia is that they apparently can’t have causal effects. If so, I seem to have accidentally proved that they don’t exist! I think things get unavoidably complex here. What I think is going on is that qualia in general, the having of a subjective side, is bestowed on things by being real, and that reality means causal efficacy. However, particular qualia are determined by the objective physical aspects of things; and it’s those that give specific causal powers. It looks to us as if qualia have no causal effects because all the particular causal powers have been accounted for in the objective physical account. There seems to be no role for qualia. What we miss is that without reality nothing has causal powers at all.

Let’s digress slightly to consider yet again my zombie twin. He’s exactly like me, except that he has no qualia, and that is supposed to show that qualia are over and above the account given by physics. Now according to me that is actually not possible, because if my zombie twin is real, and physically just the same, he must end up with the same qualia. However, if we doubt this possibility, David Chalmers and others invite us at least to accept that he is conceivable. Now we might feel that whether we can or can’t conceive of a thing is a poor indicator of anything, but leaving that aside I think the invitation to consider the zombie twin’s conceivability draws us towards thinking of a conceptual twin rather than a real one. Conceptual twins – imaginary, counterfactual, or non-existent ones – merely subsist; they are not real and so the issue of qualia does not arise. The fact that imaginary twins lack qualia doesn’t prove what it was meant to; properly understood it just shows that qualia are an aspect of real experience.

Anyway, are we comfortable with the idea of reality? Not really, because the buzzing complexity and arbitrariness of real things seems to demand an explanation. If I’m right about all real things necessarily being part of a causal matrix, they are in the end all part of one vast entity whose curious firm should somehow be explicable.

Alas, it isn’t. We have two ways of explaining things. One is pure reason: we might be able to deduce the real world from first principles and show that it is logically necessary. Unfortunately pure reason alone is very bad at giving us details of reality; it deals only with Platonic, theoretical entities which subsist but do not exist. To tell us anything about reality it must at least be given a few real facts to work on; but when we’re trying to account for reality as a whole that’s just what we can’t provide.

The other kind of explanation we can give is empirical; we can research reality itself scientifically and draw conclusions. But empirical explanations operate only within the causal matrix; they explain one state of affairs in terms of another, usually earlier one. It’s not possible to account for reality itself this way.

It looks then, as if reality is doomed to remain at least somewhat mysterious, unless we somehow find a third way, neither empirical nor rational.

A rather downbeat note to end on, but sincere thanks to all those who have helped make the discussion so interesting so far…

Haecceity

knight 3This is the third in a series of four posts about key ideas from my book The Shadow of Consciousness; this one is about haecceity, or to coin a plainer term, thisness. There are strong links with the subject of the final post, which will be that ultimate mystery, reality.

Haecceity is my explanation for the oddity of subjective experience. A whole set of strange stories are supposed to persuade us that there is something in subjective experience which is inexpressible, outside of physics, and yet utterly vivid and undeniable. It’s about my inward experience of blue, which I can never prove is the same as yours; about what it is like to see red.

One of the best known thought experiments on this topic is the story of Mary the Colour Scientist. She has never seen colour, but knows everything there is to know about colour vision; when she sees a red rose for the first time, does she come to know something new? The presumed answer is yes: she now knows what it is like to see red things.

Another celebrated case asks whether I could have a ‘zombie’ twin, identical to me in every physical respect, who did not have these purely subjective aspects of experience – which are known as ‘qualia’, by the way. We’re allowed to be unsure whether zombie twin is possible, but expected to agree that he is at least conceivable; and that that’s enough to establish that there really is something extra going on, over and above the physics.

Most people, I think, accept that qualia do exist and do raise a problem, though some sceptics denounce the entire topic as more or less irretrievable nonsense. Qualia are certainly very odd; they have no causal effects, so nothing we say about them was caused by them: and they cannot be directly described. What we invariably have to do is refer to them by an objective counterpart: so we speak of the quale of hearing middle C, though middle C is in itself an irreproachably physical, describable thing (identifying the precisely correct physical counterpart for colour vision is actually rather complex, though I don’t think anyone denies that you can give a full physical account of colour vision).

I suggest we can draw two tentative conclusions about qualia. First, knowledge of qualia is like knowledge of riding a bike: it cannot be transferred in words. I can talk until I’m blue in the face about bike riding, and it may help a little, but in the end to get that knowledge you have to get on a bike. That’s because for bike riding it’s your muscles and some non-talking parts of your brain that need to learn about it; it’s a skill. We can’t say the same about qualia because experiencing them is not a skill we need to learn; but there is perhaps a common factor; you have to have really done it, you have to have been there.

