Archive for April, 2010

Picture: Honeycomb series. Panpsychism, or perhaps it would be more accurate to say panexperientialism, has seemed to be quite a popular view in previous discussions here, but I’ve always found it problematic. Panexperientialism, as the name suggests, is the belief that experience is everywhere; that experience is the basis of reality, out of which everything else is built.  Objects which seem dead and inanimate ultimately consist of experience just as much as we do: it just doesn’t seem like that because the experiences which make them up are not our experiences.  The attractive feature of this view is that it removes some of the mystery from consciousness: instead of being a very rare phenomenon which only occurs in very specific circumstances, such as those which exist in our brains, consciousness of a sort is universal, and so it’ s not at all surprising that we ourselves are conscious.

One of the problems is the question of how many experiential loci we’re dealing with. Does the table have experiences? Does half the table? Do the table legs have four separate sets of experiences, and at the same time a sort of federal joint experience as a composite entity? There are ways to solve these problems, but they’re distinctly off-putting to me. More fundamentally, I’m inclined to doubt whether the theory is as helpful in explaining things as  it seems. OK, so my brain has experience just because it’s an object and all objects have experience; but surely that brain-as-an-object experience is the same kind of thing as the experiences rocks have, while the experience I’m interested in, the kind that influences my bodily behaviour, is something else; something which remains unexplained.

One of the sources of difficulty here, I think, as with many metaphysical theories, is that the philosophical point of view is not well integrated with any clear scientific conception.  When we need to pin down our loci of experience we’re left to rummage around and see what we can come up with – atoms? Too small.  Discrete physical entities? What exactly are they? (Shintoism, if I understand it correctly, has bitten this kind of bullet and given up on a sharp definition of what is animate: lots of things can have souls, but only if they’re salient or impressive. Mount Fuji definitely gets one, but some anonymous pile of dirt in your back garden is just a pile of dirt.)

But what about Finite Eventism? This theory (as expounded by Carey R. Carlson in Chapter 12 of Mind that abides: Panpsychism in the New Millennium) is a theory of physics first and foremost, one that happens to provide a neat basis for a solution to the mind-body problem taking a panpsychist/panexperientialist view. It is based on the late ideas of Russell and Whitehead, though one of its appealing features is that it dovetails well with quantum theory in a way Russell and Whitehead were not aware of.

The gist of the theory is a radical reduction of physics to a minimalist ontology consisting of events and the basic temporal relations of being earlier or later (there’s also cause and effect, which I take to be causally connected varieties of earlier/later). There are some rules which prevent inconsistency (events can’t be earlier/later than themselves) and that’s it. In particular, there is no initial concept of space or extension. We are allowed convergent and divergent causal paths, so we can construct complex multiple ‘honeycomb’ pathways like the one shown. The four consistent axes which appear in these diagrams are taken to make up a 4-D manifold of space-time, with neutrinos and electrons delineated by gaps, and the repetition of patterns in sequence representing persistence over time.  Quanta, in this theory, are represented by the steps between two events; the number of intermediate steps between two events corresponds with the relative frequency of the relevant path, and these relative frequency ratios provide relative energy ratios, following Planck’s E=hf.

I hope those brief,  inadequate remarks give a hint of how the basics of physics can be built up in a very elegant manner from the simple topology of these sequences: it looks impressive, though I must frankly admit that I’m not competent to explain the theory properly, never mind evaluate it. Readers may like to look at this short description (pdf).

The question for us is, what are these ‘events’? Carlson follows Whitehead in seeing them all as ‘occasions of experience’; in some ways they resemble the monads of Leibniz’s radically relativist ontology;  they are pure phenomenal moments. Carlson argues that the basis of all science is phenomenal experience; historically, in order to account for those experiences better through Newtonian style physics it became necessary to postulate unexperienced abstract entities; and then the phenomenal experience dropped out of the theory leaving us with a world made of fundamentally unaccountable entities.

The best part of it for me is that the theory provides relatively good and clear answers to the problems I mentioned above. It’s clear that the loci of experience are situated in the events: I take it that continuity of experience is guaranteed in exactly the same way as physical continuity by repeating patterns (though what the nature of those patterns amounts to is an interesting question).  If that’s so, then the relationship between the consciousness of my brain-as-object and the consciousness of my brain-as-brain is also helpfully clarified.

How far, though, is the actual nature of my consciousness clarified? The explanation of most of my mental characteristics is deferred upwards to be explained by the working of the brain. That is, no doubt, exactly as it should be: but it leaves me with no particular reason to adopt panpsychism. The one feature which the theory does explain is phenomenal experience (alright, a fairly important feature!); but it really only does so by telling us that things just do have phenomenal experience.  Why should we take it that the events are phenomenal in nature – doesn’t ontological parsimony suggest they should be featureless blips?

Still, I think this is the most viable and attractive formulation of panpsychism/panexperientialism I’ve seen.

Picture: Macaque. Can monkeys have blindsight? Sean Allen-Hermanson defends the idea in a recent JCS paper. Blindsight is one of those remarkable phenomena that ought to be a key to understanding conscious perception; but somehow we can never quite manage to agree how the key should be turned.  Blindsight, to put it very briefly, is where subjects with certain kinds of brain lesions deny seeing something, but can reliably point to it when prompted to try. It’s as though the speaking, self-conscious part of the brain is blind, but some other part, well capable of directing the hand when given a chance, can see as well as ever.

