Thank you! Yes, you are spot on! If consciousness is non-material, then all of this falls apart (as you say). But then we have another difficult problem on our hands -- how does a non-material substance interact with a physical one? Sometimes it feels like we're stuck between the interactionist problem and the hard problem. I'm looking forward to deep-diving into these sorts of questions in my newsletter.
Hi Arturo! Thank you for your comment and your very kind words.
You are right, computational functionalism is probably not the most popular philosophical view on consciousness these days. It just happens to be the most popular view among my friends and colleagues, which I must admit is not a very random sample. I haven't actually looked at the research on what the most popular philosophical view on consciousness is these days. Epiphenomenalism is surely up there. A reddit poll tells me Idealism and Panpsychism are the most popular, but that's not a random sample either. I do wonder whether the advent of LLMs has shifted the popular view?
Thanks for the link, I'm looking forward to reading your article.
I loved everything about this post. I'm a computer science professor currently lecturing computability theory so this discussion is somewhat adjacent to my classes, and I'm sure my students will love it. Incidentally, I wrote a very light-hearted post on the philosophical interpretation of the Turing test that I think echoes some of the early foundations of omputational functionalism. It's way more superficial that this article, though. I'd love to have your opinion.
Thank you, I'm honoured that you want to share it with your students! And, it would be an absolute pleasure to read your post! I'm looking forward to it :)
Interesting article. I have myself spent a lot of time thinking about this issue. I come from theoretical computer science. I have written two substack on the subjects that are talked about in this article. They shed a different light on this issue. The difference of approach is interesting I think.
On the more philosophical point of "free will" and the links between consciousness and quantum mechanics (interestingly I am talking about observations as dual aspect of free will) :
Stephen Wolfram's ideas, particularly those explored in his discussion of the Ruliad, certainly make us think. Thanks for the link, I hadn't read that article before.
Suzi, you have a real knack for tackling complex topics in a highly engaging way.
I have zero theoretical background---and, frankly, limited day-to-day interest---in neuroscience or the study of consciousness.
So it's a testament to your writing that I read this deep dive in one sitting and enjoyed it!
I certainly didn't suddenly become an expert on computational functionalism, but I do have a newfound appreciation of the premises and arguments involved. So thank you!
It's becoming clear that with all the brain and consciousness theories out there, the proof will be in the pudding. By this I mean, can any particular theory be used to create a human adult level conscious machine. My bet is on the late Gerald Edelman's Extended Theory of Neuronal Group Selection. The lead group in robotics based on this theory is the Neurorobotics Lab at UC at Irvine. Dr. Edelman distinguished between primary consciousness, which came first in evolution, and that humans share with other conscious animals, and higher order consciousness, which came to only humans with the acquisition of language. A machine with only primary consciousness will probably have to come first.
What I find special about the TNGS is the Darwin series of automata created at the Neurosciences Institute by Dr. Edelman and his colleagues in the 1990's and 2000's. These machines perform in the real world, not in a restricted simulated world, and display convincing physical behavior indicative of higher psychological functions necessary for consciousness, such as perceptual categorization, memory, and learning. They are based on realistic models of the parts of the biological brain that the theory claims subserve these functions. The extended TNGS allows for the emergence of consciousness based only on further evolutionary development of the brain areas responsible for these functions, in a parsimonious way. No other research I've encountered is anywhere near as convincing.
I post because on almost every video and article about the brain and consciousness that I encounter, the attitude seems to be that we still know next to nothing about how the brain and consciousness work; that there's lots of data but no unifying theory. I believe the extended TNGS is that theory. My motivation is to keep that theory in front of the public. And obviously, I consider it the route to a truly conscious machine, primary and higher-order.
My advice to people who want to create a conscious machine is to seriously ground themselves in the extended TNGS and the Darwin automata first, and proceed from there, by applying to Jeff Krichmar's lab at UC Irvine, possibly. Dr. Edelman's roadmap to a conscious machine is at https://arxiv.org/abs/2105.10461
My issue with the inverted color spectrum is that it's about the *subjective* experience of color, and that occurs in the brain, not the rods and cones, so a physical analysis doesn't address the question. It seems impossible to really say if the qualia I have seeing the color red is the same as anyone else's. At the lowest level, surely the exact mental states, in terms of how the neurons are firing, must differ. There must be a fair range of mental states that comprise 'human seeing the color red'.