Second, we cannot say anything about qualia except through their objective counterparts. This leaves a mystery about how many qualia there are. Is there a quale of scarlet and a quale of crimson? An indefinite number of red qualia? We can’t say, and since all hypotheses about the number of qualia are equally good, we ought to choose the least expensive under the terms of Occam’s Razor; the one with the fewest entities. It would follow from that that there is really only one universal quale; it provides the vivid liveliness while the objective aspects of the experience provide all the content.

So we have two provisional conclusions: all qualia are really the same thing conditioned differently by the objective features of the experience; and to know qualia you have to have ‘been there’, to have had real experience. I think it follows naturally from these two premises that qualia simply represent the particularity of experience; its haecceity. The aspect of experience which is not accounted for by any theory, including the theories of physics, is simply the actuality of experience. This is no discredit to theory: it is by definition about the general and the abstract and cannot possibly include the particular reality of any specific experience.

Does this help us with those two famous thought experiments? In Mary’s case it suggests that what she knows after seeing the rose is simply what a particular experience is like. That could never have been conveyed by theoretical knowledge. In the case of my zombie twin, the real turning point is when we’re asked to think whether he is conceivable; that transfers discussion to a conceptual, theoretical plane on which it is natural to suppose nothing has particularity.

Finally, I think this view explains why qualia are ineffable, why we can’t say anything directly about them. All speech is, as it were, second order: it’s about experiences, not the described experience itself. When we think of any objective aspect, we summon up the appropriate concepts and put them over in words; but when we attempt to convey the haecceity of an experience it drops out as soon as we move to a conceptual level. Description, for once, cannot capture what we want to convey.

There’s nothing in all this that suggests anything wrong or incomplete about physics; no need for any dualism or magic realm. In a lot of ways this is simply the sceptical case approached more cautiously and from a different angle. It does leave us with some mystery though: what is it for something to be particular; what is the nature of particularity? We’ve already said we can’t describe it effectively or reduce it theoretically, but surely there must be something we can do to apprehend it better? This is the problem of reality…

[Many thanks to Sergio for the kind review here. Many thanks also to the generous people who have given me good reviews on amazon.com; much appreciated!]

Pointing

knight 2This is the second of four posts about key ideas from my book The Shadow of Consciousness. This one looks at how the brain points at things, and how that could provide a basis for handling intentionality, meaning and relevance.

Intentionality is the quality of being about things, possessed by our thoughts, desires, beliefs and (clue’s in the name) our intentions. In a slightly different way intentionality is also a property of books, symbols, signs and, pointers. There are many theories out there about how it works; most, in my view, have some appeal, but none looks like the full story.

Several of the existing theories touch on a handy notion of natural meaning proposed by H.P.Grice. Natural meaning is essentially just the noticeable implication of things. Those spots mean measles; those massed dark clouds mean rain. If we regard this kind of ‘meaning’ as the wild, undeveloped form of intentionality we might be able to go on to suggest how the full-blown kind might be built out of it; how we get to non-natural meaning, the kind we generally use to communicate with and the kind most important to consciousness.

My proposal is that we regard natural meaning as a kind of pointing, and that pointing, in turn, is the recognition of a higher-level entity that links the pointer with the target. Seeing dark clouds and feeling raindrops on your head are two parts of the recognisable over-arching entity of a rain-storm. Spots are just part of the larger entity of measles. So our basic ability to deal with meanings is simply a consequence of our ability to recognise things at different levels.

Looking at it that way, it’s easy enough to see how we could build derived intentionality, the sort that words and symbols have; the difference is just that the higher-level entities we need to link everything up are artificial, supplied by convention or shared understanding: the words of a language, the conventions of a map. Clouds and water on my head are linked by the natural phenomenon of rain: the word ‘rain’ and water on my head are linked by the prodigious vocabulary table of the language. We can imagine how such conventions might grow up through something akin to a game of charades; I use a truncated version of a digging gesture to invite my neighbour to help with a hole: he gets it because he recognises that my hand movements could be part of the larger entity of digging. After a while the grunt I usually do at the same time becomes enough to convey the notion of digging.

External communication is useful, but this faculty of recognising wholes for parts and parts for wholes enables me to support more ambitious cognitive processes too, and make a bid for the original (aka ‘intrinsic’) intentionality that characterises my own thoughts, desires and beliefs. I start off with simple behaviour patterns in which recognising an object stimulates the appropriate behaviour; now I can put together much more complex stuff. I recognise an apple; but instead of just eating it, I recognise the higher entity of an apple tree; from there I recognise the long cycle of tree growth, then the early part in which a seed hits the ground; and from there I recognise that the apple in my hand could yield the pips required, which are recognisably part of a planting operation I could undertake myself…

So I am able to respond, not just to immediate stimuli, but to think about future apples that don’t even exist yet and shape my behaviour towards them. Plans that come out of this kind of process can properly be called intentional (I thought about what I was doing) and the fact that they seem to start with my thoughts, not simply with external stimuli, is what justifies our sense of responsibility and free will. In my example there’s still an external apple that starts the chain of thought, but I could have been ruminating for hours and the actions that result might have no simple relationship to any recent external stimulus.

