<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div><span></span></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8"><div></div><div><br></div><div><br>On 23 Dec. 2016, at 6:23 am, Brent Allsop <<a href="mailto:brent.allsop@gmail.com">brent.allsop@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div>
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<div class="moz-cite-prefix">On 12/21/2016 4:21 PM, Stathis
Papaioannou wrote:<br>
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<blockquote cite="mid:B2D43E33-BC98-40CF-BE6B-DDAAF0720175@gmail.com" type="cite">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:
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<p style="margin: 0px; font-size: 12px; line-height: normal;
font-family: Helvetica;"><span style="font-size: 12pt;"><a moz-do-not-send="true" href="http://consc.net/papers/qualia.html">http://consc.net/papers/qualia.html</a></span></p>
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</blockquote>
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and<br>
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<div class="moz-cite-prefix">On 12/22/2016 1:31 AM, Stathis
Papaioannou wrote:<br>
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<blockquote cite="mid:BD4D6AB8-D085-4B14-BC5F-FDC7BCDD9F6F@gmail.com" type="cite">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. <br>
</blockquote>
<br>
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.<br>
<br>
<a class="moz-txt-link-freetext" href="https://www.amazon.com/Mind-Children-Future-Robot-Intelligence/dp/0674576187">https://www.amazon.com/Mind-Children-Future-Robot-Intelligence/dp/0674576187</a><br>
<br>
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.<br>
<br>
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:<br>
<br>
<a class="moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/XOR_gate">https://en.wikipedia.org/wiki/XOR_gate</a><br>
<br>
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.<br>
<br>
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.<br>
<br>
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.<br></div></blockquote><br><div>Yes, but do you agree that despite the silicon-based comparator neurone you describe being physically different, the rest of the brain will function exactly the same?</div></div></div></body></html>