Tony Sobrado: The 'hard problem of consciousness' can be thought of in two ways that essentially overlap - why is it that a physical brain gives rise to subjective first-person qualitative experiences, or why is it that some physical things, like brains, are conscious and some physical things, like rocks, are not conscious. The issue is experience or as the noted Frank Jackson said to me ‘the experience of experience’ so to speak.

At its core, the hard problem of consciousness is to do with a how and why question, and there’s a certain overlap between the how and why question, and the whole hard problem itself is an overlap between science and philosophy. So, for example, in the case of a mechanistic type of scientific explanation we have the ‘how’-how does consciousness arise from a physical brain? Because we know they are related. The how here could entail a simple causal model like optogenetics in neuroscience, it could be a full causal theoretical role like a ‘sentience-experience marker’ or it could be a ‘consciousness meter’ for example.

And then there's the why question? Why does consciousness and experience exist? Part of this can overlap with the how question - and both can potentially be answered by neuroscience. But the why question can be more profound if considered in the following context: Why does consciousness and experience exist at all? And this could be metaphysically unanswerable, akin to asking where the laws of physics come from? You can keep on asking why and why and this could result in an infinite regress or just stop at brute necessity.

By comparison, in evolutionary psychology attempts to explain consciousness by way of stating that conscious experience serves a function for an organism to survive in its environment. This, however, only gets you halfway. This is because all the functions executed by an organism could be executed without any accompanying conscious experience. For example, plants don't have a conscious experience yet function as organisms. So functionalism doesn't fully explain why we have consciousness. 

So let's look at some potential explanations, solutions and frameworks for solving and addressing the hard problem of consciousness:

1. Due to the nature of scientific practice, the metaphysical assumptions of physicalism and causal explanation in scientific models - the very nature of a subjective experience cannot be causally explained by science, and it's something we can't actually answer i.e. you cannot compute or causally model a subjective experience.  To a certain extent this was partially endorsed by Daniel Dennett himself, but perhaps most notably in this space is Colin McGinn. 

2. This is a question that may be metaphysically unanswerable, akin to asking where the laws of physics come from? And may have an infinite regress built-in. You can keep on asking why and why and why... Even if you were to find a sentience or subjectivity ‘marker’ in the brain that could explain why we have subjective experiences, you could still ask but why? To a certain extent Joseph Levine’s explanatory gap may not be answerable.

3. Emergence - strong or weak. Things like consciousness, algorithms, abstraction and software emerge and are realized in physical properties. That is, the output (consciousness etc.) is greater than the sum of its parts (physical neurons) and this is a popular notion in physics, chemistry, biology, and also to a certain extent, philosophy of mind.

4. Physical realization - of which a major proponent is Andrew Melnyk. Here mental experience is realized in lower level elements of a physical structure. It's not quite an emergent property and may or may not require a causal chain, but consciousness is a higher level functioning property identical to a higher level function itself that is realized in a lower level physical structure. So just like poison is a higher level property that is identical to a higher level function that is physically realized in a lower level base (poison is realized in cyanide for example), consciousness is realized in the physical structure of neurons but just like poison’s relation to the lower level physical structure, consciousness is not identical to the lower level physical structure of neurons itself - it is merely realized in it. 

5. Illusionism - which generally states that certain beliefs or experiences that are commonly accepted as real in philosophy of mind are actually illusions. Illusionism comes in varying degrees starting with weak Illusionism, often endorsed by neuroscientists - and often unwittingly, that the Cartesian Theatre does not exist and there is no unified self. Tony and Philip are not absolute entities or unified mental selves but rather composite parts of interacting brain states. Moderate Illusionism espoused by Frank Jackson and others, denies that there is anything especially formal about qualia, it is just representational knowledge and thus after the colour red has been represented to you there’s no ‘special redness’ anywhere. And then there’s strong Illusionism which declares by fiat that our experiences are flat out illusions. 

6. Panpsychism: The reason the hard problem of consciousness is a problem and possibly intractable is because we've got it the wrong way round: Consciousness does not arise, come from, is, or is caused by the brain. Instead, consciousness is primary and fundamental - not the physical. So either everything is conscious, or the only thing that exists is consciousness and/or physicalism itself is false. 

And it’s with Panpsychism in mind that I come to you as one of the world's leading experts in Panpsychism, if not the leading expert. 

