Conversation with David Pearce about digital sentience and the binding problem

Whether digital sentience is possible would seem to matter greatly for our priorities, and so gaining even slightly more refined views on this matter could be quite valuable. Many people appear to treat the possibility, if not indeed the imminence, of digital sentience as a foregone conclusion. David Pearce, in contrast, is skeptical.

Pearce has written and spoken elaborately about his views on consciousness. My sense, however, is that these expositions do not always manage to clearly convey the core, and actually very simple reasons underlying Pearce’s skepticism of digital sentience. The aim of this conversation is to probe Pearce so as to shed greater — or perhaps most of all simpler — light on why he is skeptical, and thus to hopefully advance the discussions on this issue among altruists working to reduce future suffering.


MV: You are skeptical about the possibility of digital sentience. Could you explain why, in simple terms?

DP: Sure. Perhaps we can start by asking why so many people believe that our machines will become conscious (cf. https://www.hedweb.com/quora/2015.html#definition). Consciousness is widely recognised to be scientifically unexplained. But the computer metaphor of mind seems to offer us clues (cf. https://www.hedweb.com/quora/2015.html#braincomp). As far as I can tell, many if not most believers in digital sentience tend to reason along the following lines. Any well-defined cognitive task that the human mind can perform could also be performed by a programmable digital computer (cf. https://en.wikipedia.org/wiki/Turing_machine). A classical Turing machine is substrate-neutral. By “substrate-neutral”, we mean that whether a Turing machine is physically constituted of silicon or carbon or gallium oxide (etc) makes no functional difference to the execution of the program it runs. It’s commonly believed that the behaviour of a human brain can, in principle, be emulated on a classical Turing machine. Our conscious minds must be identical with states of the brain. If our minds weren’t identical with brain states, then dualism would be true (cf. https://www.hedweb.com/quora/2015.html#dualidealmat). Therefore, the behaviour of our minds can in principle be emulated by a digital computer. Moreover, the state-space of all possible minds is immense, embracing not just the consciousness of traditional and enhanced biological lifeforms, but also artificial digital minds and maybe digital superintelligence. Accordingly, the belief that non-biological information-processing machines can’t support consciousness is arbitrary. It’s unjustified carbon chauvinism.

I think most believers in digital sentience would recognise that the above considerations are not a rigorous argument for the existence of inorganic machine consciousness. The existence of machine consciousness hasn’t been derived from first principles. The “explanatory gap” is still unbridged. Yet what is the alternative?

Well, as a scientific rationalist, I’m an unbeliever. Digital computers and the software they run are not phenomenally-bound subjects of experience (cf. https://www.binding-problem.com/). Ascribing sentience to digital computers or silicon robots is, I believe, a form of anthropomorphic projection — a projection their designers encourage by giving their creations cutesy names (“Watson”, “Sophia”, “Alexa” etc). 

Before explaining my reasons for believing that digital computers are zombies, I will lay out two background assumptions. Naturally, one or both assumptions can be challenged, though I think they are well-motivated.

The first background assumption might seem scarcely relevant to your question. Perpetual direct realism is false (cf. https://www.hedweb.com/quora/2015.html#distort). Inferential realism about the external world is true. The subjective contents of your consciousness aren’t merely a phenomenally thin and subtle serial stream of logico-linguistic thought-episodes playing out behind your forehead, residual after-images when you close your eyes, inner feelings and emotions and so forth. Consciousness is also your entire phenomenal world-simulation — what naïve realists call the publicly accessible external world. Unless you have the neurological syndromes of simultanagnosia (the inability to experience more than one object at once) or akinetopsia (“motion blindness”), you can simultaneously experience a host of dynamic objects — for example, multiple players on a football pitch, or a pride of hungry lions. These perceptual objects populate your virtual world of experience from the sky above to your body-image below. Consciousness is all you directly know. The external environment is an inference, not a given.

Let’s for now postpone discussion of how our skull-bound minds are capable of such an extraordinary feat of real-time virtual world-making. The point is that if you couldn’t experience multiple feature-bound phenomenal objects — i.e. if you were just an aggregate of 86 billion membrane-bound neuronal “pixels” of experience — then you’d be helpless. Compare dreamless sleep. Like your enteric nervous system (the “brain-in-the-gut”), your mind-brain would still be a fabulously complex information-processing system. But you’d risk starving to death or getting eaten. Waking consciousness is immensely adaptive. (cf. https://www.hedweb.com/quora/2015.html#evolutionary). Phenomenal binding is immensely adaptive (cf. https://www.hedweb.com/quora/2015.html#purposecon).

My second assumption is physicalism (cf. https://www.hedweb.com/quora/2015.html#materialism). I assume the unity of science. All the special sciences (chemistry, molecular biology etc) reduce to physics. In principle, the behaviour of organic macromolecules such as self-replicating DNA can be described entirely in the mathematical language of physics without mentioning “life” at all, though such high-level description is convenient. Complications aside, no “element of reality” is missing from the mathematical formalism of our best theory of the world, quantum mechanics, or more strictly from tomorrow’s unification of quantum field theory and general relativity.