I have a lot of sympathy for Penrose's original contention that consciousness is not computable (per the Turing Machine or lambda calculus definition). My jury is out on the latter connection with Hameroff's idea about microtubules. But many think photosynthesis uses quantum properties, and there is some recent evidence of quantum behavior in biology -- systems remaining coherent for unexpectedly long times. Nature tends to leverage everything at Her disposal, so it wouldn't at all surprise me if the most complicated system we know uses quantum effects somehow. I know a common response is that assuming two huge mysteries (quantum and consciousness) must be connected is too obvious, but being too obvious doesn't rule it out.
FWIW, while new to Substack, I've been on WordPress since 2011, and arguing in favor of skepticism about computationalism has been a frequent post topic. I think that brains are decidedly analog systems that *might* lend to physical simulation (hardware) but which I don't think can be replicated computationally -- specifically, not with software.
Thank you! The issue with the subjective experience claim against the inverted colour spectrum is that it seems like it cannot be proved or disproved. It comes down to a question of how subjective you think subjective experience actually is.
If what we think is subjective experience is actually subjective, then the best we can do is say, well, the correlation between light sensitivity at certain wavelengths is similar across people. We all tend to agree that we have more colour names in the 500-650nm range. We tend to agree about which colours are brighter than others. If we have normal colour vision, we have the same physical hardware as other people who have normal colour vision. And if we take the view that consciousness is reducible to the physical, our best guess is that colour vision is mostly similar for people with normal colour vision. But some interesting research suggests that we don’t all see colour exactly the same, there is some variation even with normal colour vision, because we don’t all have the same number of S-, M-, and L-cones. And some women (including me) have four cone types. These women see more colours in the blue-green range than people with three cone types.
Fantastic post! A year ago I started Substacking the most interesting intersection we are living in: learning, computation and everything in-between. It would have been far more meaningful had I found this spot earlier!
You have a great grip on the subject and the power of simplifying complex ideas. Keep going!
You describe our perception of colors as a linear spectrum...and it is physically. But that is not how we perceive it. We loop the bottom (red) and top (blue) of the spectrum together into a loop and glue them together with a fantasy color called purple. Honey bees perceive the spectrum from orange to ultraviolet. They tie orange and ultraviolet together into a loop with a color called "bee purple". Green is a honey bee's complementary color to bee purple.
This suggests that brains are generative in perception. Many other examples of generative perceptions exist: color constancy, Gestalt grouping, etc. How do these creative hallucinations fit into the functionalism framework? What role is logic to play with hallucinations?
Indeed! Our brains are not merely passive receivers of sensory information. They are active participants in constructing our reality.
Regarding how these creative hallucinations fit into the functionalism framework -- what a great question. I guess the functionalist -- focused on the roles or functions of mental states rather than their internal constitution -- would suggest that generative perceptions like colour constancy, Gestalt grouping, and other creative hallucinations should be viewed in terms of their functional roles. The ability to distinguish different light waves helps us navigate and interpret our environment more effectively. Maintaining a stable and coherent representations of the world despite varying conditions could be seen as an important function.
I have problems with both reductive materialism and functionalism.
As you describe, the first equates mental state with physical state. Ok, but mental state (specifically action selection) is nearly always described as a Markov process in which each state depends only on the previous state and some input. This makes each node of a Markov process a global variable...which is incompatible with evolution's incrementalism and neurological plasticity. My solution is a graph structure of behavior trees.
The problem I have with functionalism is teleological. I do not believe there is an intelligent designer that assigns a function. The brain is not designed for some anticipated future. It is a kludge forged from a long string of winning lottery tickets (unlikely but successfully adaptive mutations). That is why the brain is an architectural mess. Function is something we invent...it is not created by the process of natural selection.
I do not believe the brain is holographic. I recognize modularity when I see it. However I believe modularity arises as a consequence of computational, morphological, historical, and other constraints...not from best design practices.
Excellent overview of the computational view of the mind! I particularly like the deep dive into the inverted spectrum argument.
One argument I could see someone making is that while color seem correlated with various spectral ranges, there doesn't seem anything that mandates particular colors match with particular ranges. The response to this, I think, is that colors aren't mandated to be tied to the particular wavelengths, but everything about them seems tied to particular evolutionary affordances. The striking nature of red, for instance, is probably related to the fact that redness indicated ripe fruit to our primate ancestors.
