[ExI] Red

[Ben Zaiboc]

On 01/07/2026 04:23, Brent Allsop wrote:
> Neurons are a detector of physical qualities, like redness.


No, the only things that neurons normally detect are signals from other neurons (digital signals, in the form of discrete quanta of depolarisation of the cell membrane). While it is true that they could respond to light (the colour doesn't really matter, but if you shine a light onto a neuron, it will normally fire), none actually gets into the brain, so in practice they don't.

You are also contradicting your earlier definition of 'redness'. You said that it means the subjective experience of the colour red. Using this definition, it can't be a 'physical quality'.


>   Something in our brain is behaving the way it does, because of it's subjective redness quality


This is the wrong way round. 'Subjective redness quality' is one of the things that the brain creates. It's a product, not a cause.


> , which our brain can combine into one gestalt experience of the world.  A very powerful computational ability which brute force discrete logic can't do.
>

You are claiming that there are computations that logical operations can't perform. Before going any further, you need to support that claim with some very convincing evidence or arguments, because it contradicts what we know about computation. But apart from that, we know how neurons work. Or at least enough to know that they act as integrators of incoming neural spikes from other neurons. We have successfully modelled a number of different neural circuits in digital computers, even to the extent of accurately reproducing the behaviour of an entire organism (a fruit fly). This is very strong evidence that brains don't have any extraordinary computational ability that what you call "brute force discrete logic" (which I take to mean digital logic) can't do.


> What is a 'mental construct' if not something objectively observable in our brain?


We need to be careful to distinguish between subjective experience and objectively observable phenomena. What I mean by 'mental construct', is something that is created as a subjective experience. For example, imagine a pink elephant. That is a mental construct that you've just created. No pink elephant is observable objectively, in the brain or anywhere else. It is a purely subjective phenomenon. If we were to dissect your brain, even down to the molecular level, there's no way to tell that you were thinking of a pink elephant (there are certainly no molecules with a 'pink elephant quality' for us to find).

Yes, this mental activity must be underlain by some kind of physical process. If there were no neurons or the neurons were not active, no pink elephant could be experienced, but these are still two different things. A bit like the phenomenon of an ocean wave being a different thing to, though dependent on, the movement of water molecules up and down, but a lot more complex.


> ..., there is some reason the redness quality is behaving the way we objectively observe it behaving.

Except we don't. We don't, and can't, 'objectively observe' redness, because it's not an objective phenomenon, it's a purely subjective one. We can only experience it, not measure it. You said that yourself, that 'redness' refers to the subjective experience, whereas 'red' refers to the objective light that enters our eyes. How one gives rise to the other is an interesting, and long, story that we don't completely understand yet, but it takes years of learning about neurobiology to understand what we do know.

If you mean "there is some reason we experience redness", then please just say that.

But if you have some way of objectively observing subjective phenomena, please let us know how it's done, I'm sure the entire scientific community, at the very least, would be agog.

-- 
Ben