Historically, Panpsychism is far from a modern invention; it dates back to the ancient world. Many Greek thinkers contemplated it. In the contemporary world, the mechanistic universe with causal explanations arising out of mathematical equations and the assumptions of physicalism means most do not consider consciousness to be fundamental as it is out of kilter with the ‘physical universe’ and has deistic and theistic overtones. But yet Panpsychism argues that consciousness is fundamental and either that all things are conscious, or there is only one unified consciousness or consciousness is all that exists. Panpsychism like Emergence and Illusionism, and most things in philosophy and physics, comes in many guises!

So firstly, tell me what you understand the hard problem of consciousness to be and why you don't see any of the frameworks I listed above (except Panpsychism) as being adequate in explaining consciousness?

Philip Goff: I don’t use the term ‘hard problem of consciousness’ anymore, as many hear it as already assuming that physical reality is the primary thing, and then we have to work out how consciousness pops out of that. I don’t think David Chalmers intended it that way, but I think that’s how it’s generally understood.

I prefer the more traditional philosophical term ‘the mind-body problem’. We know that consciousness exists. We know that physical reality exists. The challenge is: How do they fit together? Is physical reality fundamental, and consciousness emerges from physical processes in the brain? Or perhaps consciousness is fundamental, and physical reality emerges from some deeper story about consciousness. Or maybe both are fundamental but radically different. Maybe consciousness is in the soul, separate to the physical workings of the body and the brain. Setting things up in this way leaves all options on the table.

The dominant scientific paradigm is that we can explain consciousness in terms of physical processes in the brain. However, despite decades of trying, we’ve never had any success at doing this. It’s not just that we don’t have the complete story. We haven’t managed to explain a single experience in terms of patterns of neural firings.

That’s not to say the science of consciousness has not made progress in other ways. It’s crucial to distinguish correlation from explanation. We’ve had some success on the correlation question, i.e. working out which forms of brain activity correlate with which kinds of experience – although even here there is little consensus on a general theory. But we’ve had zero success at explaining why those forms of brain activity correlate with feelings.

Compare this with the chemical explanation of the phase change of water, from ice, to liquid to steam. Here, the underlying chemistry gives you a satisfying explanation of the phenomenon. We’re not left asking, “But why do H2O molecules arranged in a highly ordered lattice structure behave in the rigid way solid ice does?” Once you understand how the molecules are behaving, you can understand why the substance behaves as it does. 

The difference with brain states and feelings couldn’t be starker. The story of electrochemical signalling doesn’t seem to have any connection to feelings. We can understand the details of how neurons fire, and how neurotransmitters work, and we’re still left asking, “Okay, but why does that amount to a feeling?”

Ultimately, I think the problem is that physical science is all about explaining behaviour. In the case of the phase change of water, we explain the observable behaviour in terms of the behaviour of molecules. We could push it deeper by explaining the behaviour of the molecules in terms of the atoms, or the behaviour of the atoms in terms of the behaviour of subatomic particles. Some physicists want to push this further, by positing superstrings at an even deeper level. Wherever it ends up, the whole project is a story of explaining observable behaviour.

But that’s not what we’re trying to do when we’re trying to explain consciousness. We’re not trying to explain why a system behaves a certain way. We’re trying to explain why it feels a certain way. This is just a different question, and not one physical science is set up to answer. It’s bit like saying, “Telescopes are really good for looking at the stars. Probably they’d be useful in pure mathematics too!”

So let me generally explain Panpsychism and why it's a route forward for addressing consciousness and its overlap with ‘physical’ reality. Panpsychism is the view that consciousness goes all the way down to the fundamental building blocks of the physical universe. It's a question for physicists what the fundamental building blocks are. Let’s say, for the sake of discussion, that they’re fundamental particles, like electrons and quarks. In that case, the panpsychist would claim that the fundamental particles have incredibly simple forms of experience, and the much more complex consciousness of the human or animal brain is somehow built up from these simpler forms of consciousness.

The claim is not that literally everything is conscious, despite the etymology of the word “panpsychism” – “pan” meaning “everything, and “psyche” meaning “mind”. The basic commitment is that consciousness exists at the level of fundamental physics. But it might be fairly rare at higher levels. Maybe only certain limited arrangements of particles form unified systems that are conscious in their own right.

Panpsychism turns the standard approach to consciousness upside down. Rather than starting with physical reality, and trying to get consciousness out of that, we instead start with consciousness, and try to get physical reality out of a deeper story about consciousness. And whilst nobody has managed to make sense of how consciousness could emerge from matter, I think we have managed to make sense of how matter could emerge from consciousness.

