Tag: mind

On LSD (don’t try this at home!)

Like many of my generation, I “experimented with drugs” in my youth. The most interesting was LSD. The extraordinary and sometimes scary effects of this drug are still vivid in my memory today and I believe they are explicable in terms of Model Theory.

The most obvious effect of LSD is on sensory perception, particularly visual effects. The visual world swirls about, with intense colouring and shading and a wealth of vibrant details. We can explain this in terms of a lack of the filtering of sensory input which occurs normally in visual perception, as well as a breakdown in the “constancies” which keep the visual world stable – for example the corollary discharge mechanism described in an earlier blog. In other words what we see is closer to the “real” sensory input than the idealised model of a visual scene which our brains normally construct for us. Normally if we look at a blank white wall we see just that – a wall painted white. Under the influence of LSD we see what is really there – every brushstroke, considerable variation in the shade of white from place to place, coloured shadows, and so on. Conversely, the wall is not static and stable as we know it to be in reality, but writhes about and changes shape as the various feedback and feedforward mechanisms which normally maintain visual stability begin to break down and reflect the shifting patterns presented to our retinas.

LSD also has a powerful effect on attention and engenders “heightened awareness”. You find yourself spending what seems like hours fixated on a flower or a blade of grass, marveling at its significance and beauty. As we have seen, in terms of Model Theory, attention is the mechanism which we use to test out hypotheses about the outside world and our place in it. LSD’s effect is not so much on attention itself, which if anything is intensified, but more on our ability to shift attention.

The distortion of sensory perception together with attentional effects, heightened awareness and indeed heightened emotions often combine to give a sense of “oneness with the universe”, sometimes tellingly referred to as “ego-death”. This immediately suggests a breakdown not just of the mental model in general, but also specifically of the self-model which we have argued is the basis of our sense of self-consciousness. In a sense we are bypassing the mental model and experiencing the world more directly – what Metzinger would call a breakdown in the “Transparent” nature of consciousness. The effect is (I imagine) very similar to a religious experience, something else which Model Theory can potentially address.

It appears that LSD works by interfering with the effect of the neurotransmitter serotonin or 5-hydroxytryptamine. This makes sense when you compare molecular structures.
image004 lsdimage002 serotonin

 

 

LSD Molecule                                  Serotonin Molecule

 

That leads to the prediction that serotonin plays an important role in the functioning of the mental model. For example based on the effects described above, we would expect it to be active within visual cortex (visual distortions) and pre-frontal cortex (attention and self-consciousness). Assuming serotonin has a predominantly inhibitory effect, LSD would act primarily by inhibiting this inhibition – a general excitatory effect.

One other striking effect of LSD is that time seems to slow down. I’m not sure how that fits in with model theory. In one sense, this maybe just reflects that so much goes on while the drug has its effects that a “trip” of eight hours or so seems to last for days, in retrospect at least. But maybe there is an explanation in terms of the running of the model. Computers all have a “clock” which keeps the steps in a program in synch – the faster the clock, the more powerful the computer. Maybe the mental model has a similar clock, intimately involved with our perception of time. More on this in later blogs perhaps.

The Hard Problem

I promised in the last blog to explain how Model Theory addresses Chalmers’ “hard problem”.  Well here we go…

Consciousness, it seems to me, is simply information organised in such a way that it observes itself.

I’m proposing that the way the mind works is in terms of a model or simulation of the known universe which includes a model of the self.  The challenge is to explain how the running of this model results in conscious experience.  My answer is that the mind model, just like any complex simulation, generates a huge amount of information.  This information is available to the sub-model of the self which uses selective attention to observe the model in action, including the sub-model itself.  The result is conscious experience.  How could it be otherwise?

Still not convinced?  OK, a little more about information.  Chalmers, as I understand him, more or less accepts that consciousness is an emergent property of information processing in the form of brain activity, but because he sees no acceptable reductive explanation of how this activity actually results in conscious experience he comes to the conclusion that consciousness is another “fundamental” property of the universe like matter, space or time (all of which are ultimately just as mysterious as consciousness!)  Interestingly, he then goes on to speculate that information is an important part of consciousness, but he makes a distinction between two aspects of information: the physical and the phenomenal.  Well as far as I’m concerned they’re the same.  Both the information in the mental model and the information available to us when we’re conscious is the same old information, which as an entity is reasonably well understood – we don’t need anything else in the form of a new fundamental property.