One corollary of physicalism is that only “weak” emergence is permissible. “Strong” emergence is forbidden. Just as the behaviour of programs running on your PC supervenes on the behaviour of its machine code, likewise the behaviour of biological organisms can in principle be exhaustively reduced to quantum chemistry and thus ultimately to quantum field theory. The conceptual framework of physicalism is traditionally associated with materialism. According to materialism as broadly defined, the intrinsic nature of the physical — more poetically, the mysterious “fire” in the equations — is non-experiential. Indeed, the assumption that quantum field theory describes fields of insentience is normally treated as too trivially obvious to be worth stating explicitly. However, this assumption of insentience leads to the Hard Problem of consciousness. Non-materialist physicalism (cf. https://www.hedweb.com/quora/2015.html#galileoserror) drops this plausible metaphysical assumption. If the intrinsic nature argument is sound, there is no Hard Problem of consciousness: it’s the intrinsic nature of the physical (cf. https://www.hedweb.com/quora/2015.html#definephysical ). However, both “materialist” physicalists and non-materialist physicalists agree: everything that happens in the world is constrained by the mathematical straitjacket of modern physics. Any supposedly “emergent” phenomenon must be derived, ultimately, from physics. Irreducible “strong” emergence would be akin to magic.

Anyhow, the reason I don’t believe in digital minds is that classical computers are, on the premises outlined above, incapable of phenomenal binding. If we make the standard assumption that their 1 and 0s and logic gates are non-experiential, then digital computers are zombies. Less obviously, digital computers are zombies if we don’t make this standard assumption! Imagine, fancifully, replacing non-experiential 1s and 0s of computer software with discrete “pixels” of experience. Run the program as before. The upshot will still be a zombie, more technically a micro-experiential zombie. What’s more, neither increasing the complexity of the code nor exponentially increasing the speed of its execution could cause discrete “pixels” somehow to blend into each other in virtue of their functional role, let alone create phenomenally-bound perceptual objects or a unitary self experiencing a unified phenomenal world. The same is true of a connectionist system (cf. https://en.wikipedia.org/wiki/Connectionism), supposedly more closely modelled on the brain — however well-connected and well-trained the network, and regardless whether its nodes are experiential or non-experiential. The synchronous firing of distributed feature-processors in a “trained up” connectionist system doesn’t generate a unified perceptual object — again on pain of “strong” emergence. AI programmers and roboticists can use workarounds for the inability of classical computers to bind, but they are just that: workarounds.

Those who believe in digital sentience can protest that we don’t know that phenomenal minds can’t emerge at some level of computational abstraction in digital computers. And they are right! If abstract objects have the causal power to create conscious experience, then digital computer programs might be subjects of experience. But recall we’re here assuming physicalism. If physicalism is true, then even if consciousness is fundamental to the world, we can know that digital computers are — at most — micro-experiential zombies.

Of course, monistic physicalism may be false. “Strong” emergence may be real. But if so, then reality seems fundamentally lawless. The scientific world-picture would be false.

Yet how do biological minds routinely accomplish binding if phenomenal binding is impossible for any classical digital computer (cf. https://en.wikipedia.org/wiki/Universal_Turing_machine). Even if our neurons support rudimentary “pixels” of experience, why aren’t animals like us in the same boat as classical digital computers or classically parallel connectionist systems?

I can give you my tentative answer. Naïvely, it’s the reductio ad absurdum of quantum mind: “Schrödinger’s neurons”: https://www.hedweb.com/quora/2015.html#quantumbrain.

Surprisingly, it’s experimentally falsifiable via interferometry: https://en.wikipedia.org/wiki/Quantum_mind#David_Pearce 

Yet the conjecture I explore may conceivably be of interest only to someone who already feels the force of the binding problem. Plenty of researchers would say it’s a ridiculous solution to a nonexistent problem. I agree it’s crazy; but it’s worth falsifying. Other researchers just lump phenomenal binding together with the Hard Problem (cf. https://www.hedweb.com/quora/2015.html#categorize) as one big insoluble mystery they suppose can be quarantined from the rest of scientific knowledge.

I think their defeatism and optimism alike are premature. 

MV: Thanks, David. A lot to discuss there, obviously.

Perhaps the most crucial point to really appreciate in order to understand your skepticism is that you are a strict monist about reality. That is, “the experiential” is not something over and above “the physical”, but rather identical with it (which, to be clear, does not imply that all physical things have minds, or complex experiences). And so if “the mental” and “the physical” are essentially the same ontological thing, or phenomenon, under two different descriptions, then there must, roughly speaking, also be a match in terms of their topological properties.

As Mike Johnson explained your view: “consciousness is ‘ontologically unitary’, and so only a physical property that implies ontological unity … could physically instantiate consciousness.” (Principia Qualia, p. 73). (Note that “consciousness” here refers to an ordered, composite mind; not phenomenality more generally.)

Conversely, a system that is physically discrete or disconnected — say, a computer composed of billiard balls that bump into each other, or lighthouses that exchange signals across hundreds of kilometers — could not, on your view, support a unitary mind. In terms of the analogy of thinking about consciousness as waves, your view is roughly that we should think of a unitary mind as a large, composite wave of sorts, akin to a song, whereas disconnected “pixels of experience” are like discrete microscopic proto-waves, akin to tiny disjoint blobs of sound. (And elsewhere you quote Seth Lloyd saying something similar about classical versus quantum computations: “A classical computation is like a solo voice — one line of pure tones succeeding each other. A quantum computation is like a symphony — many lines of tones interfering with one another.”)

