You're not a panpsychist; in your view, as you say, "There’s [...] probably not anything it’s like to be a rock". So why so much trouble imagining a zombie world? You already believe that 99.9999% of matter in the universe has no conscious experience, so just extend that intuition to the other 0.0001% that happens to make up human bodies. Done. If you think there's no consciousness on Mars, just imagine there's also no consciousness no Earth. From a physicalist perspective, this seems like the logical conclusion, if only it weren't for the pesky detail of your own irreducibly real subjective experience sticking out like a sore thumb. But hey, if Dan Dennett can do it, so can you: just convince yourself to believe in your physicalist ideology instead of your own lyin' eyes.
If you do want to take the hard problem seriously, though, I highly recommend Philip Goff's work, and his book Galileo's Error in particular. After 30 years of reading philosophers and neuroscientists talk about this stuff, the case for panpsychism sounds about 80% less crazy to me than the case for physicalism, which strikes me as a dogma that flies in the face of the only facts I know with 100% certainty, namely, that I have subjective experiences that have no causal mechanism in the physical model of reality presented by the physicalists.
It's easy to imagine no consciousness on Mars because there do not seem to be any living beings on Mars. I can likewise imagine Earth without consciousness if I imagine it without any animal life. What I have trouble imagining is a hypothetical world in which you and I both exist, with physical bodies identical to the ones we have in this world, and yet we are not conscious in the hypothetical world even though we are conscious in this world.
Your last line is intriguing. What does it mean for subjective experiences to have no causal mechanism?
I guess what I mean is this: the set of empirical epistemological techniques that we call “science” has, since the time of Galileo, been formally restricted to the study of phenomena that can be objectively and reproducibly quantified through observation. This constraint definitionally excludes subjective experience per se. I cannot observe or reproduce your observation of your conscious experience. Thus, within the framework of science, there is no difference between a P-zombie and a conscious being. Psychology, to the extent it is a science, is restricted to studying internal mental states through the proxy of behavior, including self-reports; obviously, this technique cannot distinguish between a P-zombie and a conscious being.
Thus, from the point of view of science, phenomenal consciousness does not exist, any more than angels or devils exist. The scientific model is complete without any reference to qualia: matter in a human body, including the brain, operates as it does by following the same physical laws as a rock or a planet. The same epistemological chain of thought that leads to the conclusion that angels don’t exist — sure, some people say they see them, but we’ve never seen any physical phenomenon affected by something that could be called an angel — also leads to the conclusion that phenomenal consciousness does not exist.
It’s only when we step out of the constraints of science and consider a broader range of epistemological tools that the absurdity of this position is revealed. Descartes’ cogito is still the most succinct summary of the problem. Literally the only thing I know is that something is having experiences. Beyond that, I can start talking about the content of these experiences: the experiences seem to be from the point of view of a particular primate body, namely this one. There seems to be a larger physical world in which this body is situated. Some of the experiences seem to correspond to elements of this larger world (sensations), others not (ideas, dreams, emotions). It is only the sub-sub-set of experiences that point to an external physical world — the sensations — and the leap of faith that this apparent world is in fact real in some way that our dreams and ideas are not — upon which all of science is built. Layers upon layers of assumptions, guesses, articles of faith: this is the bedrock of science. And science tells us that our own conscious experience doesn’t exist.
This is what frustrates me about neuroscientists who make pronouncements about phenomenal consciousness. Their discipline by definition cannot tell us anything about phenomenal consciousness — just as well to ask an accountant or a garbage collector. (I say this as someone with a degree in neuroscience.)