We can move thinks up another notch if I begin, as it were, to grunt internally. From the digging grunt and similar easy starts, I can put together a reasonable kind of language which not only works on my friends, but on me if I silently recognise the digging grunt and use it to pose to myself the concept of excavation.

There’s more. In effect, when I think, I am moving through the forest of hierarchical relationships subserved by recognition. This forest has an interesting property. Although it is disorderly and extremely complex, it automatically arranges things so that things I perceive as connected in any way are indeed linked. This means it serves me as a kind of relevance space, where the things I may need to think about are naturally grouped and linked. This helps explain how the human brain is so good at dealing with the inexhaustible: it naturally (not infallibly) tends to keep the most salient things close.

In the end then, human style thought and human style consciousness (or at any rate the Easy Problem kind) seem to be a large and remarkably effective re-purposing of our basic faculty of recognition. By moving from parts to whole to other parts and then to other wholes, I can move through a conceptual space in a uniquely detached but effective way.

That’s a very compressed version of thoughts that probably need a more gentle introduction, but I hope it makes some sense. On to haecceity!

 

Inexhaustibility

knight 1This is the first of four posts about key ideas from my book The Shadow of Consciousness. We start with the so-called Easy Problem, about how the human mind does its problem-solving, organism-guiding thing. If robots have Artificial Intelligence, we might call this the problem of Natural Intelligence.

I suggest that the real difficulty here is with what I call inexhaustible problems – a family of issues which includes non-computability, but goes much wider. For the moment all I aim to do is establish that this is a meaningful group of problems and just suggest what the answer might be.

It’s one of the ironies of the artificial intelligence project that Alan Turing both raised the flag for the charge and also set up one of the most serious obstacles. He declared that by the end of the twentieth century we should be able to speak of machines thinking without expecting to be contradicted; but he had already established, in his solution to the Halting Problem, that certain questions are unanswerable by the Universal Turing Machine and hence by the computers that approximate it. The human mind, though, is able to deal with these problems: so he seemed to have identified a wide gulf separating the human and computational performances he thought would come to be indistinguishable.

Turing himself said it was, in effect, merely an article of faith that the human mind did not ultimately, in respect of some problems, suffer the same kind of limitations as a computer; no-one had offered to prove it.

Non-computability, at any rate, was found to arise for a large set of problems; another classic example being the Tiling Problem. This relates to sets of tiles whose edges match, or fail to match, rather like dominoes. We can imagine that the tiles are square, with each edge a different colour, and that the rule is that wherever two edges meet, they must be the same colour. Certain sets of tiles will fit together in such a way that they will tile the plane: cover an infinite flat surface: others won’t – after a while it becomes impossible to place another tile that matches. The problem is to determine whether any given set will tile the plane or not. This turns out unexpectedly to be a problem computers cannot answer. For certain sets of tiles, an algorithmic approach works fine; those that fail to tile the plain quite rapidly, and those that do so by forming repeating patterns like wallpaper. The fly in the ointment is that some elegant sets of tiles will cover the plane indefinitely, but only in a non-repeating, aperiodic way; when confronted with these, computational processes run on forever, unable to establish that the pattern will never begin repeating. Human beings, by resorting to other kinds of reasoning, can determine that these sets do indeed tile the plane.

Roger Penrose, who designed some examples of these aperiodic sets of tiles, also took up the implicit challenge thrown down by Turing, by attempting to prove that human thought is not affected by the limitations of computation. Penrose offered a proof that human mathematicians are not using a knowably sound algorithm to reach their conclusions. He did this by providing a cunningly self-referential proposition stated in an arbitrary formal algebraic system; it can be shown that the proposition cannot be proved within the system, but it is also the case that human beings can see that in fact it must be true. Since all computers are running formal systems, they must be affected by this limitation, whereas human beings could perform the same extra-systemic reasoning whatever formal system was being used – so they cannot be affected in the same way.

Besides the fact that the human mind is not restricted to a formal system, Penrose established that it out-performs the machine by looking at meanings; the proposition in his proof is seen to be true because of what it says, not because of its formal syntactical properties.

Why is it that machines fail on these challenges, and how? In all these cases of non-computability the problem is that the machines start on processes which continue forever. The Turing Machine never halts, the tiling patterns never stop getting bigger – and indeed, in Penrose’s proof the list of potential proofs which has to examined is similarly infinite. I think this rigorous kind of non-computability provides the sharpest, hardest-edged examples of a wider and vaguer family of problems arising from inexhaustibility.