This is why you say that “computer software with discrete ‘pixels’ of experience will still be a micro-experiential zombie”, and why you say that “even if consciousness is fundamental to the world, we can know that digital computers are at most micro-experiential zombies” — it’s because of this physical discreteness, or “disconnectedness”.

And this is where it seems to me that the computational view of mind is also starkly at odds with common sense, as well as with monism. For it seems highly counterintuitive to claim that billiard balls bumping into each other, or lighthouses separated by hundreds of kilometers that exchange discrete signals, could, even in principle, mediate a unitary mind. I wonder whether most people who hold a computational view of mind are really willing to bite this bullet. (Such views have also been elaborately criticized by Mike Johnson and Scott Aaronson — critiques that I have seen no compelling replies to.)

It also seems non-monistic in that it appears impossible to give a plausible account of where a unitary mind is supposed to be found in this picture (e.g. in a picture with discrete computations occurring serially over long distances), except perhaps as a separate, dualist phenomenon that we somehow map onto a set of physically discrete computations occurring over time, which seems to me inelegant and unparsimonious. Not to mention that it gives rise to an explosion of minds, as we can then see minds in a vast set of computations that are somehow causally connected across time and space, with the same computations being included in many distinct minds. This picture is at odds with a monist view that implies a one-to-one correspondence between concrete physical state and concrete mental state — or rather, which sees these two sides as distinct descriptions of the exact same reality.

The question is then how phenomenal binding could occur. You explore a quantum mind hypothesis involving quantum coherence. So what are your reasons for thinking that quantum coherence is necessary for phenomenal binding? Why would, say, electromagnetic fields in a synchronous state not be enough?

DP: If the phenomenal unity of mind is an effectively classical phenomenon, then I have no idea how to derive the properties of our phenomenally bound minds from decohered, effectively classical neurons — not even in principle, let alone in practice. 

MV: And why is that? What is it that makes deriving the properties of our phenomenally bound minds seem feasible in the case of coherent states, unlike in the case of decohered ones?

DP: Quantum coherent states are individual states — i.e. fundamental physical features of the world — not mere unbound aggregates of classical mind-dust. On this story, decoherence (cf. https://arxiv.org/pdf/1911.06282.pdf) explains phenomenal unbinding.

MV: So it is because only quantum coherent states could constitute the “ontological unity” of a unitary, “bound” mind. Decoherent states, on your view, are not and could not be ontologically unitary in the required sense?

DP: Yes!

Digital computing depends on effectively classical, decohered individual bits of information, whether as implemented in Turing’s original tape set-up, a modern digital computer, or indeed if the world’s population of skull-bound minds agree to participate in an experiment to see if a global mind can emerge from a supposed global brain.

One can’t create perceptual objects, let alone unified minds, from classical mind-dust even if strictly the motes of decohered “dust” are only effectively classical, i.e. phase information has leaked away into the environment. If the 1s and 0s of a digital computer are treated as discrete micro-experiential pixels, then when running a program, we don’t need to consider the possibility of coherent superpositions of 1s and 0s/ micro-experiences. If the bits weren’t effectively classical and discrete, then the program wouldn’t execute.

MV: In other words, you are essentially saying that binding/unity between decohered states is ultimately no more tenable than binding/unity between, say, two billard balls separated by a hundred miles? Because they are in a sense similarly ontologically separate?

DP: Yes!

MV: So to summarize, your argument is roughly the following: 

  1. observed phenomenal binding, or a unitary mind, combined with 
  2. an empirically well-motivated monistic physicalism, means that
  3. we must look for a unitary physical state as the “mediator”, or rather the physical description, of mind [since the ontological identity from (2) implies that the phenomenal unity from (1) must be paralleled in our physical description], and it seems that
  4. only quantum coherent states could truly fit the bill of such ontological unity in physical terms.

DP: 1 to 4, yes!

MV: Cool. And in step 4 in particular, to spell that out more clearly, the reasoning is roughly that classical states are effectively (spatiotemporally) serial, discrete, disconnected, etc. Quantum coherent states, in contrast, are a connected, unitary, individual whole.

Classical bits in a sense belong to disjoint “ontological sets”, whereas qubits belong to the same “ontological set” (as I’ve tried to illustrate somewhat clumsily below, and in line with Seth Lloyd’s quote above).

Is that a fair way to put it?

DP: Yes!

I sometimes say who will play Mendel to Zurek’s Darwin is unknown. If experience discloses the intrinsic nature of the physical, i.e. if non-materialist physicalism is true, then we must necessarily consider the nature of experience at what are intuitively absurdly short timescales in the CNS. At sufficiently fine-grained temporal resolutions, we can’t just assume the existence of decohered macromolecules, neurotransmitters, receptors, membrane-bound neurons etc. — they are weakly emergent, dynamically stable patterns of “cat states”. These high-level patterns must be derived from quantum bedrock — which of course I haven’t done. All I’ve done is make a “philosophical” conjecture that (1) quantum coherence mediates the phenomenal unity of our minds; and (2) quantum Darwinism (cf. https://www.sciencemag.org/news/2019/09/twist-survival-fittest-could-explain-how-reality-emerges-quantum-haze) offers a ludicrously powerful selection-mechanism for sculpting what would otherwise be mere phenomenally-bound “noise”.