The core insight here comes from important work done in the 1920s by the philosopher and Nobel Laureate Bertrand Russell. Russell’s core insight was that physics is telling us a lot less than we think about physical reality. It’s just giving us mathematical structure, and mathematical structure can be implemented in lots of different ways. The mathematical structures of our physics could in principle be run on a powerful enough computer, which is why some philosophers recently have explored the idea that we might be living in a simulation. Alternately, if you have enough simple conscious entities, interacting in simple, predictable ways, you could realise the structure of physics.

We can’t get consciousness out of physics, but we can get physics out of consciousness. We know how to make sense of that.

Tony Sobrado: It’s interesting that you don’t use the term ‘hard problem of consciousness’ anymore as it already assumes that physical reality is the primary thing, and then we have to work out how consciousness pops out of that; so the bias is already tilted in the direction of the physical existing and being fundamental. Susan Blackmore also does not like the proposition and the implicitness behind the hard problem, but from the opposite perspective. This is because in asking how a physical brain ‘gives rise to’ consciousness already assumes, and posits a duality, that makes the proposition of the problem intractable because it assumes that consciousness and the brain are distinct in a Cartesian sense and rules out identity theory or eliminativism etc. So what the hard problem is and why it’s a problem is a matter of perspective. If you deny consciousness in a traditional sense - the Churchlands, Dennett, Michael Graziano, Keith Frankish, Karl Friston, Frank Jackson, Carlo Rovelli and Sean Carroll (although the last two are leading physicists not philosophers or neuroscientists) you dismiss the hard problem as a non sequitur because it assumes a distinct metaphysical domain for consciousness. Conversely if you do believe in formal consciousness - thinkers such as yourself, Donald Hoffman, Colin McGinn, Torin Alter, Iain McGilchrist, David Chalmers and leading philosophers of physics such as Tim Maudlin and Barry Loewer then there is an issue in attempting to compute a subjective sentient experience from a physical property like a neuron.

And this dichotomy is present at the heart of panpsychism. As you say panpsychism turns the standard approach to consciousness upside down. Rather than starting with physical reality, it starts with consciousness and thus attempts to get physical reality out of consciousness.

With this being the case doesn't panpsychism then just invert all the problems that we currently face with the hard problem of consciousness as we currently presuppose it? So instead of asking how conscious, sentient experience comes out of physical reality we now have the inverse: If consciousness is primary and fundamental, then how does physical reality come out of consciousness?

Now of course one could say, and Iain McGilchrist is one, that consciousness is all that exists and therefore physical reality doesn't exist fundamentally, which could be the case, but then you would need an explanation as to why it appears that there's an independent physical objective reality - why planes fly? And why viruses kill? Even if ‘physical reality’ does not exist you would need an explanation as to why it appears that it exists (we can explain hallucinations) or else you are left with the illusionist charge in the opposite direction and this time levied at certain branches of panpsychism. (Illusionism claims that our consciousness is merely a trick of the mind. Inverting this charge, we might ask the panpsychist: if physicalism is false, why does an independent physical reality appear so convincingly real?). Physical reality could instead be a transitional phase state of consciousness, but then you would need an explanation for these phase states.

The primary challenge for panpsychism is to provide a theoretical framework explaining how physical matter—or at least the appearance of it—emerges from a foundation of consciousness. Other such notions, like consciousness is woven into the fabric of space time or is quantum etc.still has the combination problem of how physicalism and consciousness interact?

Now solving these inversion and combination issues faced by panpsychismcan possibly be resolved by Russellian Monism which generally asserts that there are a single set of properties that underlie both consciousness and the fundamental properties posited by physics. Essentially, it posits that there are properties that underlie the structure of physics and these same properties may constitute consciousness.