Admittedly, information is a rather slippery concept.  We can’t touch or feel it and in order to exist it needs to be encoded in some sort of substrate then accessed by some sort of information processing system.  Within a computer simulation the information is encoded in hardware and accessed by sub-systems implemented in software routines.  Within a mind the information is encoded in patterns of neuronal activity and accessed by other neuronal structures.  Of course we don’t have direct access to the information encoded at the lowest level of neurons firing.  The information is abstracted and aggregated into an enormously rich structure of symbols, concepts, algorithms and the like.  But this is true of information whatever its substrate.  The information in a book is abstracted into letters, sentences, descriptions, metaphors, analogies and narratives.  The information in a computer simulation is ultimately ones and zeroes – bits – but is manipulated, accessed and reported in the form of a range of complex data structures – numbers, characters, formulae, matrices, sets, images and so on, which are related in some way to the physical process being modelled.  I take it that the same sort of rich symbolic information processing underlies conscious experience.

Take any movie.  We know that it can be encoded entirely digitally.  In other words the movie is nothing more nor less than pure information encoded as a huge string of ones and zeroes.  This information is then re-encoded into patterns of pixels and sound waves and fed into our brains via our eyes, ears and sensory processing parts of the brain where it is experienced as being more or less identical to a narrative unfolding in the real world.  Now the information must have been re-encoded into the substrate of our mental model but it is still just the same information.  The only thing which has been added is our knowledge, partly innate, partly built up from experience, of how the physical world works – spatial structures, causal relationships, language and so on, which is presumably just more information, certainly in terms of Model Theory.  Note in particular that “qualia” within the movie – the redness of a rose, the sound of a gunshot – have also been encoded entirely digitally in the original movie, and that same information is presumably encoded within the mind, so I stand by my claim in an earlier blog that qualia too are in this sense “just” information.

OK, so the hypothesis is that consciousness is just information.  It’s not physical “stuff” but neither is it some mysterious ineffable quality.  There is a distinction between mind and matter but we don’t need to postulate some new sort of dualism.  The distinction is exactly the same in principle as that between the hardware and software on a computer or the narrative of a novel and the paper it’s printed on.  And there’s absolutely no problem about mind and matter interacting with each other.  The physical world impinges on us via sensory data which is experienced as information within a mental model.  And the information within our mental model can be used to fire motorneurons which send signals to our muscles which can impact the physical world.

At this point Chalmers would probably say that’s all very well but you still haven’t cracked the hard problem because just having the information in our heads isn’t enough; there’s a missing ingredient; you need something or someone to observe the information in order for it to become conscious experience.  Otherwise we might just as well be “zombies” as he puts it.

Well I propose that the missing ingredient is the recursive relationship between the model of the self and the overall mental model which contains the model of the self.  This is where our old friend J W Dunne comes in, as discussed in an earlier blog.  Recall that Dunne regards explanations in terms of an infinite regress as perfectly respectable and makes the point that we can only really understand systems which feature an infinite regress (of which there are many examples) when we examine the second term and its relationship with the first and third terms.  In the case of Model Theory I take this as meaning that the self model observes the model as a whole and is in its turn observed by a higher order model and so on.  Or more generally, the mental model both observes and is observed by itself.  I find it inconceivable that something like this could be going on without a “me” being conscious of it.

Another way of looking at this is in terms of the ancient and much derided idea of a homunculus or “little man” sitting inside our heads.  As explained in the earlier blog, I’m not sure this analogy is quite as outlandish as it’s usually painted and at least it has the virtue of feeling plausible in a common sense sort of way.  There is also some similarity between what I’m proposing and the ideas of Douglas Hofstadter and his “strange loops”.  Hofstadter wrote the celebrated book “Godel, Escher, Bach” and followed this up with “I am a Strange Loop”.  I think, like me, he’s claiming that the essence of consciousness is some kind of recursive or paradoxical feedback loop between different symbolic processing levels of the mind.  Unfortunately I find his writing almost completely impenetrable.  And like Metzinger and Dennet he concludes that the self is an illusion.  I simply don’t buy that.

So there you have it, for the time being!  My proposition is that I’m an information processing system and that my conscious experience is of information which is aware of itself.  Anyone out there like to comment?