Descartes' cogito is precisely where I start to find zombie world impossible to imagine. So you imagine a parallel universe physically identical to this one in every way except that it lacks qualia. And in that universe a zombie named Descartes says "cogito ergo sum" even though there is nothing that it is like to be him. Why did he say that? Well that universe operates according to the same physics as this one, so presumably everything that happens in it is a necessary consequence of the rules of physics. And that zombie has a physically identical brain with the same neurons with connections shaped by the same DNA and same life history as the real Descartes, and they fired in precisely the same way as the neurons in the brain of the real Decartes fired when he said "cogito ergo sum." So then presumably we can explain the zombie's utterance on physics alone in a manner like this; otherwise the zombie universe would not be possible. But the real world Decartes is physically identical to the zombie, so if we have an explanation for the zombie's utterance, we have an explanation for the real Decartes' utterance as well! And this is the implication zombie argument believers rarely acknowledge: that a possible zombie world not only means physics doesn't give rise to consciousness, it means consciousness doesn't give rise to anything, not even this conversation we are having. Zombies would have this same conversation, and we have all the same reasons for having it that they do. So what are we even talking about?
So no I cannot picture zombie world. If I can picture a world with Descartes uttering the words "cogito ergo sum" for reasons that must necessarily match the reasons the real Decartes said it, surely I am picturing a world with consciousness, even if it is not obvious how the physical rules of that universe give rise to it.
Yes, I like this way of looking at it in terms of the "cogito". What makes the argument tricky is that I do think there can be a system with convincingly similar behavior to a conscious being without being conscious itself. That explains some of the intuition of the zombie argument. But the problem for p-zombies (philosophical zombies) is the requirement to be physically identical, not just behaviorally similar. That's the part that I have trouble imagining.
Yes, this is a compelling argument. But of course I don’t believe in p-zombies — to the extent I have any intuitions about this, I am a panpsychist. So I agree with you that consciousness arises from physics, specifically, matter and consciousness are the same thing.
The p-zombie is a thought experiment that problematizes the physicalist claim that consciousness arises from physical properties of brains, because a brain giving rise to consciousness would be physically indistinguishable from a brain not giving rise to consciousness. There is no evidence for the physicalist claim that consciousness arises from anything particular to brains, or neurons, or any other particular arrangement of matter.
The question isn't whether you believe in p-zombies, it's whether you believe a physical description of the world is sufficient to describe an unconscious universe that looks like ours but something additional is needed to explain consciousness. The zombie argument is supposed to prove that, but I find zombie Descartes absurd enough that I consider zombies a stronger argument for the opposite proposition -- nothing more than the physical is needed for consciousness.
Either a physical clone of Descartes would for physical reasons do what Descartes does, in which case the physics gives rise to consciousness even if it isn't obvious how, or physics alone would not result in Descartes saying "cogito ergo sum", in which case p-zombies are also impossible and whatever is missing from physics must have observable consequences from a third person scientific perspective not just a first person one -- the brain must sometimes do things that can't be explained by known physics. I am skeptical of the latter but the zombie argument is entirely irrelevant to that sort of theory of consciousness.
Why can’t a P-zombie say “cogito ergo sum”? It’s not hard to build an electronic circuit that says “Cogito ergo sum! I’m experiencing such rich interiority right now! There is definitely something it’s like to be me!” all day long. That doesn’t make it true.
And since I know that circuit can exist — and since I know that humans are prone to projecting their own subjective consciousness onto other people, other animals, and other objects (animate or not), there seems to me to be very little evidence for anyone else experiencing qualia.
I am more optimistic about studying consciousness scientifically, although it is hard to get the terms right and the field is still in its early days.
Let's say I start out with just my subjective experience and no knowledge of the physical world. I'm okay with making that distinction. Here's where my thinking diverges from yours: As long as I have no knowledge of the physical world, then I cannot say whether or not my subjective experience is itself a physical phenomenon.
As you say, I know that something is having experiences; but I do not know the nature of that something beyond the content of those experiences. As I learn more about the physical world, by exploring it through my senses, I discover that I seem to have a physical body and that certain physical changes seem to produce different subjective experiences.
Through ever more sophisticated study, I may discover that every variation in subjective experience involves a corresponding variation in physical properties, and thereby come to the conclusion that my subjective experience is actually an emergent phenomenon within the physical world. The fact that I started my investigation with just my subjective experience does not contradict such a physicalist conclusion.
When you say “the fact remains that the “Mary” and zombie world arguments do not end up describing anything beyond those correlates.” the non-physicalist will reply – Yes, Exactly!