MV: Thanks for that clarification.

I guess it’s also worth stressing that you do not claim this to be any more than a hypothesis, while you at the same time admit that you have a hard time seeing how alternative accounts could explain phenomenal binding.

Moreover, it’s worth stressing that the conjecture resulting from your line of reasoning above is in fact, as you noted, a falsifiable one — a rare distinction for a theory of consciousness.

A more general point to note is that skepticism about digital sentience need not be predicated on the conjecture you presented above, as there are other theories of mind — not necessarily involving quantum coherence — that also imply that digital computers are unable to mediate a conscious mind (including some of the theories hinted at above, and perhaps other, more recent theories). For example, one may accept steps 1-3 in the argument above, and then be more agnostic in step 4, with openness to the possibility that binding could be achieved in other ways, yet while still considering contemporary digital computers unlikely to be able to mediate a unitary mind (e.g. because of the fundamental architectural differences between such computers and biological brains).

Okay, having said all that, let’s now move on to a slightly different issue. Beyond digital sentience in particular, you have also expressed skepticism regarding artificial sentience more generally (i.e. non-digital artificial sentience). Can you explain the reasons for this skepticism?

DP: Well, aeons of posthuman biological minds probably lie ahead. They’ll be artificial — genetically rewritten, AI-augmented, most likely superhumanly blissful, but otherwise inconceivably alien to Darwinian primitives. My scepticism is about the supposed emergence of minds in classical information processors — whether programmable digital computers, classically parallel connectionist systems or anything else.

What about inorganic quantum minds? Well, I say a bit more e.g. here: https://www.hedweb.com/quora/2015.html#nonbiological

A pleasure-pain axis has been so central to our experience that sentience in everything from worms to humans is sometimes (mis)defined in terms of the capacity to feel pleasure and pain. But essentially, I see no reason to believe that such (hypothetical) phenomenally bound consciousness in future inorganic quantum computers will support a pleasure-pain axis any more than, say, the taste of garlic.

In view of our profound ignorance of physical reality, however, I’m cautious: this is just my best guess!

MV: Interesting. You note that you see no reason to believe that such systems would have a pleasure-pain axis. But what about the argument that pain has proven exceptionally adaptive over the course of biological evolution, and might thus plausibly prove adaptive in future forms of evolution as well (assuming things won’t necessarily be run according to civilized values)? 

DP: Currently, I can’t see any reason to suppose hedonic tone (or the taste of garlic) could be instantiated in inorganic quantum computers. If (a big “if”) the quantum-theoretic version of non-materialist physicalism is true, then subjectively it’s like something to be an inorganic quantum computer, just as it’s like something subjectively to be superfluid helium — a nonbiological macro-quale. But out of the zillions of state-spaces of experience, why expect the state-space of phenomenally-bound experience that inorganic quantum computers hypothetically support will include hedonic tone? My guess is that futuristic quantum computers will instantiate qualia for which humans have no name nor conception and with no counterpart in biological minds.

All this is very speculative! It’s an intuition, not a rigorous argument.

MV: Fair enough. What then is your view of hypothetical future computers built from biological neurons?

DP: Artificial organic neuronal networks are perfectly feasible. Unlike silicon-based “neural networks” — a misnomer in my view — certain kinds of artificial organic neuronal networks could indeed suffer. Consider the reckless development of “mini-brains”.

MV: Yeah, it should be uncontroversial that such developments entail serious risks.

Okay, David. What you have said here certainly provides much food for thought. Thanks a lot for patiently exploring these issues with me, and not least for all your work and your dedication to reducing the suffering of all sentient beings.

DP: Thank you, Magnus. You’re very kind. May I just add a recommendation? Anyone who hasn’t yet done so should read your superb Suffering-Focused Ethics (2020).

Consciousness – Orthogonal or Crucial?

The following is an excerpt from my book Reflections on Intelligence (2016/2020).

 

A question often considered open, sometimes even irrelevant, when it comes to “AGIs” and “superintelligences” is whether such entities would be conscious. Here is Nick Bostrom expressing such a sentiment:

By a “superintelligence” we mean an intellect that is much smarter than the best human brains in practically every field, including scientific creativity, general wisdom and social skills. This definition leaves open how the superintelligence is implemented: it could be a digital computer, an ensemble of networked computers, cultured cortical tissue or what have you. It also leaves open whether the superintelligence is conscious and has subjective experiences.

(Bostrom, 2012, “Definition of ‘superintelligence’”)

This is false, however. On no meaningful definition of “more capable than the best human brains in practically every field, including scientific creativity, general wisdom, and social skills” can the question of consciousness be considered irrelevant. This is like defining a “superintelligence” as an entity “smarter” than any human, and to then claim that this definition leaves open whether such an entity can read natural language or perform mathematical calculations. Consciousness is integral to virtually everything we do and excel at, and thus if an entity is not conscious, it cannot possibly outperform the best humans “in practically every field”. Especially not in “scientific creativity, general wisdom, and social skills”. Let us look at these three in turn.

