My scenario violates the assumption that a conscious being consists of independent replaceable parts.
Just to be concrete: let’s suppose that the fundamental physical reality consists of knotted loops in three-dimensional space. Geometry comes from a ubiquitous background of linked simple loops like chain-mail, other particles and forces are other sorts of loops woven through this background, and physical change is change in the topology of the weave.
Add to this the idea that consciousness is always a state of a single loop, that the property of the loop which matters is its topology, and that the substrate of human consciousness is a single incredibly complex loop. Maybe it’s an electromagnetic flux-loop, coiled around the microtubules of a billion cortical neurons.
In such a scenario, to replace one of these “consciousness neurons”, you don’t just emulate an input-output function, you have to reproduce the coupling between local structures and the extended single object which is the true locus of consciousness. Maybe some nano-solenoids embedded in your solid-state neuromorphic chips can do the trick.
Bear in mind that the “conscious loop” in this story is not meant to be epiphenomenal. Again, I’ll just make up some details: information is encoded in the topology of the loop, the loop topology interacts with electron bands in the microtubules, the electrons in the microtubules feel the action potential and modulate the transport of neurotransmitters to the vesicles. The single extended loop interacts with the localized information processing that we know from today’s neuroscience.
So what would happen if you progressively replaced the neurons of a brain with elements that simply did not provide an anchor for an extended loop? Let’s suppose that, instead of having nano-solenoids anchoring a single conscious flux-loop, you just have an extra type of message-passing between the neurochips, which emulates the spooling of flux-topological information. The answer is that you now have a “zombie”, an unconscious entity which has been designed in imitation of a conscious being.
Of course, all these hypotheses and details are just meant to be illustrative. I expect that the actual tie between consciousness and microphysics will be harder to understand than “conscious information maps to knots in a loop of flux”.
So what would happen if you progressively replaced the neurons of a brain with elements that simply did not provide an anchor for an extended loop? Let’s suppose that, instead of having nano-solenoids anchoring a single conscious flux-loop, you just have an extra type of message-passing between the neurochips, which emulates the spooling of flux-topological information. The answer is that you now have a “zombie”, an unconscious entity which has been designed in imitation of a conscious being.
This is done one neuron at a time, though, with the person awake and narrating what they feel so that we can see if everything is going fine. Shouldn’t some sequence of neuron replacement lead to the replacement of neurons that were previously providing consciously accessible qualia to the remaining biological neurons that still host most of the person’s consciousness? And shouldn’t this lead to a noticeable cognitive impairment they can report, if they’re still using their biological neurons to control speech (we’d probably want to keep this the case as long as possible)?
Is this really a thing where you can’t actually go ahead and say that if the theory is true, the simple neurons-as-black-boxes replacement procedure should lead to progressive cognitive impairment and probably catatonia, and if the person keeps saying everything is fine throughout the procedure, then there might be something to the hypothesis of people being made of parts after all? This isn’t building a chatbot that has been explicitly designed to mimic high-level human behavior. The neuron replacers know about neurons, nothing more. If our model of what neurons do is sufficiently wrong, then the aggregate of simulated neurons isn’t going to go zombie, it’s just not going to work because it’s copying the original connectome that only makes sense if all the relevant physics are in play.
My basic point was just that, if consciousness is only a property of a specific physical entity (e.g. a long knotted loop of planck-flux), and if your artificial brain doesn’t contain any of those (e.g. it is made entirely of short trivial loops of planck-flux), then it won’t be conscious, even if it simulates such an entity.
I will address your questions in a moment, but first I want to put this discussion back in context.
Qualia are part of reality, but they are not part of our current physical theory. Therefore, if we are going to talk about them at all, while focusing on brains, there is going to be some sort of dualism. In this discussion, there are two types of property dualism under consideration.
According to one, qualia, and conscious states generally, are correlated with computational states which are coarse-grainings of the microphysical details of the brain. Coarse-graining means that the vast majority of those details do not matter for the definition of the computational state.
According to the other sort of theory, which I have been advocating, qualia and conscious states map to some exact combination of exact microphysical properties. The knotted loop of planck-flux, winding through the graviton weave in the vicinity of important neurons, etc., has been introduced to make this option concrete.
My actual opinion is that neither of these is likely to be correct, but that the second should be closer to the truth than the first. I would like to get away from property dualism entirely, but it will be hard to do that if the physical correlate of consciousness is a coarse-grained computational state, because there is already a sort of dualism built into that concept—a dualism between the exact microphysical state and the coarse-grained state. These coarse-grained states are conceptual constructs, equivalence classes that are vague at the edges and with no
prospect of being made exact in a nonarbitrary way, so are they just intrinsically unpromising as an ontological substrate for consciousness. I’m not arguing with the validity of computational neuroscience and coarse-grained causal analysis, I’m just saying it’s not the whole story. When we get to the truth about mind and matter, it’s going to be more new-age than it is cyberpunk, more organic than it is algorithmic, more physical than it is virtual. You can’t create consciousness just by pushing bits around, it’s something far more embedded in the substance of reality. That’s my “prediction”.