How is it you know about consciousness at all? Only because you have it. And no description of anything physical will take us beyond the correlates. That "is" the hard problem.
As to imagining zombies, I do it by thinking of a sophisticated robot, which you understand all the inner workings or mechanisms because you built it, but nowhere in that robot is an inner feel. So when it reports it has experience and it’s favourite food is pizza, it’s only the language centre stringing symbols together according to it's programming.
It’s easier to think this robot is a zombie than starting with Mary who is too similar to us. The exercise isn’t to imagine "what it is like" to be a zombie, because the answer is - nothing.
It’s only to show there is no contradiction in supposing we could build a robot identical to biological Mary which wouldn’t have inner experience. It would only go through the mechanistic motions.
And as you say - “That still leaves open the question of which systems have such a perspective and why they do.” That’s true, because the particular answers to those questions depends on your theory of consciousness.
Regarding the non-physicalist replying "Yes, Exactly" -- in your opinion, how strong are the original "Mary" and zombie world thought experiments as arguments against physicalism? That's what I'm grappling with. It seems to me that, in order to argue against physicalism, they must describe something non-physical, but they don't actually do so.
Regarding the sophisticated robot -- I actually agree with you that it is possible for a robot to produce convincing reports without being conscious, although I think it depends on just how those reports are being produced. A robot would not be identical to biological Mary down to the smallest detail without being biological itself, but it could simulate Mary's brain more or less accurately. A good theory of consciousness might be able to identify when a simulation is "accurate enough" for consciousness to emerge.
Consciousness starts out as non-physical. It doesn’t have physical properties like mass, charge, dimension, but instead qualia and intentionality.
That’s the hard problem for the physicalist. Because they have to find some way to show it is physical, despite not having physical properties. If that can’t be done, then physicalism is false.
Personally, I think those arguments are decisive against physicalism. But I’m no expert and I also think it’s better to think of physicalism or naturalism as a commitment to a method of inquiry rather than a settled philosophical stance. So the fact it might be decisive won’t stop the naturalist efforts toward “solving” the problem.
You're not a panpsychist; in your view, as you say, "There’s [...] probably not anything it’s like to be a rock". So why so much trouble imagining a zombie world? You already believe that 99.9999% of matter in the universe has no conscious experience, so just extend that intuition to the other 0.0001% that happens to make up human bodies. Done. If you think there's no consciousness on Mars, just imagine there's also no consciousness no Earth. From a physicalist perspective, this seems like the logical conclusion, if only it weren't for the pesky detail of your own irreducibly real subjective experience sticking out like a sore thumb. But hey, if Dan Dennett can do it, so can you: just convince yourself to believe in your physicalist ideology instead of your own lyin' eyes.
If you do want to take the hard problem seriously, though, I highly recommend Philip Goff's work, and his book Galileo's Error in particular. After 30 years of reading philosophers and neuroscientists talk about this stuff, the case for panpsychism sounds about 80% less crazy to me than the case for physicalism, which strikes me as a dogma that flies in the face of the only facts I know with 100% certainty, namely, that I have subjective experiences that have no causal mechanism in the physical model of reality presented by the physicalists.
It's easy to imagine no consciousness on Mars because there do not seem to be any living beings on Mars. I can likewise imagine Earth without consciousness if I imagine it without any animal life. What I have trouble imagining is a hypothetical world in which you and I both exist, with physical bodies identical to the ones we have in this world, and yet we are not conscious in the hypothetical world even though we are conscious in this world.
Your last line is intriguing. What does it mean for subjective experiences to have no causal mechanism?
I guess what I mean is this: the set of empirical epistemological techniques that we call “science” has, since the time of Galileo, been formally restricted to the study of phenomena that can be objectively and reproducibly quantified through observation. This constraint definitionally excludes subjective experience per se. I cannot observe or reproduce your observation of your conscious experience. Thus, within the framework of science, there is no difference between a P-zombie and a conscious being. Psychology, to the extent it is a science, is restricted to studying internal mental states through the proxy of behavior, including self-reports; obviously, this technique cannot distinguish between a P-zombie and a conscious being.
