That’s what it means to say that physicalism is substrate-dependent. There is a (simple) psycho-physical law which states that subjective experience is implemented on a specific substrate.
So is one of the properties of that specific substrate (the physical world) that it cannot be simulated by a Turing machine? I don’t know why you can’t just give a yes/no answer to that question. I’ve stated it explicitly enough times now that you just come across as deliberately obtuse by not answering it.
I think I’ve been fairly clear that I don’t deny the possibility that consciousness depends on non-computable physics. I don’t think it is the most likely explanation but it doesn’t seem to be clearly ruled out given our current understanding of the universe. Your story might be something close to the truth if the Church-Turing-Deutsch principle is false. It appears to me to be incoherent if it is true however.
I think the Church-Turing-Deutsch principle is probably true but I don’t think we can rule out the possibility that it is false. If it is true then it seems a simulation of a human running on a conventional computer would be just as conscious as a real human. If it is false then it is not possible to simulate a human being on a conventional computer and it therefore doesn’t make sense to say that such a simulation cannot be conscious because a simulation cannot be created. What if anything do you disagree with from those claims?
Your story might be something close to the truth if the Church-Turing-Deutsch principle is false. It appears to me to be incoherent if it is true however.
Because it implies the possibility of zombies, or for some other reason?
Because it implies the possibility of zombies, or for some other reason?
Basically, yes. Slightly more explicitly, it appears to say that two contradictory things are true: that a Turing machine can simulate every physical process but that there are properties arising from physical processes running directly on their ‘native’ hardware that do not arise when those same processes are simulated. That suggests either that the simulation is actually incomplete (it is missing inputs or algorithms that account for the difference) or that there is some kind of dualism going on: a mysterious and unidentifiable ‘something’ that accounts for consciousness existing in a human brain but not in a perfect simulation of a human brain.
If the missing something is not part of physics then we’re really back to dualism and not physicalism at all. It seems like an attempt to sneak dualism back in without admitting to being a dualist in polite company.
there are properties arising from physical processes running directly on their ‘native’ hardware that do not arise when those same processes are simulated.
Is subjective experience a “property”? By assumption, all the features of subjective experience have physical correlates which are preserved by the simulation. It’s just that the ‘native’ process fits a “format” that allows it to actually be experienced, whereas the simulated version does not. It seems weird to call this a dualist theory when the only commonality is an insistence on taking the problem of subjective experience seriously.
Well, I don’t think it really matters what you call it but I assume we agree that it is a something. Do you believe that it is in principle possible to differentiate between an entity that has that something and an entity that does not?
By assumption, all the features of subjective experience have physical correlates which are preserved by the simulation.
This sounds like your answer to my previous question is ‘no’. So is your position that it is not possible in principle to distinguish between a simulation of a human brain and a ‘real’ human brain but that the latter differs in that it possesses a ‘something’ that is not a function of the laws of physics and is inaccessible to any form of investigation other than introspection by the inhabitant of that brain but that is nonetheless in some sense a meaningful distinction? That sounds a lot like dualism to me.
Do you believe that it is in principle possible to differentiate between an entity that has that something and an entity that does not?
Perhaps not. ‘That something’ may be simply a model which translates the aforementioned physical properties into perceptual terms which are more familiar to us. But this begs the question of why we would be familiar with perception in the first place; “we have subjective experience, and by extension so does anything which is implemented in the same substrate as us” is a good way to escape that dilemma.
the latter differs in that it possesses a ‘something’ that is not a function of the laws of physics and is inaccessible to any form of investigation other than introspection by the inhabitant of that brain
The whole point of physicalism is that subjective experience is a function of the laws of physics, and in fact a fairly low-level function. If you want to avoid any hint of dualism, just remove the “inhabitant” (a misnomer) and the “psycho-physical bridging laws” from the model and enjoy your purely physicalistic theory. Just don’t expect it to do a good job of talking about phenomenology or qualia: physicalist theories are just weird like that.
As the saying goes, those who do not know dualism are doomed to reinvent it, poorly. Beware this tendency.
So is one of the properties of that specific substrate (the physical world) that it cannot be simulated by a Turing machine? I don’t know why you can’t just give a yes/no answer to that question. I’ve stated it explicitly enough times now that you just come across as deliberately obtuse by not answering it.
I think I’ve been fairly clear that I don’t deny the possibility that consciousness depends on non-computable physics. I don’t think it is the most likely explanation but it doesn’t seem to be clearly ruled out given our current understanding of the universe. Your story might be something close to the truth if the Church-Turing-Deutsch principle is false. It appears to me to be incoherent if it is true however.
I think the Church-Turing-Deutsch principle is probably true but I don’t think we can rule out the possibility that it is false. If it is true then it seems a simulation of a human running on a conventional computer would be just as conscious as a real human. If it is false then it is not possible to simulate a human being on a conventional computer and it therefore doesn’t make sense to say that such a simulation cannot be conscious because a simulation cannot be created. What if anything do you disagree with from those claims?
Because it implies the possibility of zombies, or for some other reason?
Basically, yes. Slightly more explicitly, it appears to say that two contradictory things are true: that a Turing machine can simulate every physical process but that there are properties arising from physical processes running directly on their ‘native’ hardware that do not arise when those same processes are simulated. That suggests either that the simulation is actually incomplete (it is missing inputs or algorithms that account for the difference) or that there is some kind of dualism going on: a mysterious and unidentifiable ‘something’ that accounts for consciousness existing in a human brain but not in a perfect simulation of a human brain.
If the missing something is not part of physics then we’re really back to dualism and not physicalism at all. It seems like an attempt to sneak dualism back in without admitting to being a dualist in polite company.
Is subjective experience a “property”? By assumption, all the features of subjective experience have physical correlates which are preserved by the simulation. It’s just that the ‘native’ process fits a “format” that allows it to actually be experienced, whereas the simulated version does not. It seems weird to call this a dualist theory when the only commonality is an insistence on taking the problem of subjective experience seriously.
Well, I don’t think it really matters what you call it but I assume we agree that it is a something. Do you believe that it is in principle possible to differentiate between an entity that has that something and an entity that does not?
This sounds like your answer to my previous question is ‘no’. So is your position that it is not possible in principle to distinguish between a simulation of a human brain and a ‘real’ human brain but that the latter differs in that it possesses a ‘something’ that is not a function of the laws of physics and is inaccessible to any form of investigation other than introspection by the inhabitant of that brain but that is nonetheless in some sense a meaningful distinction? That sounds a lot like dualism to me.
Perhaps not. ‘That something’ may be simply a model which translates the aforementioned physical properties into perceptual terms which are more familiar to us. But this begs the question of why we would be familiar with perception in the first place; “we have subjective experience, and by extension so does anything which is implemented in the same substrate as us” is a good way to escape that dilemma.
The whole point of physicalism is that subjective experience is a function of the laws of physics, and in fact a fairly low-level function. If you want to avoid any hint of dualism, just remove the “inhabitant” (a misnomer) and the “psycho-physical bridging laws” from the model and enjoy your purely physicalistic theory. Just don’t expect it to do a good job of talking about phenomenology or qualia: physicalist theories are just weird like that.
As the saying goes, those who do not know dualism are doomed to reinvent it, poorly. Beware this tendency.
Do you ever answer a direct question?