[ExI] Do digital computers feel?
stathisp at gmail.com
Mon Jan 30 07:58:12 UTC 2017
On 30 January 2017 at 14:59, Brent Allsop <brent.allsop at gmail.com> wrote:
On 1/21/2017 6:21 PM, Stathis Papaioannou wrote:
On 23 December 2016 at 06:23, Brent Allsop <brent.allsop at gmail.com> wrote:
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:
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
The "hard problem" and functionalism are not really related. The "hard
problem" can still be stated if consciousness is substrate dependent or if
it is due to an immortal soul.
The so called "hard problem" has lots of possible meanings. I was
referring to the problem that Chalmers refereed to and used the neural
substitution to argue for functionality. I'd love to know what you mean by
"hard problem" and how it can be stated in a substrate dependent way.
The "hard problem" is the question of why there should be any qualia at
all. If you show that redness is associated with glutamate, you have not
answered this question.
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
Well, I don't see the flaw. If just one of the input neurons in the XOR
system is changed, but it behaves in the same way, then the system behaves
in the same way. The artificial neuron detects glutamate when the original
neuron would have and sends output to the comparator neuron when the the
original neuron would have. That is what "functionally identical" means.
And in another e-mail you said:
"You are using several terms that are confusing, and might be seen as
begging the question: "representation", "qualities", "awareness". We can
agree on what behaviour is: it is that which is observable from the
outside. We can agree on what qualia are: they are private experiences
that, unlike behaviour, can only be guessed at by an external observer. I
pointed out in my previous post that by "function" I meant behaviour, while
you perhaps took it as also including qualia. So you see, it can quickly
Yes it can get confusing, and I am just not yet communicating adequately,
as you are completely missing and abstracting away the functionality I'm
trying to talk about. You do this when you say: "The artificial neuron
detects glutamate when the original neuron would have." This is incorrect
as it does not detect real physical glutamate nor it's real qualitative
functionality, it is only detecting an abstracted representation of
glutamate, represented by something physically very different, and only
working the way it does (so you can think of it as if it is behaving like
glutamate), because of a hardware translation system.
The job of the original neuron is to fire when it detects a certain
concentration of glutamate in the synapse, so the job of the artificial
neuron is to do the same. This is "real physical glutamate" that it is
detecting; otherwise, it wouldn't work.
Remember, that it is glutamate that has the redness quality.
That is what we are debating. I assume for the sake of argument that this
is so in order to see where it leads. But whether glutamate has the redness
quality or not does not have any bearing on our ability to detect its
presence and measure its concentration, for example by chromatography
The physical behavior of glutamate is the only thing in the simplified
example world that physically behaves or functions like redness. So, when
you are "detecting" real glutamate, you are detecting the physical
qualities or functionality of redness. But when you swap this out, with
something different, you are replacing it with some physical device that
behaves in a very different functional way that, by definition, is not the
functionality or physical quality of real glutamate. It is some different
physical function that has some different translation hardware which
enables you to think of it as if it was behaving like real glutamate, but
it is not at all real glutamate, nor is there any real redness
functionality going on in the artificial system. The artificial system
doesn't have redness, any more than the word red does. But you can think
of whatever is representing it, that doesn't have redness, as if it did,
only if you have adequate translation hardware.
If the artificial neuron detects real glutamate, the whole brain will
behave normally. Do you disagree with this? Do you disagree that the
artificial neuron can detect real glutamate, or do you disagree that even
if it does the whole brain will behave normally?
In the case of qualia, "functionally identical" means the same
functionality of whatever is the physical or detectable attributes of
redness, which you are abstracting away when you do this kind of
substitution. You are ignoring and swapping out the important
functionality that is the functionality of a redness experience.
Yes - I'm assuming that you're right for the sake of argument and the
redness experience is eliminated by putting in artificial neurons. But if
the artificial neurons fire at the same time the original neurons would, as
is the design requirement, the whole brain will behave normally and the
muscles it controls will behave normally. So the subject will say, "I see
red strawberries, they look exactly the same as they did before my brain
implant". Here is the problem: if the artificial neurons can behave the
same, but lack qualia, how is it that the subject cannot notice?
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