Social Skills

Good social skills depend on an ability to understand others. And in order to understand other people, we have to simulate what it is like to be them. Fortunately, this comes quite naturally to most of us. We know what it is like to consciously experience emotions such as sadness, fear, and joy directly, and this enables us to understand where people are coming from when they report and act on these emotions.

Consider the following example: without knowing anything about a stranger you observe on the street, you can roughly know how that person would feel and react if they suddenly, by the snap of a finger, had no clothes on right there on the street. Embarrassment, distress, wanting to cover up and get away from the situation are almost certain to be the reaction of any randomly selected person. We know this, not because we have read about it, but because of our immediate simulations of the minds of others – one of the main things our big brains evolved to do. This is what enables us to understand the minds of other people, and hence without running this conscious simulation of the minds of others, one will have no chance of gaining good social skills and interpersonal understanding.

But couldn’t a computer just simulate people’s brains and then understand them without being conscious? Is the consciousness bit really relevant here?

Yes, consciousness is relevant. At the very least, it is relevant for us. Consider, for instance, the job of a therapist, or indeed the “job” of any person who attempts to listen to another person in a deep conversation. When we tell someone about our own state or situation, it matters deeply to us that the listener actually understands what we are saying. A listener who merely pretends to feel and understand would be no good. Indeed, this would be worse than no good, as such a “listener” would then essentially be lying and deceiving in a most insensitive way, in every sense of the word.

Frustrated Human: “Do you actually know the feeling I’m talking about here? Do you even know the difference between joy and hopeless despair?”

Unconscious liar: “Yes.”

Whether someone is actually feeling us when we tell them something matters to us, especially when it comes to our willingness to share our perspectives, and hence it matters for “social skills”. An unconscious entity cannot have better social skills than “the best human brains” because it would lack the very essence of social skills: truly feeling and understanding others. Without a conscious mind there is no way to understand what it is like to have such a mind.

General Wisdom

Given how relevant social skills are for general wisdom, and given the relevance of consciousness for social skills, the claim that consciousness is irrelevant to general wisdom should already stand in serious doubt at this point.

Yet rather than restricting our focus to “general wisdom”, let us consider ethics in its entirety, which, broadly construed at least, includes any relevant sense of “general wisdom”. For in order to reason about ethics, one must be able to consider and evaluate questions like the following:

Can certain forms of suffering be outweighed by a certain amount of happiness?

Does the nature of the experience of suffering in some sense demand that reducing suffering is given greater moral priority than increasing happiness (for the already happy)?

Can realist normative claims be made on the basis of the properties of such experiences?

One has to be conscious to answer such questions. That is, one must know what such experiences are like in order to understand their experiential properties and significance. Knowing what terms like “suffering” and “happiness” refer to – i.e. knowing what the actual experiences of suffering and happiness are like – is as crucial to ethics as numbers are to mathematics.

The same point holds true about other areas of philosophy that bear on wisdom, such as the philosophy of mind: without knowing what it is like to have a conscious mind, one cannot contribute to the discussion about what it is like to have one and what the nature of consciousness is. Indeed, an unconscious entity has no idea about what the issue is even about in the first place.

So both in ethics and in the philosophy of mind, an unconscious entity would be less than clueless about the deep questions at hand. If an entity not only fails to surpass humans in this area, but fails to even have the slightest clue about what we are talking about, it hardly surpasses the best human brains in practically every field. After all, these questions are also relevant to many other fields, ranging from questions in psychology to questions concerning the core foundations of knowledge.

Experiencing and reasoning about consciousness is a most essential part of “human abilities”, and hence an entity that cannot do this cannot be claimed to surpass humans in the most important, much less all, human abilities.

Scientific Creativity

The third and final ability mentioned above that an unconscious entity can supposedly surpass humans in is scientific creativity. Yet scientific creativity must relate to all fields of knowledge, including the science of the conscious mind itself. This is also a part of the natural world, and a most relevant one at that.

Experiencing and accurately reporting what a given state of consciousness is like is essential for the science of mind, yet an unconscious entity obviously cannot do such a thing, as there is no experience it can report from. It cannot display any scientific creativity, or even produce mere observations, in this most important science. Again, the most it can do is produce lies – the very anti-matter of science.

 

On Insects and Lexicality

“Their experiences may be more simple than ours, but are they less intense? Perhaps a caterpillar’s primitive pain when squashed is greater than our more sophisticated sufferings.”

— Richard Ryder, Painism: A Modern Morality, p. 64.

 

Many people, myself included, find it plausible that suffering of a certain intensity, such as torture, carries greater moral significance than any amount of mild suffering. One may be tempted to think that views of this kind imply we should primarily prioritize the beings most likely to experience these “lexically worse” states of suffering (LWS) — presumably beings with large brains.* By extension, one may think such views will generally imply little priority to beings with small, less complex brains, such as insects. (Which is probably also a view we would intuitively like to embrace, given the inconvenience of the alternative.) 

Yet while perhaps intuitive, I do not think this conclusion follows. The main argument against it, in my view, is that we should maintain a non-trivial probability that beings with small brains, such as insects, indeed can experience LWS (regardless of how we define these states). After all, on what grounds can we confidently maintain they cannot?