There are a number of ways we might account for blindsight. One of the simplest is to suppose that the visual system is degraded but not destroyed in these cases; the signals from the eye are still getting through, but in some way at reduced power. This reduced power level puts them below the limit required for entry into conscious awareness, but they are still sufficient to bias the subject towards the correct response when they are prompted to guess or have a random try. Another popular theory suggests that the effect arises because there are two separate visual channels, only one of which is knocked out in blindsight. There is a good neurological story which can be told in support of this theory, which weighs strongly in its favour;  against it, there have been reports of analogous phenomena in the case of other senses, where it is harder to sustain the idea of physically separate channels. Allen-Hermanson cites claims for touch, smell and hearing (I’ve wondered in the past whether the celebrated deaf percussionist Evelyn Glennie might be an example of “deafhearing”); and even suggestions that the case of alexithymia, in which things not consciously perceived nevertheless cause anxiety or fear, might be similar.  It’s possible, of course, that blindsight itself comes in more than one form with more than one kind of cause, and that there is something in both these theories – which unfortunately would make matters all the more difficult to elucidate.

For those of us whose main interest in is consciousness, blindsight holds out the tantalising possibility of an experimental route into the mystery of qualia, of what it is for there to be a way something looks.  It’s tempting to suppose that what is missing in blindsight patients is indeed phenomenal experience. Like the much-discussed zombies, they receive the data from their senses and are able to act on it, but have no actual experience.  So if we can work out how blindsight works, we’ve naturalised qualia and the hard problem is cracked…

Well, no, of course it isn’t really that easy. The point about qualia, strictly interpreted, is that they don’t cause actions;  qualia-free zombies behave just the same as normal people, and that includes speech behaviour. So the absence of qualia could have no effect on what you say;  since whatever blindsight patients are missing does affect what they say, it can’t be qualia.  Moreover we have no conclusive evidence that blindsight patients have no visual experience; it could be that they have the experience but are simply unable to report it. That might seem a strange state to be in, but patients with brain damage are known to assert or confabulate all sorts of things which are at odds with the evidence of their senses; in fact I believe there are subjects who claim with every sign of sincerity to see perfectly when in fact they are demonstrably blind, which is a nice reversal of the blindsight case.

Still, blindsight is a tantalising glimpse of something important about conscious experience, and has all sorts of implications. To pick out one at random, it casts an interesting light on split-brain patients.  In blindsight cases, we can have an apparent disconnect between the knowledge the patient expresses with the voice, and the knowledge expressed with the hand; that’s pretty much what we get in many experiments on split-brain patients (since normally only one hemisphere has use of the vocal apparatus and the other can only express itself by hand movements).  Any claims that split-brain patients are therefore shown to be two different people in a single skull are undercut unless we’re willing to take up the unlikely position that blindsight patients are also split people.

One interesting extension of blindsight research is the apparent discovery by Cowey and Stoerig of the same phenomenon in monkeys. There is an obvious difficulty here, since human blindsight experiments typically rely on the subject to report in words what they can see, something monkeys can’t do. Cowey and Stoerig devised two experiments; in the first the monkeys were trained to touch a screen where a stimulus appeared; all were able to do this without problems. In the second experiment, the stimulus did not always appear on cue; when it did not, the monkeys were required to press a separate button. Normal monkeys could do this without difficulty, but monkeys with lesions thought to be analogous to those causing blindsight now went wrong when the stimulus appeared in their blind spot, hitting the ‘no stimulus’  button. Taking the two experiments together, it was concluded that blindsight was effectively demonstrated; the damaged monkeys who could earlier touch the right part of the screen even when the stimulus was in their blind spot,  later ‘reported’ the same stimulus as absent.

(Readers may wonder about the ethical propriety of damaging the brains of living primates for these experiments; I haven’t read the original papers, but I suppose we must assume that at any rate the experiments had medical as well as merely philosophical value.)

Of course, these experiments differ significantly from those carried out on human subjects, and as Allen-Hermanson reports,  reasonable doubts were subsequently raised in a 2006 paper by Mole and Kelly, who pointed out that relying on two separate experiments, which made differing demands, made the results inconclusive.  In particular, the second task was more complex than the first, and it could plausibly be argued that the result of having to deal with this additional complexity was that the monkeys simply failed to notice in the second experiment the stimulus they had picked up successfully in the first.

Allen-Hermanson’s aim is to rescue Cowey and Stoerig’s conclusions, while acknowledging the validity of the criticisms. He proposes a new experiment: first the monkeys are trained to press a green button if there is a stimulus (no need to point to where it is any more), and a red one if there is none. Then we introduce two different stimuli: Xs and Os. Both the green and red buttons are now divided in two, one side labelled for X, the other for O. If there is a stimulus, the monkeys must now press either green X or green O depending on which appeared: if there is no stimulus, they can press either red button. Allen-Hermanson believes the blindsighted monkeys will consistently press red X correctly if the stimulus is X, even though they are effectively asserting that there is no stimulus.

Maybe. I can’t help feeling that all the monkeys will be puzzled by a task which effectively asks them to state whether a stimulus is present, and then, if not present, say whether it was an X or O. The experiment has not been carried out; but Allen-Hermanson goes on to suggest that Mole and Kelly’s alternative hypothesis is actually implausible on other grounds.  On their interpretation, for example, the blindsighted monkeys simply fail to notice a stimulus in their blind spot: yet it has been demonstrated that they cannot recognise objects as salient in monkey terms as ripe fruit when they are presented to the blind spot – so it seems unlikely that we’re dealing with something as simple as inattention.

What would it mean if monkeys did have blindsight? It would seem to show, at least, that monkeys are not automata; that they do have something which corresponds to at least one important variety of human consciousness. Allen-Hermanson proposes working further along the mammalian line, and he seems to expect that mammals and even some other vertebrates would yield similar results (he draws the line at toads).

At any rate, we’re left feeling that human consciousness is not as unique as it might have seemed.  I can’t help also feeling more strongly than before that the really unique feature of human awareness is the way it is shot through with language; we may not have the only form of consciousness, but we certainly seem to have the talkiest.