Now back to your comment. You say, if consciousness—and conscious cognition—really depends on some exotic quantum entity woven through the familiar neurons, shouldn’t progressive replacement of biological neurons with non-quantum prostheses lead to a contraction of conscious experience and an observable alteration and impairment of behavior, as the substitution progresses? I agree that this is a reasonable expectation, if you have in mind Hans Moravec’s specific scenario, in which neurons are being replaced one at a time and while the subject is intellectually active and interacting with their environment.
Whether Moravec’s scenario is itself reasonable is another thing. There are about 30 million seconds in a year and there are billions of neurons just in the cortex alone. The cortical neurons are very entangled with each
other via their axons. It would be very remarkable if a real procedure of whole-brain neural substitution didn’t involve periods of functional impairment, as major modules of the brain are removed and then replaced with prosthesis.
I also find it very unlikely that attempting a Moravec procedure of neuronal replacement, and seeing what happens, will be important as a test of such rival paradigms of consciousness. I suppose you’re thinking in terms of a hypothetical computational theory of neurons whose advocates consider it good enough to serve as the basis of a Moravec procedure, versus skeptics who think that something is being left out of the model.
But inserting functional replacements for individual cortical neurons in vivo will require very advanced technology. For people wishing to conduct experiments in mind emulation, it will be much easier to employ the freeze-slice-and-scan paradigm currently contemplated for C. elegans, plus state-machine models from functional imaging for brain regions where function really is coarser in its implementation. Meanwhile, on the quantum side, while there certainly need to be radical advances in the application of concepts from condensed-matter physics to living matter, if the hypothesized quantum aspects of neuronal function are to be located… I think the really big advances that are required, must be relatively simple. Alien to our current understandings, which is why they are hard to attain, but nonetheless simple, in the way that the defining concepts of physics are simple.
There ought to be a physical-ontological paradigm which simultaneously (1) explains the reality behind some theory-of-everything mathematical formalism (2) explains how a particular class of entities from the theory can be understood as conscious entities (3) makes it clear how a physical system like the human brain could contain one such entity with the known complexity of human consciousness. Because it has to forge a deep connection between two separate spheres of human knowledge—natural science and phenomenology of consciousness—new basic principles are needed, not just technical elaborations of known ways of thinking. So neurohacking exercises like brain emulation are likely to be not very relevant to the discovery of such a paradigm. It will come from inspired high-level thinking, working with a few crucial facts; and then the paradigm will be used to guide the neurohacking—it’s the thing that will allow us to know what we’re doing.
My scenario violates the assumption that a conscious being consists of independent replaceable parts.
Just to be concrete: let’s suppose that the fundamental physical reality consists of knotted loops in three-dimensional space. Geometry comes from a ubiquitous background of linked simple loops like chain-mail, other particles and forces are other sorts of loops woven through this background, and physical change is change in the topology of the weave.
Add to this the idea that consciousness is always a state of a single loop, that the property of the loop which matters is its topology, and that the substrate of human consciousness is a single incredibly complex loop. Maybe it’s an electromagnetic flux-loop, coiled around the microtubules of a billion cortical neurons.
In such a scenario, to replace one of these “consciousness neurons”, you don’t just emulate an input-output function, you have to reproduce the coupling between local structures and the extended single object which is the true locus of consciousness. Maybe some nano-solenoids embedded in your solid-state neuromorphic chips can do the trick.
Bear in mind that the “conscious loop” in this story is not meant to be epiphenomenal. Again, I’ll just make up some details: information is encoded in the topology of the loop, the loop topology interacts with electron bands in the microtubules, the electrons in the microtubules feel the action potential and modulate the transport of neurotransmitters to the vesicles. The single extended loop interacts with the localized information processing that we know from today’s neuroscience.
So what would happen if you progressively replaced the neurons of a brain with elements that simply did not provide an anchor for an extended loop? Let’s suppose that, instead of having nano-solenoids anchoring a single conscious flux-loop, you just have an extra type of message-passing between the neurochips, which emulates the spooling of flux-topological information. The answer is that you now have a “zombie”, an unconscious entity which has been designed in imitation of a conscious being.
Of course, all these hypotheses and details are just meant to be illustrative. I expect that the actual tie between consciousness and microphysics will be harder to understand than “conscious information maps to knots in a loop of flux”.
This is done one neuron at a time, though, with the person awake and narrating what they feel so that we can see if everything is going fine. Shouldn’t some sequence of neuron replacement lead to the replacement of neurons that were previously providing consciously accessible qualia to the remaining biological neurons that still host most of the person’s consciousness? And shouldn’t this lead to a noticeable cognitive impairment they can report, if they’re still using their biological neurons to control speech (we’d probably want to keep this the case as long as possible)?