But this unification accountis still problematic. Firstly, by positing that there are fundamental properties that constitute both physical properties and conscious properties, is stating that there is something more fundamental than both the physical and consciousness. And if so, not only does that need to be described, we still need an explanatory mechanism stating how both these physical and conscious properties come out of a set of more fundamental properties? That’s the first issue you need to address. Secondly by arguing that there's something more fundamental than the physical and consciousness not only requires a causal explanatory mechanism for the emergence or appearance of the physical and consciousness, but may also be moving past the paradigm of both physicalism and the mental in asimilar vein to what Chalmers has at times argued i.e. that we need to move beyond physicalism and the mental and go deeper to accommodate both a physical reality and consciousness. But if one dismissesboth physicalism and consciousness and moves beyond physicalism and consciousness to something more fundamentaldoesn’tthis produce a paradox for the hard problem of consciousness itself? Because if physicalism itself isn't true, then there is no hard problem of consciousness in the first place which means the solution sought (something more fundamental than both the physical and consciousness) is now invalid because the initial premise (combining the physical with consciousness) is not true or valid in the first place? (If physicalism and consciousness are not true in the first place then the hard problem of consciousness and its potential answers - how consciousness arises from physicalism - is also not true in the first place). Thirdly, what are your specific objections to paradigms such as emergence, physical realization, identity theory and illusionism when it comes to addressing the hard problem of consciousness?

Philip Goff: Let me address the first question - whether  panpsychism simply inverts the problems already faced by the hard problem of consciousness? The answer is yes it does. However, the point is that when you turn the problem upside down, it’s much easier to solve. We’ve had zero success trying to explain consciousness in terms of physical processes in the brain. But when it comes to doing it the other way around: explaining physical reality in terms of consciousness - the mysteries are solved because we know how to do it.

There is still the challenge that has become known as the combination problem. Panpsychists believe that fundamental particles like electrons and quarks have very simple forms of experience. But how do those conscious particles combine to form the very complex consciousness of the human or animal brain? One thing that might help in understanding this is arguing that a mind might be some extra “thing” some kind of container that holds various experiences and maybe experiences are the relationships that hold between them.

As to your challenges regarding Russellian Monism and whether it faces the same challenges as panpsychism when it comes to inverting hard problem of consciousness you say this:

Firstly, by positing that there are fundamental properties that constitute both physical properties and conscious properties, is stating that there is something more fundamental than both the physical and consciousness. And if so, not only does that need to be described, we still need an explanatory mechanism stating how both these physical and conscious properties come out of  a set of more fundamental properties.

Not exactly. For the panpsychist, all there is at the fundamental level is consciousness, or rather very simple entities that enjoy very simple experiences. Through the interactions of these very simple conscious entities, what we call “physics” emerges. Physics is just mathematics. So as long as the interactions of the simple conscious entities realize the right patterns, you’ll get the right mathematical structures and thereby you’ll get physics. Nothing more is needed!

Then you say: But if one dismisses both physicalism and consciousness and moves beyond physicalism and consciousness to something more fundamental doesn’t this produce a paradox for the hard problem of consciousness itself? Because if physicalism itself isn't true, then there is no hard problem of consciousness in the first place which means the solution sought (something more fundamental than both the physical and consciousness) is now invalid because the initial premise (combining the physical with consciousness) is not true or valid in the first place? (If physicalism and consciousness are not true in the first place then the hard problem of consciousness and its potential answers - how consciousness arises from physicalism - is also not true in the first place).

No, panpsychism isn’t positing something beneath both the physical and the mental. It’s just positing consciousness and then getting the physical out of consciousness. I think it’s possible that there is some deeper reality that is neither mental nor physical but is somehow suited to produce both. But I don’t think we should posit mystery where none is needed. We know consciousness exists because we are conscious. And we can explain everything that needs explaining with just consciousness alone. Ockham’s razor tells us that we shouldn’t believe in things that don’t play any explanatory role. I don’t see the need to believe in anything beyond consciousness.

Finally frameworks such as physical realization, emergence and identity theory are popular but are problematic I don’t advocate them  because they have the following issues: these are all forms of physicalism.With all of these forms of physicalism, the fundamental question you need to ask yourself is whether feelings and experiences are just forms of behaviour? Now, of course there is a close connection between feelings and behaviour. When you feel pain, you tend to scream and run away. But the question is: Are feelings nothing more than forms of behaviour? When I ask ‘Why is my wife feeling pain?’ am I just asking for an explanation of her behaviour or the behaviour of her inner parts?

Readers can answer for themselves, but I think it’s self-evident that feelings are more than just forms of behaviour. And if that’s right, then you’re not going to get a complete explanation of them from physical science, as physical science is exclusively focused on explaining behaviour. Consider brain states. Well brains states are defined in terms of functional role in the economy of the brain, or in terms of their chemical elements. But chemical elements are defined either in terms of what they do or in terms of their atomic components. Atoms are defined in terms of the particles that make them up. Ultimately we get down to the entities of fundamental physics, such as electrons and quarks. What does physics tell us about quarks? That they have mass and charge. How are these properties defined? Mass is about resisting acceleration and gravitational attraction. Charge is about attraction and repulsion. It’s all about behaviour. Physics is like playing chess when you don’t care what the chess pieces are made of, you just care what they do.

