On 3/26/2018 8:24 AM, Stathis Papaioannou wrote:
On 26 March 2018 at 15:20, Brent Meeker <[email protected] <mailto:[email protected]>> wrote:On 3/25/2018 7:14 PM, Stathis Papaioannou wrote:On 26 March 2018 at 04:57, Brent Meeker <[email protected] <mailto:[email protected]>> wrote: On 3/25/2018 2:15 AM, Bruno Marchal wrote:On 21 Mar 2018, at 22:56, Brent Meeker <[email protected] <mailto:[email protected]>> wrote: On 3/21/2018 2:27 PM, Stathis Papaioannou wrote:On Thu, 22 Mar 2018 at 5:45 am, Brent Meeker <[email protected] <mailto:[email protected]>> wrote: On 3/20/2018 11:29 PM, Stathis Papaioannou wrote:On Wed, 21 Mar 2018 at 9:03 am, Brent Meeker <[email protected] <mailto:[email protected]>> wrote: On 3/20/2018 1:14 PM, Stathis Papaioannou wrote:On Wed, 21 Mar 2018 at 6:34 am, Brent Meeker <[email protected] <mailto:[email protected]>> wrote: On 3/20/2018 3:58 AM, Telmo Menezes wrote:The interesting thing is that you can draw conclusions about consciousness without being able to define it or detect it.I agree.The claim is that IF an entity is conscious THEN its consciousness will be preserved if brain function is preserved despite changing the brain substrate.Ok, this is computationalism. I also bet on computationalism, but I think we must proceed with caution and not forget that we are just assuming this to be true. Your thought experiment is convincing but is not a proof. You do expose something that I agree with: that non-computationalism sounds silly.But does it sound so silly if we propose substituting a completely different kind of computer, e.g. von Neumann architecture or one that just records everything instead of an episodic associative memory, for the brain. The Church-Turing conjecture says it can compute the same functions. But does it instantiate the same consciousness. My intuition is that it would be "conscious" but in some different way; for example by having the kind of memory you would have if you could review of a movie of any interval in your past. I think it would be conscious in the same way if you replaced neural tissue with a black box that interacted with the surrounding tissue in the same way. It doesn’t matter what is in the black box; it could even work by magic.Then why draw the line at "surrounding tissue". Why not the external enivironment? Keep expanding the part that is replaced and you replace the whole brain and the whole organism. Are you saying you can't imagine being "conscious" but in a different way? I think it is possible but I don’t think it could happen if my neurones were replaced by a functionally equivalent component. If it’s functionally equivalent, my behaviour would be unchanged,I agree with that. But you've already supposed that functional equivalence at the behavior level implies preservation of consciousness. So what I'm considering is replacements in the brain far above the neuron level, say at the level of whole functional groups of the brain, e.g. the visual system, the auditory system, the memory,... Would functional equivalence at the body/brain interface then still imply consciousness equivalence? I think it would, because I don’t think there are isolated consciousness modules in the brain. A large enough change in visual experience will be noticed by the subject, who will report that things look different. This could only happen if there is a change in the input to the language system from the visual system; but we have assumed that the output from the visual system is the same, and only the consciousness has changed, leading to a contradiction.But what about internal systems which are independent of perception...the very reason Bruno wants to talk about dream states. And I'm not necessarily asking that behavior be identical...just that the body/brain interface be the same. The "brain" may be different in how it processes input from the eyeballs and hence report verbally different perceptions. In other words, I'm wondering how much does computationalism constrain consciousness. My intuition is that there could be a lot of difference in consciousness depending on how different perceptual inputs are process and/or merged and how internal simulations are handled. To take a crude example, would it matter if the computer-brain was programmed in a functional language like LISP, an object-oriented language like Ruby, or a neural network? Of course Church-Turing says they all compute the same set of functions, but they don't do it the same wayThey can do it in the same way. They will not do it in the same way with a compiler, but will do it in the same way when you implement an interpreter in another interpreter. The extensional CT (in terms if which functions are calculated) entails the intensional CT (in terms of which computations can be processed. Babbage machine could emulate a quantum brain. It involves a relative slow-down, but the subject will not notice without external clues. In arithmetic, all possible sorts of computers are implemented infinitely often, with some special redundancy which plays a role in the computations statistics, the first person statistics and the origin of the physical appearances.You retreat into what is possible. My question is much more directly pragmatic. If I actually made a silicon based replacement for your brain that had the same input/output would you consciousness be different if the replacement processed the information differently...and how could you or we know? I have made the argument that your consciousness would not be different if the replacement processed the information differently provided that the I/O behaviour at the interface with the neural tissue was the same. This follows from consideration of what it means to be conscious, which we can do even if we can't verify or even define consciousness. If consciousness were changed but the outputs to the rest of the brain unchanged, the subject would either not notice any change (and what significance could consciousness have if a an arbitrarily large change in it would go unnoticed) or, if he did notice a change, it could not be communicated and there would be a decoupling between consciousness and behaviour from that point on.Well he might not notice the change because he can't remember how it was before the substitution (maybe it's memory and recall processes that were changed) and so the change /could be/ communicated...if it were noticed, but it isn't.There would be no point in the experiment if the change in conscious would not have been noticed anyway. People lose neurones every day as part of ageing and don't notice anything, because the change is too subtle. The experiment would have to be something very obvious, such as swapping out the subject's entire visual cortex and switching between the original, the new, and nothing, asking the subject: "I am now switching between A, B and C, tell me if you notice any difference as you look at the pictures on the screen". The subject would answer, “With B, I am blind. With A and C, I see exactly the same thing, and all the associated thoughts, emotions and so on are the same. If one is an electronic implant, I can only conclude that it works just as well as the original in generating visual experiences.”It seems to me there's something fishy about making behavior and conscious thought functionally equivalent so neither can change without a corresponding change in the other. My intuition is that there is a lot of my thinking that doesn't show up as observable behavior. No doubt it's observable at the micro-level in my brain; but not at the external level.There are thoughts that may not affect external behaviour in most circumstances but they could affect it given the appropriate input: for example, a question about what the subject is thinking. If there are thoughts that could never, under any circumstances, affect behaviour then they cannot be conscious thoughts, and they can’t be what is called “the subconscious” either, since that bubbles up occasionally and affects consciousness.
But does that mere possibility mean anything? Certainly I have many thoughts which will never be the subject of a question, "What are you thinking". Suppose that 90% of my thoughts are never evinced in external behavior. Then 90% of my consciousness might be different and no one (including me) would know the difference.
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