And if we then assume an expected value framework, and multiply the large number of insects by a non-trivial probability of them being able to experience LWS, we find that, in terms of presently existing beings, the largest amount of LWS in expectation may well be found in small beings such as insects.


* It should be noted in this context, though, that many humans ostensibly cannot feel (at least physical) pain, whereas many beings with smaller brains show every sign of having this capacity, which suggests brain size is a poor proxy for the ability to experience pain, let alone the ability to experience LWS, and that genetic variation in certain pain-modulating genes may well be a more important factor.


More literature

On insects:

The Importance of Insect Suffering
Reducing Suffering Amongst Invertebrates Such As Insects
Do Bugs Feel Pain?
How to Avoid Hurting Insects
The Moral Importance of Invertebrates Such as Insects

On Lexicality:

Value Lexicality
Lexical views without abrupt breaks
Clarifying lexical thresholds
Many-valued logic as a reply to sequence arguments in value theory

Physics Is Also Qualia

In this post, I seek to clarify what I consider to be some common confusions about consciousness and “physics” stemming from a failure to distinguish clearly between ontological and epistemological senses of “physics”.

Clarifying Terms

Two senses of the word “physics” are worth distinguishing. There is physics in an ontological sense: roughly speaking, the spatio-temporal(-seeming) world that in many ways conforms well to our best physical theories. And then there is physics in an epistemological sense: a certain class of models we have of this world, the science of physics.

“Physics” in this latter, epistemological sense can be further divided into 1) the physical models we have in our minds, versus 2) the models we have external to our minds, such as in our physics textbooks and computer simulations. Yet it is worth noting that, to the extent we ourselves have any knowledge of the models in our books and simulations, we only have this knowledge by representing it in our minds. Thus, ultimately, all the knowledge of physical models we have, as subjects, is knowledge of the first kind: as appearances in our minds.*

In light of these very different senses of the term “physics”, it is clear that the claim that “physics is also qualia” can be understood in two very different ways: 1) in the sense that the physical world, in the ontological sense, is qualia, or “phenomenal”, and 2) that our models of physics are qualia, i.e. that our models of physics are certain patterns of consciousness. The first of these two claims is surely the most controversial one, and I shall not defend it here; I explore it here and here.

Instead, I shall here focus on the latter claim. My aim is not really to defend it, as I already briefly did that above: all the knowledge of physics we have, as subjects, ultimately appears as experiential patterns in our minds. (Although talk of the phenomenology of, say, operations in Hilbert spaces admittedly is rare.) I take this to be obvious, and hit an impasse with anyone who disagrees. My aim here is rather to clarify some confusions that arise due to a lack of clarity about this, and due to conflations of the two senses of “physics” described above.

The Problem of Reduction: Epistemological or Ontological?

I find it worth quoting the following excerpt from a Big Think interview with Sam Harris. Not because there is anything atypical about what Harris says, but rather because I think he here clearly illustrates the prevailing lack of clarity about the distinction between epistemology and ontology in relation to “the physical”.

If there’s an experiential internal qualitative dimension to any physical system then that is consciousness. And we can’t reduce the experiential side to talk of information processing and neurotransmitters and states of the brain […]. Someone like Francis Crick said famously you’re nothing but a pack of neurons. And that misses the fact that half of the reality we’re talking about is the qualitative experiential side. So when you’re trying to study human consciousness, for instance, by looking at states of the brain, all you can do is correlate experiential changes with changes in brain states. But no matter how tight these correlations become that never gives you license to throw out the first person experiential side. That would be analogous to saying that if you just flipped a coin long enough you would realize it had only one side. And now it’s true you can be committed to talking about just one side. You can say that heads being up is just a case of tails being down. But that doesn’t actually reduce one side of reality to the other.

Especially worth resting on here is the statement “half of the reality we’re talking about is the qualitative experiential side.” Yet is this “half of reality” an “ontological half” or an “epistemological half”? That is, is there a half of reality out there that is part phenomenal, and part “non-phenomenal” — perhaps “inertly physical”? Or are we rather talking about two different phenomenal descriptions of the same thing, respectively 1) physico-mathematical models of the mind-brain (and these models, again, are also qualia, i.e. patterns of consciousness), and 2) all other phenomenal descriptions, i.e. those drawing on the countless other experiential modalities we can currently conceive of — emotions, sounds, colors, etc. — as well as those we can’t? I suggest we are really talking about two different descriptions of the same thing.

A similar question can be raised in relation to Harris’ claim that we cannot “reduce one side of reality to the other.” Is the reduction in question, or rather failure of reduction, an ontological or an epistemological one? If it is ontological, then it is unclear what this means. Is it that one side of reality cannot “be” the other? This does not appear to be Harris’ view, even if he does tacitly buy into ontologically distinct sides (as opposed to descriptions) of reality in the first place.

Yet if the failure of reduction is epistemological, then there is in fact little unusual about it, as failures of epistemological reduction, or reductions from one model to another, are found everywhere in science. In the abstract sciences, for example, one axiomatic system does not necessarily reduce to another; indeed, we can readily create different axiomatic systems that not only fail to reduce to each other yet which actively contradict each other. And hence we cannot derive all of mathematics, broadly construed, from a single axiomatic system.