Is this really a thing where you can’t actually go ahead and say that if the theory is true, the simple neurons-as-black-boxes replacement procedure should lead to progressive cognitive impairment and probably catatonia, and if the person keeps saying everything is fine throughout the procedure, then there might be something to the hypothesis of people being made of parts after all? This isn’t building a chatbot that has been explicitly designed to mimic high-level human behavior. The neuron replacers know about neurons, nothing more. If our model of what neurons do is sufficiently wrong, then the aggregate of simulated neurons isn’t going to go zombie, it’s just not going to work because it’s copying the original connectome that only makes sense if all the relevant physics are in play.
My basic point was just that, if consciousness is only a property of a specific physical entity (e.g. a long knotted loop of planck-flux), and if your artificial brain doesn’t contain any of those (e.g. it is made entirely of short trivial loops of planck-flux), then it won’t be conscious, even if it simulates such an entity.
I will address your questions in a moment, but first I want to put this discussion back in context.
Qualia are part of reality, but they are not part of our current physical theory. Therefore, if we are going to talk about them at all, while focusing on brains, there is going to be some sort of dualism. In this discussion, there are two types of property dualism under consideration.
According to one, qualia, and conscious states generally, are correlated with computational states which are coarse-grainings of the microphysical details of the brain. Coarse-graining means that the vast majority of those details do not matter for the definition of the computational state.
According to the other sort of theory, which I have been advocating, qualia and conscious states map to some exact combination of exact microphysical properties. The knotted loop of planck-flux, winding through the graviton weave in the vicinity of important neurons, etc., has been introduced to make this option concrete.
My actual opinion is that neither of these is likely to be correct, but that the second should be closer to the truth than the first. I would like to get away from property dualism entirely, but it will be hard to do that if the physical correlate of consciousness is a coarse-grained computational state, because there is already a sort of dualism built into that concept—a dualism between the exact microphysical state and the coarse-grained state. These coarse-grained states are conceptual constructs, equivalence classes that are vague at the edges and with no prospect of being made exact in a nonarbitrary way, so are they just intrinsically unpromising as an ontological substrate for consciousness. I’m not arguing with the validity of computational neuroscience and coarse-grained causal analysis, I’m just saying it’s not the whole story. When we get to the truth about mind and matter, it’s going to be more new-age than it is cyberpunk, more organic than it is algorithmic, more physical than it is virtual. You can’t create consciousness just by pushing bits around, it’s something far more embedded in the substance of reality. That’s my “prediction”.
Now back to your comment. You say, if consciousness—and conscious cognition—really depends on some exotic quantum entity woven through the familiar neurons, shouldn’t progressive replacement of biological neurons with non-quantum prostheses lead to a contraction of conscious experience and an observable alteration and impairment of behavior, as the substitution progresses? I agree that this is a reasonable expectation, if you have in mind Hans Moravec’s specific scenario, in which neurons are being replaced one at a time and while the subject is intellectually active and interacting with their environment.
Whether Moravec’s scenario is itself reasonable is another thing. There are about 30 million seconds in a year and there are billions of neurons just in the cortex alone. The cortical neurons are very entangled with each other via their axons. It would be very remarkable if a real procedure of whole-brain neural substitution didn’t involve periods of functional impairment, as major modules of the brain are removed and then replaced with prosthesis.
I also find it very unlikely that attempting a Moravec procedure of neuronal replacement, and seeing what happens, will be important as a test of such rival paradigms of consciousness. I suppose you’re thinking in terms of a hypothetical computational theory of neurons whose advocates consider it good enough to serve as the basis of a Moravec procedure, versus skeptics who think that something is being left out of the model.
But inserting functional replacements for individual cortical neurons in vivo will require very advanced technology. For people wishing to conduct experiments in mind emulation, it will be much easier to employ the freeze-slice-and-scan paradigm currently contemplated for C. elegans, plus state-machine models from functional imaging for brain regions where function really is coarser in its implementation. Meanwhile, on the quantum side, while there certainly need to be radical advances in the application of concepts from condensed-matter physics to living matter, if the hypothesized quantum aspects of neuronal function are to be located… I think the really big advances that are required, must be relatively simple. Alien to our current understandings, which is why they are hard to attain, but nonetheless simple, in the way that the defining concepts of physics are simple.
There ought to be a physical-ontological paradigm which simultaneously (1) explains the reality behind some theory-of-everything mathematical formalism (2) explains how a particular class of entities from the theory can be understood as conscious entities (3) makes it clear how a physical system like the human brain could contain one such entity with the known complexity of human consciousness. Because it has to forge a deep connection between two separate spheres of human knowledge—natural science and phenomenology of consciousness—new basic principles are needed, not just technical elaborations of known ways of thinking. So neurohacking exercises like brain emulation are likely to be not very relevant to the discovery of such a paradigm. It will come from inspired high-level thinking, working with a few crucial facts; and then the paradigm will be used to guide the neurohacking—it’s the thing that will allow us to know what we’re doing.