[ExI] Do digital computers feel?

[Brent Allsop]

Hi Ben,


Yes, like you said, I found this in my spam folder.  And as Mike 
indicated he did, I also added a rule to gmail, so hopefully this won't 
happen again.  I'm very sorry I missed (and failed to respond to) any of 
your previous posts.  It looks like you have great stuff to say.

We seem to be having definition problems about what "red" means. I 
completely agree with everything you say about "red" things appearing 
differently in different lights and different contexts. The normal term 
"red" can mean many things, but when I talk about the property of "red", 
it always means a quality something has when it reflects something like 
650 NM light.  That is an initial causal property of the perception 
process.  The final result of a perception process is our knowledge of 
the thing reflecting 650 NM light.  This subjective knowledge has a 
redness quality to it. And as you say, the same "red" quality, can be 
represented by many different redness shades, depending on the context 
of the red.


So, in summery, a "red" property is something that reflects 650 NM 
light, and a "redness" quality is a quality of our knowledge of such.  
For all we know, my redness could be more like your greenness - both of 
which we only say represents the same "red".


Would you agree with that, and does that help?


Brent



On 2/15/2017 2:56 PM, Ben wrote:
> Brent, you'll probably ignore this as you have my other posts on this 
> subject, but I think these things still bear saying, as there are 
> spectators to all these conversations, and while a bit of 
> light-hearted bantering about how many angels can dance on the head of 
> a pin is fine, I'm uncomfortable about letting people think that most 
> of us actually believe in angels in the first place.
> That was a metaphor, by the way :D
>
> What I mean is, I have to take issue with the basic assumptions you 
> make in your arguments. e.g.:
>
> "If you strip away all the memories of red, and you strip away all 
> other information, such as yourself perceiving it, and so on, you are 
> left with just plain and simple redness"
>
> That makes as much sense as saying that if you strip away all the 
> cogs, springs and levers in a clock, you are left with just plain and 
> simple time-telling. In other words, none.
>
> It's the memories and perceptions that /create/ redness. Nothing 
> 'plain and simple' about it. This is the fundamental mistake that I 
> think you make: Assuming that complex, combinatorial phenomena are 
> actually 'fundamental properties'. They are not, and I don't see any 
> way they possibly could be. If they were, it would be possible to 
> demonstrate their existence outside of a human mind. Can you show that 
> 'red' exists outside a human mind?
>
> Aside from that, you do tend to make various simple mistakes of fact. 
> e.g. in Vol 160, Issue 3 you write:
>
> "The perception of a strawberry starts with the target of perception 
> or the surface of the strawberry having a set of physical qualities, 
> (it's ability to reflect something like 650 NM light) that we think of 
> or interpret as being "red".  There is the causally downstream set of 
> physical qualities which are very different from the set of physical 
> qualities the surface of the strawberry has. This is the 650 NM light."
>
> Fair enough so far (apart from the equivalence of 650nm light with 
> 'red', but read on), but then you say:
>
> "Then, there is a translation mechanism (the retina) which translate 
> the physical qualities of the light into a different set of physical 
> qualities (the red and green signal traveling down your optic nerve)"
>
> The crucial point here is that /there are no red and green signals in 
> the optic nerve/, in the way there are, say, 'red' and 'green' colour 
> codes in a computer. Neither is 650nm light the same thing as 'red'.
>
> There is in fact no neural representation of 'red' in our optic 
> nerves.  If you took an axon at random from the optic nerve, and 
> recorded the signals travelling down it, there is no way you, or 
> anyone else, could tell if it was signalling the presence of a 
> red-green, luminance, or blue-yellow colour channel (there's no such 
> thing as 'red', 'green', 'blue', etc., signals as such, in the visual 
> system. Search on "colour opponent theory" for details), or a light 
> patch in the left field of vision, a dark patch in the right field, an 
> edge at 65 degrees, or indeed any kind of meaningful visual stimulus, 
> without also knowing a lot more about how it's connected.
>
> At this stage of our perception, the concept of 'red' /does not yet 
> exist/. This is a crucially important fact, because it shows that the 
> perception of 'red' is not seamlessly and rigidly connected to a 'red' 
> object (meaning something that reflects ~650nm light) in our field of 
> vision. There's a very simple experiment you can do to confirm this. 
> Take a red object outside at night and look at it under moonlight. Is 
> it red? No? OK, maybe that's because the moon doesn't reflect any 
> 650nm light (do you really think this is true?), so let's try a 
> different colour. How about a yellow object? Blue? Green? Can you see 
> what I'm getting at? We don't /perceive/ something like 'red', it's 
> more that we /create/ it, in our minds, from a complex set of inputs, 
> including but by no means limited to, what comes in through our optic 
> nerves.
> Here's another example. If you have a white object, and look at it 
> through a pair of spectacles with a red filter in one eye, and a blue 
> filter in the other, what colour is the object?
>
> The only way of making sense of the signals in the optic nerve would 
> be to map exactly where an axon comes from and goes to, because visual 
> information is coded by something called 'line-labelling', where the 
> meaning of a signal is entirely dependent on what it's connected to. 
> If you took an axon that normally conveys the presence of, for 
> argument's sake, a dot of red in the centre of your right eye (as I've 
> said, it's not that simple, but never mind), and connected it to a 
> slightly different part of the lateral geniculate nucleus of the 
> thalamus to the one it normally synapses with, then that signal would 
> mean something totally different. It could even mean a sound or a stab 
> of pain in your leg, if it was moved so as to synapse with a neuron 
> just a few millimetres away from its original target. And it makes not 
> a jot of difference which neurotransmitter caused that neuron to send 
> a signal down its axon. Not does it make a jot of difference which 
> neurotransmitter it releases at its axon terminals, to the meaning of 
> the signals that the downstream neurons convey. In fact the 
> neurotransmitters, as I've alluded to in a previous post (and as 
> Stathis points out), are kind of irrelevant. They are just signals, 
> and what they convey is /completely independent of what they are/, 
> rather like a 1 and a 0 in a digital computer. "What does 1 mean?" 
> Silly question, isn't it? Ditto "what does glutamate mean?". The 
> meaning is totally dependent on the context. In our brains, that 
> context is whether the receiving neuron is positively or negatively 
> polarised by its glutamate receptors, and which other neurons it 
> synapses with. Replace glutamate with something else, and make the 
> receptors correspond, and there will be absolutely no difference. You 
> will no doubt disagree, but I insist that /glutamate on its own means 
> absolutely nothing/. Science tells us this, and if you disagree, 
> you're not just arguing with me, you're arguing against science.
>
> Philosophising about our minds is all very well, but it really does 
> have to start with some basic neurobiology, or it's totally 
> meaningless. I'm no expert in sensory neurobiology, but I know enough 
> about it to see that these ideas about red qualia etc., that you 
> propound, are totally orthogonal to the known science about how our 
> minds work. But I can also see that you're trying to convey /something/.
>
> So, the challenge is: Can you reformulate your arguments in line with 
> the known science of how the brain works? No more 'fundamental 
> redness', no more 'glutamate is red'. Stick with the science, and 
> maybe we'll understand what you're actually trying to say.
>
> Ben Zaiboc
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