Similarly, in the empirical sciences, economics does not “reduce to” quantum physics. One may object that economics does reduce to quantum physics in principle, yet it should then be noted that 1) the term “in principle” does an enormous amount of work here, arguably about as much as it would have to do in the claim that “quantum physics can explain consciousness in principle” — after all, physics and economics invoke very different models and experiential modalities (economic theories are often qualitative in nature, and some prominent economists have even argued they are primarily so). And 2) a serious case can be made against the claim that even all the basic laws found in chemistry, the closest neighbor of physics, can be derived from fundamental physical theories, even in principle (see e.g. Berofsky, 2012, chap. 8). This case does not rest on there being something mysterious going on between our transition from theories of physics to theories of chemistry, nor that new fundamental forces are implicated, but merely that our models in these respective fields contain elements not reducible, even in principle, to our models in other areas.

Thus, at the level of our minds, we can clearly construct many different mental models which we cannot reduce to each other, even in principle. Yet this merely says something about our models and epistemology. It hardly comprises a deep metaphysical mystery.

Denying the Reality of Consciousness

The fact that the world conforms, at least roughly, to description in “physical” terms seems to have led some people to deny that consciousness in general exists. Yet this, I submit, is a fallacy: the fact that we can model the world in one set of terms which describe certain of its properties does not imply that we cannot describe it in another set of terms that describe other properties truly there as well, even if we cannot derive one from the other.

By analogy, consider again physics and economics: we can take the exact same object of study — say, a human society — and describe aspects of it in physical terms (with models of thermodynamics, classical mechanics, electrodynamics, etc.), yet we cannot from any such description or set of descriptions meaningfully derive a description of the economics of this society. It would clearly be a fallacy to suggest that this implies facts of economics cannot exist.

Again, I think the confusion derives from conflating epistemology with ontology: “physics”, in the epistemological sense of “descriptions of the world in physico-mathematical terms”, appears to encompass “everything out there”, and hence, the reasoning goes, nothing else can exist out there. Of course, in one sense, this is true: if a description in physico-mathematical terms exhaustively describes everything out there, then there is indeed nothing more to be said about it — in physico-mathematical terms. Yet this says nothing about the properties of what is out there in other terms, as illustrated by the economics example above. (Another reason some people seem to deny the reality of consciousness, distinct from conflation of the epistemological and the ontological, is “denial due to fuzziness”, which I have addressed here.)

This relates, I think, to the fundamental Kantian insight on epistemology: we never experience the world “out there” directly, only our own models of it. And the fact that our physical model of the world — including, say, a physical model of the mind-brain of one’s best friend — does not entail other phenomenal modalities, such as emotions, by no means implies that the real, ontological object out there which our physical model reflects, such as our friend’s actual mind-brain, does not instantiate these things. That would be to confuse the map with the territory. (Our emotional model of our best friend does, of course, entail emotions, and it would be just as much of a fallacy to say that, since such emotional models say nothing about brains in physical terms, descriptions of the latter kind have no validity.)

Denials of this sort can have serious ethical consequences, not least since the most relevant aspects of consciousness, including suffering, fall outside descriptions of the world in purely physical terms. Thus, if we insist that only such physico-mathematical descriptions truly describe the world, we seem forced to conclude that suffering, along with everything else that plausibly has moral significance, does not truly exist. Which, in turn, can keep us from working toward a sophisticated understanding of these things, and from creating a better world accordingly.

 


* And for this reason, the answer to the question “how do you know you are conscious?” will ultimately be the same as the answer to the question “how do you know physics (i.e. physical models) exist?” — we experience these facts directly.

Thinking of Consciousness as Waves

First written: Dec 14, 2018, Last update: Jan 2, 2019.

 

How can we think about the relationship between the conscious and the physical? In this essay I wish to propose a way of thinking about it that might be fruitful and surprisingly intuitive, namely to think of consciousness as waves.

The idea is quite simple: one kind of conscious experience corresponds to, or rather conforms to description in terms of, one kind of wave. And by combining different kinds of waves, we can obtain an experience with many different properties in one.

It should be noted that I in this post merely refer to waves in an abstract sense to illustrate a general point. That is, I do not refer to electromagnetic waves in particular (as some theories of consciousness do), nor to quantum waves (as other theories do), nor to any other particular kind of wave (such as Selen Atasoy’s so-called connectome-specific harmonic waves*). The point here is not what kind of wave, or indeed which physical state in general, that mediates different states of consciousness. The point is merely to devise a metaphor that can render intuitive the seemingly unintuitive, namely: how can we get something complex and multifaceted from something very simple without having anything seemingly spooky or strange, such as strong emergence, in between? In particular, how can we say that brains mediate conscious experience without saying that, say, electrons mediate conscious experience? I believe thinking about consciousness in terms of waves can help dissolve this confusion. 

The magic of waves is that we can produce (or to an arbitrary level of precision approximate) any kind of complex, multifaceted wave by adding simple sine waves together.

 

Image result for waves sine
Sine waves with different frequencies.

 

In this way, it is possible, for instance, to decompose any recorded song — itself a complex, multifaceted wave — into simple, tedious-sounding sine waves. Each resulting sine wave can be said to comprise an aspect of the song, yet not in any recognizable way. The whole song is in fact a sum of such waves, not in a strange way that implies strong emergence, but merely in a complicated, composite way.