Thus, from the point of view of science, phenomenal consciousness does not exist, any more than angels or devils exist. The scientific model is complete without any reference to qualia: matter in a human body, including the brain, operates as it does by following the same physical laws as a rock or a planet. The same epistemological chain of thought that leads to the conclusion that angels don’t exist — sure, some people say they see them, but we’ve never seen any physical phenomenon affected by something that could be called an angel — also leads to the conclusion that phenomenal consciousness does not exist.
It’s only when we step out of the constraints of science and consider a broader range of epistemological tools that the absurdity of this position is revealed. Descartes’ cogito is still the most succinct summary of the problem. Literally the only thing I know is that something is having experiences. Beyond that, I can start talking about the content of these experiences: the experiences seem to be from the point of view of a particular primate body, namely this one. There seems to be a larger physical world in which this body is situated. Some of the experiences seem to correspond to elements of this larger world (sensations), others not (ideas, dreams, emotions). It is only the sub-sub-set of experiences that point to an external physical world — the sensations — and the leap of faith that this apparent world is in fact real in some way that our dreams and ideas are not — upon which all of science is built. Layers upon layers of assumptions, guesses, articles of faith: this is the bedrock of science. And science tells us that our own conscious experience doesn’t exist.
This is what frustrates me about neuroscientists who make pronouncements about phenomenal consciousness. Their discipline by definition cannot tell us anything about phenomenal consciousness — just as well to ask an accountant or a garbage collector. (I say this as someone with a degree in neuroscience.)
Descartes' cogito is precisely where I start to find zombie world impossible to imagine. So you imagine a parallel universe physically identical to this one in every way except that it lacks qualia. And in that universe a zombie named Descartes says "cogito ergo sum" even though there is nothing that it is like to be him. Why did he say that? Well that universe operates according to the same physics as this one, so presumably everything that happens in it is a necessary consequence of the rules of physics. And that zombie has a physically identical brain with the same neurons with connections shaped by the same DNA and same life history as the real Descartes, and they fired in precisely the same way as the neurons in the brain of the real Decartes fired when he said "cogito ergo sum." So then presumably we can explain the zombie's utterance on physics alone in a manner like this; otherwise the zombie universe would not be possible. But the real world Decartes is physically identical to the zombie, so if we have an explanation for the zombie's utterance, we have an explanation for the real Decartes' utterance as well! And this is the implication zombie argument believers rarely acknowledge: that a possible zombie world not only means physics doesn't give rise to consciousness, it means consciousness doesn't give rise to anything, not even this conversation we are having. Zombies would have this same conversation, and we have all the same reasons for having it that they do. So what are we even talking about?
So no I cannot picture zombie world. If I can picture a world with Descartes uttering the words "cogito ergo sum" for reasons that must necessarily match the reasons the real Decartes said it, surely I am picturing a world with consciousness, even if it is not obvious how the physical rules of that universe give rise to it.
Yes, I like this way of looking at it in terms of the "cogito". What makes the argument tricky is that I do think there can be a system with convincingly similar behavior to a conscious being without being conscious itself. That explains some of the intuition of the zombie argument. But the problem for p-zombies (philosophical zombies) is the requirement to be physically identical, not just behaviorally similar. That's the part that I have trouble imagining.
Yes, this is a compelling argument. But of course I don’t believe in p-zombies — to the extent I have any intuitions about this, I am a panpsychist. So I agree with you that consciousness arises from physics, specifically, matter and consciousness are the same thing.
The p-zombie is a thought experiment that problematizes the physicalist claim that consciousness arises from physical properties of brains, because a brain giving rise to consciousness would be physically indistinguishable from a brain not giving rise to consciousness. There is no evidence for the physicalist claim that consciousness arises from anything particular to brains, or neurons, or any other particular arrangement of matter.
The question isn't whether you believe in p-zombies, it's whether you believe a physical description of the world is sufficient to describe an unconscious universe that looks like ours but something additional is needed to explain consciousness. The zombie argument is supposed to prove that, but I find zombie Descartes absurd enough that I consider zombies a stronger argument for the opposite proposition -- nothing more than the physical is needed for consciousness.