As I noted in my comment on one of the functionalism posts, inverted qualia type arguments seem linked to an idea of experience being unrelated to behavior, epiphenomenal. If we don't accept that, if assume it makes a difference, then inverting qualia without affecting behavior seems impossible. Imagine inverting sweetness and bitterness, or pain and pleasure. It seems far less intuitive. I think inverting colors only seems so intuitive because the functions of color aren't particularly well understood, and what is isn't widely known yet.
I guess not surprisingly, I liked your evolutionary perspective on colour -- the way we perceive colours is likely shaped by their functional relevance in our evolutionary history. The red fruit example is a great illustration of this! And I really like your point about colour inversion seeming more intuitive due to our limited understanding of the function(s) of colour.
I wonder whether our knowledge of colour perception and its evolutionary basis could get to a point where we don't find the Inverted Spectrum argument for non-physical qualia to be all that compelling? In fact, there are some vision scientists who think that people with an inverted colour spectrum might actually exist. We know enough about how colour perception works and the genetics involved in colour deficits to make a reasonable prediction that red and green might be swapped in some people. If we can explain colour inversion in terms of genetics and neural wiring, then an inverted spectrum seems less mysterious.
Definitely sounds like we're on the same page for a lot of this stuff.
I do remember seeing some scientists, in interviews, saying inversions might exist. One even seemed convinced they do. Of course, scientists read philosophy too, and bring it with them into their work. I wonder if anyone has empirical reasons for that conclusion, and if so, what that might look like.
Thank you! Yes, you are spot on! If consciousness is non-material, then all of this falls apart (as you say). But then we have another difficult problem on our hands -- how does a non-material substance interact with a physical one? Sometimes it feels like we're stuck between the interactionist problem and the hard problem. I'm looking forward to deep-diving into these sorts of questions in my newsletter.
In my view this is not the standard view on consciousness. Epiphenomenalism imply that we simply cannot know what physical systems are conscient:
https://www.lesswrong.com/posts/nY7oAdy5odfGqE7mQ/freedom-under-naturalistic-dualism
In any case, your post is fantastic.
Hi Arturo! Thank you for your comment and your very kind words.
You are right, computational functionalism is probably not the most popular philosophical view on consciousness these days. It just happens to be the most popular view among my friends and colleagues, which I must admit is not a very random sample. I haven't actually looked at the research on what the most popular philosophical view on consciousness is these days. Epiphenomenalism is surely up there. A reddit poll tells me Idealism and Panpsychism are the most popular, but that's not a random sample either. I do wonder whether the advent of LLMs has shifted the popular view?
Thanks for the link, I'm looking forward to reading your article.
I loved everything about this post. I'm a computer science professor currently lecturing computability theory so this discussion is somewhat adjacent to my classes, and I'm sure my students will love it. Incidentally, I wrote a very light-hearted post on the philosophical interpretation of the Turing test that I think echoes some of the early foundations of omputational functionalism. It's way more superficial that this article, though. I'd love to have your opinion.
https://blog.apiad.net/p/can-machines-think
Thank you, I'm honoured that you want to share it with your students! And, it would be an absolute pleasure to read your post! I'm looking forward to it :)
Interesting article. I have myself spent a lot of time thinking about this issue. I come from theoretical computer science. I have written two substack on the subjects that are talked about in this article. They shed a different light on this issue. The difference of approach is interesting I think.
On the computability theory angle :
https://spearoflugh.substack.com/p/mathematical-necessity-nature-and
On the more philosophical point of "free will" and the links between consciousness and quantum mechanics (interestingly I am talking about observations as dual aspect of free will) :
https://spearoflugh.substack.com/p/free-will-and-observation
Ah, I see you too are a fan of pondering the juicy questions! Thanks for kind words and the links :)
Love this series!
Thank you!
Stephen Wolfram would say certainly, considering the entire universe, even multiverse, is computational:
https://writings.stephenwolfram.com/2021/11/the-concept-of-the-ruliad/
As I read that I was reminded of the quote “There's a fine line between genius and insanity.”
Stephen Wolfram's ideas, particularly those explored in his discussion of the Ruliad, certainly make us think. Thanks for the link, I hadn't read that article before.
Take it all with a massive grain of salt though: https://www.scientificamerican.com/article/physicists-criticize-stephen-wolframs-theory-of-everything/
This is also relevant: https://www.consc.net/papers/qualia.html
Suzi, you have a real knack for tackling complex topics in a highly engaging way.
