[ExI] Mental Phenomena

Ben Zaiboc ben at zaiboc.net
Sat Jan 18 14:44:25 UTC 2020

On Tue, 14 Jan, 2020 at 6:05 PM Ben Zaiboc wrote:

>     Here is a hypothesis that is at least theoretically testable: The
>     experience of redness is accompanied by the presence of certain
>     neural circuits in parts of the visual cortex. (in V8, in the
>     occipital lobe), and that temporarily knocking out these circuits
>     (via local electrodes, or a drug, or some other means) would
>     prevent the perception of redness (as well as all other colours,
>     quite possibly).
>     If this was done precisely enough, it would at least demonstrate
>     that the perception of colour was dependent on these circuits. If
>     some kind of neural interface was developed that could link to
>     precise sets of neurons, you could maybe even pinpoint circuits
>     that only affect the perception of a specific hue and saturation
>     of redness and not other colours. With enough investigation of
>     this kind, you could probably even tease out the entire route of a
>     large neural circuit that travels round the visual areas, the
>     thalamus and other parts of the brain, and be able to say "this
>     circuit here, is redness (Hue 0, Sat 67%) (Strawberry, as it
>     happens). If interrupting or disrupting that circuit removes that
>     specific redness quale (such that the subject would report that
>     they can't see it, and tests could verify that), then you've
>     pinned it down. You now know what that quale actually is.
Rafal Smigrodzki <rafal.smigrodzki at gmail.com> replied:
> ### I think you are on the right track in general but going in the 
> wrong direction: Qualia are best understood as properties of conscious 
> brains, rather than low- and mid-level local circuits. Pinpointing 
> which precise part of a color rosetter in the visual cortex is 
> necessary to trigger conscious perception of a specific hue doesn't 
> tell you that much. Instead I think we will understand the problem 
> better once we move up in our level of analysis, to the detailed 
> workings of whole large-scale networks within the brain.
> Most likely the answer will be a nothingburger, a huge load of details 
> and a dismissal of the question of "What are qualia, for real?", 
> rather than something groundbreaking, mystery-busting and spiritually 
> uplifting. It would be like our modern answer to "What is life?" - 
> which is just a mass of details about genetics, metabolism, control 
> theory and the like, rather than the discovery of the mystic "elan vital".
> But, who knows? Future neuroscience and AI research will maybe tell.
> Rafal

I expect you're right, and the whole brain, or at least large parts of 
it, will be involved.

Even so, it's possible that we could identify a specific pattern in the 
large-scale networks, and show that it's necessary and sufficient to 
produce the sensation of the colour 'strawberry'. To be sure, that would 
be a huge load of details, but it would also answer the question "what 
is the strawberry-colour quale?", very precisely. And I wouldn't be at 
all surprised if that answer was only valid for one specific individual. 
In fact, I'd be very surprised if it wasn't.

I suspect a clear and precise answer like this still wouldn't satisfy 
some people, though!

Another potential problem is that it might not just be specific to a 
single individual, but also to a specific point in time (i.e. it changes 
over time, because of related changes in the individuals brain due to 
experience, learning, etc.)

In fact, thinking about it, this seems inevitable.

I still think, though, that the hypothesis 'qualia are patterns of 
neural activation' can be shown to be falsifiable, given the appropriate 

Ben Zaiboc

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