Either a physical clone of Descartes would for physical reasons do what Descartes does, in which case the physics gives rise to consciousness even if it isn't obvious how, or physics alone would not result in Descartes saying "cogito ergo sum", in which case p-zombies are also impossible and whatever is missing from physics must have observable consequences from a third person scientific perspective not just a first person one -- the brain must sometimes do things that can't be explained by known physics. I am skeptical of the latter but the zombie argument is entirely irrelevant to that sort of theory of consciousness.
Why can’t a P-zombie say “cogito ergo sum”? It’s not hard to build an electronic circuit that says “Cogito ergo sum! I’m experiencing such rich interiority right now! There is definitely something it’s like to be me!” all day long. That doesn’t make it true.
And since I know that circuit can exist — and since I know that humans are prone to projecting their own subjective consciousness onto other people, other animals, and other objects (animate or not), there seems to me to be very little evidence for anyone else experiencing qualia.
I am more optimistic about studying consciousness scientifically, although it is hard to get the terms right and the field is still in its early days.
Let's say I start out with just my subjective experience and no knowledge of the physical world. I'm okay with making that distinction. Here's where my thinking diverges from yours: As long as I have no knowledge of the physical world, then I cannot say whether or not my subjective experience is itself a physical phenomenon.
As you say, I know that something is having experiences; but I do not know the nature of that something beyond the content of those experiences. As I learn more about the physical world, by exploring it through my senses, I discover that I seem to have a physical body and that certain physical changes seem to produce different subjective experiences.
Through ever more sophisticated study, I may discover that every variation in subjective experience involves a corresponding variation in physical properties, and thereby come to the conclusion that my subjective experience is actually an emergent phenomenon within the physical world. The fact that I started my investigation with just my subjective experience does not contradict such a physicalist conclusion.
Great article, I enjoyed the slant on this one.
When you say “the fact remains that the “Mary” and zombie world arguments do not end up describing anything beyond those correlates.” the non-physicalist will reply – Yes, Exactly!
How is it you know about consciousness at all? Only because you have it. And no description of anything physical will take us beyond the correlates. That "is" the hard problem.
As to imagining zombies, I do it by thinking of a sophisticated robot, which you understand all the inner workings or mechanisms because you built it, but nowhere in that robot is an inner feel. So when it reports it has experience and it’s favourite food is pizza, it’s only the language centre stringing symbols together according to it's programming.
It’s easier to think this robot is a zombie than starting with Mary who is too similar to us. The exercise isn’t to imagine "what it is like" to be a zombie, because the answer is - nothing.
It’s only to show there is no contradiction in supposing we could build a robot identical to biological Mary which wouldn’t have inner experience. It would only go through the mechanistic motions.
And as you say - “That still leaves open the question of which systems have such a perspective and why they do.” That’s true, because the particular answers to those questions depends on your theory of consciousness.
Thank you!
Regarding the non-physicalist replying "Yes, Exactly" -- in your opinion, how strong are the original "Mary" and zombie world thought experiments as arguments against physicalism? That's what I'm grappling with. It seems to me that, in order to argue against physicalism, they must describe something non-physical, but they don't actually do so.
Regarding the sophisticated robot -- I actually agree with you that it is possible for a robot to produce convincing reports without being conscious, although I think it depends on just how those reports are being produced. A robot would not be identical to biological Mary down to the smallest detail without being biological itself, but it could simulate Mary's brain more or less accurately. A good theory of consciousness might be able to identify when a simulation is "accurate enough" for consciousness to emerge.
Consciousness starts out as non-physical. It doesn’t have physical properties like mass, charge, dimension, but instead qualia and intentionality.
That’s the hard problem for the physicalist. Because they have to find some way to show it is physical, despite not having physical properties. If that can’t be done, then physicalism is false.
Personally, I think those arguments are decisive against physicalism. But I’m no expert and I also think it’s better to think of physicalism or naturalism as a commitment to a method of inquiry rather than a settled philosophical stance. So the fact it might be decisive won’t stop the naturalist efforts toward “solving” the problem.