I have zero theoretical background---and, frankly, limited day-to-day interest---in neuroscience or the study of consciousness.
So it's a testament to your writing that I read this deep dive in one sitting and enjoyed it!
I certainly didn't suddenly become an expert on computational functionalism, but I do have a newfound appreciation of the premises and arguments involved. So thank you!
Thank you so much. Comments like this are pure joy. I'm so happy you enjoyed it!
Such a lovely essay. Thank you. I will be a while chasing all this down and contemplating on it.
Thank you for the kind words, John!
It's becoming clear that with all the brain and consciousness theories out there, the proof will be in the pudding. By this I mean, can any particular theory be used to create a human adult level conscious machine. My bet is on the late Gerald Edelman's Extended Theory of Neuronal Group Selection. The lead group in robotics based on this theory is the Neurorobotics Lab at UC at Irvine. Dr. Edelman distinguished between primary consciousness, which came first in evolution, and that humans share with other conscious animals, and higher order consciousness, which came to only humans with the acquisition of language. A machine with only primary consciousness will probably have to come first.
What I find special about the TNGS is the Darwin series of automata created at the Neurosciences Institute by Dr. Edelman and his colleagues in the 1990's and 2000's. These machines perform in the real world, not in a restricted simulated world, and display convincing physical behavior indicative of higher psychological functions necessary for consciousness, such as perceptual categorization, memory, and learning. They are based on realistic models of the parts of the biological brain that the theory claims subserve these functions. The extended TNGS allows for the emergence of consciousness based only on further evolutionary development of the brain areas responsible for these functions, in a parsimonious way. No other research I've encountered is anywhere near as convincing.
I post because on almost every video and article about the brain and consciousness that I encounter, the attitude seems to be that we still know next to nothing about how the brain and consciousness work; that there's lots of data but no unifying theory. I believe the extended TNGS is that theory. My motivation is to keep that theory in front of the public. And obviously, I consider it the route to a truly conscious machine, primary and higher-order.
My advice to people who want to create a conscious machine is to seriously ground themselves in the extended TNGS and the Darwin automata first, and proceed from there, by applying to Jeff Krichmar's lab at UC Irvine, possibly. Dr. Edelman's roadmap to a conscious machine is at https://arxiv.org/abs/2105.10461
Another good post!
My issue with the inverted color spectrum is that it's about the *subjective* experience of color, and that occurs in the brain, not the rods and cones, so a physical analysis doesn't address the question. It seems impossible to really say if the qualia I have seeing the color red is the same as anyone else's. At the lowest level, surely the exact mental states, in terms of how the neurons are firing, must differ. There must be a fair range of mental states that comprise 'human seeing the color red'.
I have a lot of sympathy for Penrose's original contention that consciousness is not computable (per the Turing Machine or lambda calculus definition). My jury is out on the latter connection with Hameroff's idea about microtubules. But many think photosynthesis uses quantum properties, and there is some recent evidence of quantum behavior in biology -- systems remaining coherent for unexpectedly long times. Nature tends to leverage everything at Her disposal, so it wouldn't at all surprise me if the most complicated system we know uses quantum effects somehow. I know a common response is that assuming two huge mysteries (quantum and consciousness) must be connected is too obvious, but being too obvious doesn't rule it out.
FWIW, while new to Substack, I've been on WordPress since 2011, and arguing in favor of skepticism about computationalism has been a frequent post topic. I think that brains are decidedly analog systems that *might* lend to physical simulation (hardware) but which I don't think can be replicated computationally -- specifically, not with software.
Thank you! The issue with the subjective experience claim against the inverted colour spectrum is that it seems like it cannot be proved or disproved. It comes down to a question of how subjective you think subjective experience actually is.
If what we think is subjective experience is actually subjective, then the best we can do is say, well, the correlation between light sensitivity at certain wavelengths is similar across people. We all tend to agree that we have more colour names in the 500-650nm range. We tend to agree about which colours are brighter than others. If we have normal colour vision, we have the same physical hardware as other people who have normal colour vision. And if we take the view that consciousness is reducible to the physical, our best guess is that colour vision is mostly similar for people with normal colour vision. But some interesting research suggests that we don’t all see colour exactly the same, there is some variation even with normal colour vision, because we don’t all have the same number of S-, M-, and L-cones. And some women (including me) have four cone types. These women see more colours in the blue-green range than people with three cone types.