A notable example of inexhaustibility in the wider sense is the Frame Problem, or at least its broader, philosophical version. In Dennett’s classic exposition, a robot fails to notice an important fact; the trolley that carries its spare battery also bears a bomb. Pulling out the trolley has fatal consequences. The second version of the robot looks for things that might interfere with its safely regaining the battery, but is paralysed by the attempt to consider every logically possible deduction about the consequences of moving the trolley. A third robot is designed to identify only relevant events, but is equally paralysed by the task of considering the relevance of every possible deduction.

This problem is not so sharply defined as the Halting Problem or the Tiling Problem, but I think it’s clear that there is some resemblance; here again computation fails when faced with an inexhaustible range of items. Combinatorial explosion is often invoked in these cases – the idea that when you begin looking at permutations of elements the number of combinations rises exponentially, too rapidly to cope with: that’s not wrong, but I think the difficulty is deeper and arises earlier. Never mind combinations: even the initial range of possible elements for the AI to consider is already indefinably large.

Inexhaustible problems are not confined to AI. I think another example is Quine’s indeterminacy of translation. Quine considered the challenge of interpreting an unknown language by relating the words used to the circumstances in which they were uttered. Roughly speaking, if the word “rabbit” is used exactly when a rabbit is visible, that’s what it must mean; and through a series of observations we can learn the whole language. Unfortunately, it turns out that there is always an endless series of other things which the speaker might mean. Common sense easily rejects most of them – who on earth would talk about “sets of undetached rabbit parts”? – but what is the rigorous method that explains and justifies the conclusions that common sense reaches so easily? I said this was not an AI problem, but in a way it feels like one; arguably Quine was looking for the kind of method that could be turned into an algorithm.

In this case, we have another clue to what is going on with inexhaustible problems, albeit one which itself leads to a further problem. Quine assumed that the understanding of language was essentially a matter of decoding; we take the symbols and decode the meaning, process the meaning and recode the result into a new set of symbols. We know now that it doesn’t really work like that: human language rests very heavily on something quite different; the pragmatic reading of implicatures. We are able to understand other people because we assume they are telling us what is most relevant, and that grounds all kinds of conclusions which cannot be decoded from their words alone.

A final example of inexhaustibility requires us to tread in the footsteps of giants; David Hume, the Man Who Woke Kant, discovered a fundamental problem with cause and effect. How can we tell that A causes B? B consistently follows A, but so what? Things often follow other things for a while and then stop. The law of induction allows us to conclude that if B is regularly followed by A, we can conclude that it will go on doing so. But what justifies the law of induction? After all, many potential inductions are obviously false. Until quite recently a reasonable induction told us that Presidents of the United States were always white men.

Dennett pointed out that, although they are not the same, the Frame Problem and Hume’s problem have a similar feel. They appear quite insoluble, yet ordinary human thought deals with them so easily it’s sometimes hard to believe the problems are real. It’s hard to escape the conclusion that the human mind has a faculty which deals with inexhaustible problems by some non-computational means. Over and over again we find that the human approach to these problems depends on a grasp of relevance or meaning; no algorithmic approach to either has been found.

So I think we need to recognise that this wider class of inexhaustible problem exists and has some common features. Common features suggest there might be a common solution, but what is it? Cutting to the chase, I think that in essence the special human faculty which lets us handle these problems so readily is simply recognition. Recognition is the ability to respond to entities in the world, and the ability to recognise larger entities as well as smaller ones within them opens the way to ‘seeing where things are going’ in a way that lets us deal with inexhaustible problems.

As I suggested recently, recognition is necessarily non-algorithmic. To apply rules, we need to have in mind the entities to which the rules apply. Unless these are just given, they have to be recognised. If recognition itself worked on the basis of rules, it would require us to identify a lower set of entities first – which again, could only be done by recognition, and so on indefinitely.

In our intellectual tradition, an informal basis like this feels unsatisfying, because we want proofs; we want something like Euclid, or like an Aristotelian syllogism. Hume took it that cause and effect could only be justified by either induction or deduction; what he really needed was recognition: recognition of the underlying entity of which both cause and effect are part. When we see that B is the result of A, we are really recognising that B is A a little later and transformed according to the laws of nature. Indeed, I’d argue that sometimes there is no transformation: the table sitting quietly over there is the cause of its own existence a few moments later.

As a matter of fact I claim that while induction relies directly on recognising underlying entities, even logical deduction is actually dependent on seeing the essential identity, under the laws of logic, of two propositions.

Maybe you’re provisionally willing to entertain the idea that recognition might work as a basis  for induction, sort of.  But how, you ask, does recognition deal with all the other problems? I said that inexhaustible problems call for mastery of meaning and relevance: how does recognition account for those? I’ll try to answer that in part 2.