So it doesn’t matter whether we talk about ‘realization’ or ‘emergence’ or ‘identity’, it’s all about behavior which is inadequate when it comes to explaining feelings.

Tony Sobrado: You say ‘Let me address the first question - whether panpsychism simply inverts the problems already faced by the hard problem of consciousness? The answer is yes it does. However the point is that when you turn the problem upside down, it’s much easier to solve. We’ve had zero success trying to explain consciousness in terms of physical processes in the brain. But when it comes to doing it the other way around: explaining physical reality in terms of consciousness - the mysteries are solved because we know how to do it. There is still the challenge that has become known as the combination problem’ 

Recognizing both the physical and the mental encounters a combination problem regardless of panpsychism. For you explaining physical reality in terms of consciousness being first - the mysteries are solved because apparently we know how to do it. But for panpsychists, without a formal explanatory mechanism regarding how for example physics emerges from very simple entities that enjoy very simple experiences and thus how a mind might be some extra “thing” some kind of container that holds various experiences and maybe experiences are the relationships that hold between them. Then this strategic assertion can be equally employed by illusionists, in the opposite direction, who say they know how consciousness fits into the physical because they deny the formal ontological status of consciousness in the first place. Experience for illusionists is essentially just representationalist knowledge. So the panpsychist knows how to fit the physical into consciousness, the illusionist says they know how to fit consciousness into the physical. Ambiguity in both panpsychist and illusionist frameworks allows for the tenability of both!

So is there a specific demarcation criteria that benefits panpsychism over illusionism? Because this is rather speculative assertion that you state:

‘A mind might be some extra “thing” some kind of container that holds various experiences and maybe experiences are the relationships that hold between them’. 

One obvious distinction between panpsychism and illusionism surrounds the ontological status of experience. Panpsychists recognize it whilst illusionists deny it. But without an explanatory mechanism of how entities at the fundamental level, enjoying simple experiences, interact to produce physics we are left with the mere assumption that they do and so in the same vein illusionists are left with the assumption that experience is just representational knowledge. (Think how Frank Jackson walked back the knowledge argument and the ontological status of formal qualia). 

So what for you then what guarantees ontological status of experience in the first place?

Philip Goff: I'm not sure what you're looking for when you talk of an 'explanatory mechanism.' it sounds like you're asking for the kinds of explanations physical science provides: explaining why a system behaves as it does by postulating a mechanism. But the panpsychists explanation of physical reality isn't trying to give the kinds of explanation physical science gives; it's proposing a deeper layer of reality underneath the mechanisms of physical science. I can understand that we need more than just the bare statement "Physics is grounded in consciousness"; we want an intelligible story about how that happens. But I think I've given you that. Physics describes the mathematical structure of reality. So long as the basic conscious entities interact in the right ways to realize those mathematical structures, you get physics. I'm not sure what more you're looking for.

The worry about illusionism however is quite different. It's not that they're lacking some explanation for the emergence of consciousness. It's rather than they deny that consciousness exists, at least consciousness as we ordinarily understand it. How do I know that consciousness in that sense exists? I think we're immediately aware of our feelings and experiences, and that we grasp something of their nature from that immediate awareness. I know what a pain essentially is when I feel it. After all, a feeling is essentially defined by how it feels, and you know how it feels when you feel it. It is through our understanding of what pain essentially is that it's apparent to us that there's more to feeling pain that just behaving in a certain way, or having your parts behaving in a certain way.

Now of course illusionists would say I'm subject to some kind of illusion. Anything's possible, but I've never seen a good argument for that claim. All you can ever do in philosophy is to start with what seems most evident. And these basic facts about consciousness seem more evident than the reality of the external world.

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Philip Goff is a Professor of Philosophy at Durham University and a leading figure in the contemporary study of consciousness and metaphysics. He is widely recognized for his defense of panpsychism, the theory that consciousness is a fundamental and ubiquitous feature of the physical world, rather than a mere byproduct of brain activity. His work, including the books Galileo’s Error and Why? The Purpose of the Universe, argues for a "middle way" between materialism and traditional religion by exploring the possibility of cosmic purpose within a conscious universe. *** Tony Sobrado is a social scientist and freelance writer focusing on philosophy, science, atheism and current affairs.

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