I'm envious. The blue-green range is my favorite! 🟦🟩
Fantastic post! A year ago I started Substacking the most interesting intersection we are living in: learning, computation and everything in-between. It would have been far more meaningful had I found this spot earlier!
You have a great grip on the subject and the power of simplifying complex ideas. Keep going!
Thanks so much, Nirav!
You describe our perception of colors as a linear spectrum...and it is physically. But that is not how we perceive it. We loop the bottom (red) and top (blue) of the spectrum together into a loop and glue them together with a fantasy color called purple. Honey bees perceive the spectrum from orange to ultraviolet. They tie orange and ultraviolet together into a loop with a color called "bee purple". Green is a honey bee's complementary color to bee purple.
This suggests that brains are generative in perception. Many other examples of generative perceptions exist: color constancy, Gestalt grouping, etc. How do these creative hallucinations fit into the functionalism framework? What role is logic to play with hallucinations?
Indeed! Our brains are not merely passive receivers of sensory information. They are active participants in constructing our reality.
Regarding how these creative hallucinations fit into the functionalism framework -- what a great question. I guess the functionalist -- focused on the roles or functions of mental states rather than their internal constitution -- would suggest that generative perceptions like colour constancy, Gestalt grouping, and other creative hallucinations should be viewed in terms of their functional roles. The ability to distinguish different light waves helps us navigate and interpret our environment more effectively. Maintaining a stable and coherent representations of the world despite varying conditions could be seen as an important function.
What do you think?
I have problems with both reductive materialism and functionalism.
As you describe, the first equates mental state with physical state. Ok, but mental state (specifically action selection) is nearly always described as a Markov process in which each state depends only on the previous state and some input. This makes each node of a Markov process a global variable...which is incompatible with evolution's incrementalism and neurological plasticity. My solution is a graph structure of behavior trees.
The problem I have with functionalism is teleological. I do not believe there is an intelligent designer that assigns a function. The brain is not designed for some anticipated future. It is a kludge forged from a long string of winning lottery tickets (unlikely but successfully adaptive mutations). That is why the brain is an architectural mess. Function is something we invent...it is not created by the process of natural selection.
I do not believe the brain is holographic. I recognize modularity when I see it. However I believe modularity arises as a consequence of computational, morphological, historical, and other constraints...not from best design practices.
Excellent overview of the computational view of the mind! I particularly like the deep dive into the inverted spectrum argument.
One argument I could see someone making is that while color seem correlated with various spectral ranges, there doesn't seem anything that mandates particular colors match with particular ranges. The response to this, I think, is that colors aren't mandated to be tied to the particular wavelengths, but everything about them seems tied to particular evolutionary affordances. The striking nature of red, for instance, is probably related to the fact that redness indicated ripe fruit to our primate ancestors.
As I noted in my comment on one of the functionalism posts, inverted qualia type arguments seem linked to an idea of experience being unrelated to behavior, epiphenomenal. If we don't accept that, if assume it makes a difference, then inverting qualia without affecting behavior seems impossible. Imagine inverting sweetness and bitterness, or pain and pleasure. It seems far less intuitive. I think inverting colors only seems so intuitive because the functions of color aren't particularly well understood, and what is isn't widely known yet.
I guess not surprisingly, I liked your evolutionary perspective on colour -- the way we perceive colours is likely shaped by their functional relevance in our evolutionary history. The red fruit example is a great illustration of this! And I really like your point about colour inversion seeming more intuitive due to our limited understanding of the function(s) of colour.
I wonder whether our knowledge of colour perception and its evolutionary basis could get to a point where we don't find the Inverted Spectrum argument for non-physical qualia to be all that compelling? In fact, there are some vision scientists who think that people with an inverted colour spectrum might actually exist. We know enough about how colour perception works and the genetics involved in colour deficits to make a reasonable prediction that red and green might be swapped in some people. If we can explain colour inversion in terms of genetics and neural wiring, then an inverted spectrum seems less mysterious.
Definitely sounds like we're on the same page for a lot of this stuff.
I do remember seeing some scientists, in interviews, saying inversions might exist. One even seemed convinced they do. Of course, scientists read philosophy too, and bring it with them into their work. I wonder if anyone has empirical reasons for that conclusion, and if so, what that might look like.