[ExI] Do digital computers feel?

Brent Allsop brent.allsop at gmail.com
Thu Dec 22 19:23:20 UTC 2016

On 12/21/2016 4:21 PM, Stathis Papaioannou wrote:
> Your intuition is that in order to reproduce consciousness it may not 
> be sufficient to just reproduce the behaviour of the human brain, 
> because consciousness might reside in the actual brain substance. 
> This, I think, is what Brent is claiming. He further claims that one 
> day we may be able to work out the exact correlates of experience - 
> glutamate for red experiences for example (for illustrative purposes - 
> it wouldn't be as simple as this). But there is an argument due to 
> philosopher David Chalmers that assumes this common intuition to be 
> true and shows that it leads to absurdity:
> http://consc.net/papers/qualia.html


On 12/22/2016 1:31 AM, Stathis Papaioannou wrote:
> The theory of mind called "functionalism" holds that consciousness 
> results from the brain carrying out its business of cognition, rather 
> than from the actual substrate of the brain. This would mean that if 
> the function of the brain could be reproduced using another substrate, 
> such as a digital computer, the associated consciousness would also be 
> reproduced. The paper by Chalmers I cited is a reductio ad absurdum 
> starting with the assumption that consciousness is 
> substrate-dependent, thus establishing functionalism as the better 
> theory.

Thanks for bringing this up!  This neural substitution argument for 
functionalism was around way before Chalmers used the argument in his 
paper.  For example Hans Moravec made this same argument way back in 
1988, in his book Mind Children.


So at least Stathis Papaioannou, Hans Moravec, David Chalmers, James 
Carroll (CC-ed), and a bunch of others think this argument is sound, 
causing them to think "functionalism is the better theory" resulting in 
the apparent "hard problem" conundrum.  I think all these people are 
world leading, understanding wise, in this field, so we need to take 
this argument seriously.  But, despite this, it seems obvious to me that 
this so called "hard" problem is a simple misunderstanding of how 
phenomenal computation works below the abstracted layer - at the 
hardware quality dependent layer.

Let me describe the hardware quality dependent layer in today's 
computers in a slightly qualitatively advanced way to illustrate how 
this misunderstanding results.  One of the fundamental operations of a 
computation device is comparisons:  Is a 1 different than a zero? So 
fundamentally, today's computer circuits are composed of lots of such 
comparison gates that let you know if the voltage on one wire is the 
same as the voltage on another wire.  In other words, we are talking 
about a simple exclusive or functional operation:


So, instead of just implementing our XOR logical comparison function 
with simple voltages that are not physically very qualitatively 
different lets use neurotransmitter molecule comparisons like between 
glutamate and glycine.   Let's implement our XOR function with a 
comparison neuron that fires if two of it's input synapses are 
chemically the same and not fire if they are different.  In effect, this 
comparison neuron is a good glutamate detector.  If glutamate is being 
fed to one of it's input synapses, nothing but glutamate in the other 
will cause it to fire.

So, the complete XOR neural setup is composed of 3 significant neurons.  
There are two input neurons that can dump different nero transmitters 
into the two input synapses.  and the third comparison neuron that 
fires, if the two input synapses are chemically the same.  So let's 
perform the neural substitution on this xor gate. We first replace one 
of the input neurons with a silicone system that can function 
identically.  When it outputs a positive voltage, it is considered as 
representing what glutamate is chemically like. Outputting a zero 
voltage is considered to represent dumping something chemically 
different than glutamate into the synapse of the comparitor neuron.  At 
this point, you have to add a physical translator between this first 
silicone neuron substitutuion and the real comparitor neuron.  So when 
the silicone neuron outputs a positive voltage, the translation 
mechanism feeds glutamate to the comparison neuron.  Obviously, since 
the real neuron is receiving glutamate, it is happy, and it fires since 
it's two inputs are chemically or qualitatively the same.  Now, 
obviously, in order to replace the comparitor neuron, you also need to 
replace the other input with a translator system.  This system 
translates glutamate, coming from the second input neuron, into a 
positive voltage being fed into the newly artificial comparitor neuron.  
So, this simple XOR gate is functioning identically to the comparitor 
neuron.  It fires if the two inputs are the same, but doesn't fire if 
they are different.

With that, you should be able to see the flaw in this neural 
substitution logic.  The physical qualities being compared between these 
two functionally identical XOR systems is critically important when it 
comes to our consciousness.  That is why Thomas Nagel is wanting to know 
what the two comparison systems are physically and qualitatively like.  
The two inputs being compared, and what they are physically, 
chemichally, and qualitatively like is important to understanding the 
nature of physical qualitative comparison.  The two systems can be 
thought of as functionally the same, but the qualities of what they are 
comparing is physically very different.

Brent Allsop

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