Another way to think about waves that can help us think more clearly about emergent complexity is to think of a wave that is very small in both amplitude and duration. If this were a sound wave, it would be an extremely short-lived, extremely low-volume sound. On a visual representation of an entire song file, this sound would look more akin to a dot than a wave.

 

Image result for a point math
A dot.

 

And such simple sound waves can also be put together so as to create a song (for instance, one can take the sine waves obtained by decomposing a song and then chop them into smaller bits and decrease their amplitude). It will just, to make a song, take a very great number of such small waves superimposed (if the song is to be loud enough to hear) and in succession (if the song is to last for more than a split-second).

 

The deeper point here is that waves are waves, no matter how small or simple, large or complex. Yet not all waves comprise what we would recognize as music. Similarly, even if all physical states are phenomenal in the broadest sense, this does not imply that they are conscious in the sense of being an ordered, multifaceted whole. Unfortunately, we do not as yet have good, analogous terms for “sound” and “music” in the phenomenal realm — perhaps we could use “phenomenality” and “consciousness”, respectively?

The problem is indeed that we are limited by language, in that the word “conscious” usually only connotes an ordered, composite mind rather than the property of phenomenality in the most general sense. Consequently, if we think all that exists is either music or non-sound, metaphorically speaking, we are bound to be confused. But if we instead expand our vocabulary, and thereby expand our allowed ways of thinking, our confusion can, I think, be readily dissolved. If we think of the phenomenality of the simplest physical systems as being nothing like consciousness in the usual sense of a composite mind but rather as a state of hyper-crude phenomenality — i.e. “phenomenal noise” that is nothing like a song but more akin to a low, short-lived sound, and yet unimaginably more crude still — then the problem of consciousness, as commonly (mis)conceived, seems to become a lot less confusing.**

Avoiding Confusion Due to Fuzziness

A more specific point of confusion the wave metaphor can help us dissolve is the notion that consciousness is so fuzzy a category that it in fact does not really exist, just like tables and chairs do not really exist. As I have argued elsewhere, I think this is a non sequitur. The fact that the categories of tables and chairs are themselves fuzzy does not imply that the physical properties of the objects to which we refer with these labels are inexact, let alone non-existent. The objects have the physical properties they have regardless of how we label them. Or, to continue the analogy to waves above, and songs in particular: although there is ambiguity about what counts as a song, this does not imply that we cannot speak in precise, factual terms about the properties of a given song — for instance, whether a given song contains a 440 Hz tone.

Similarly, the fact that consciousness, as in “an ordered, composite mind”, is a fuzzy category (after all, what counts as ordered? Do psychotic states? Fleeting dreams?) does not imply that any given phenomenal state we refer to with this term does not have exact and clearly identifiable phenomenal properties — e.g. an experience of the color red or the sensation of fear; properties that exist regardless of how outside observers choose to label them.

And although our labels for categorizing particular phenomenal states themselves tend to be fuzzy to some extent — e.g. which part of the spectrum below counts as red? — this does not imply that we cannot distinguish between different states, nor that we cannot draw any clear boundaries. For instance, we can clearly distinguish between the blue and the red zones respectively on the illustration below despite its gradation.

 

Image result for range of color
A linear representation of the visible light spectrum with wavelengths in nanometers.

 

Just as we can point toward a confined range of wavelengths which induce an experience of (some kind of) red in most people upon hitting their retinas, we can also, in principle, point to a range of physical states that mediate specific phenomenal states. This includes the phenomenal states we call suffering, with the fuzziness of what counts as suffering contained within and near the bounds of this range, while the physical states outside this range, especially those far away, do not mediate suffering, cf. the non-red range in the illustration above.

Thus, by analogy to how we can have precise descriptions of the properties of a song, even as an exact definition of what counts as a song escapes us, there is no reason why we should not be able to speak in factual and precise terms about the phenomenal aspects of a mind and its physical signatures, including the “red range” of wavelengths that comprise phenomenal suffering, metaphorically speaking. And a sophisticated understanding of this notional range is indeed of paramount importance for the project of reducing suffering.


* Note that these seemingly different kinds of waves and theories of consciousness can be identical, since connectome-specific harmonic waves could turn out to be coherent waves in the electromagnetic quantum field, as would seem suggested by a hypothesis known as quantum brain dynamics (I do not necessarily endorse this particular hypothesis).

** Another useful analogy for thinking more clearly about the seemingly crazy notion that “everything is conscious” — or rather: phenomenal — is to think about the question, Is everything light? For in a highly non-standard sense, everything is indeed “light”, in that electromagnetic waves permeate the universe in the form of cosmic background radiation, although everything is not permeated by light in the usual sense of visible electromagnetic radiation (wavelengths around 400–700 nm). We may thus think of consciousness as analogous to visible light (they can also both be more or less intense and have various nuances), and electromagnetic radiation as analogous to phenomenality — the more general phenomenon that encompasses the specific one.

 

“The Physical” and Consciousness: One World Conforming to Different Descriptions

My aim in this essay is to briefly explain a crucial aspect of David Pearce‘s physicalist idealist worldview. In particular, I seek to explain how a view can be both “idealist” and “physicalist”, yet still be a “property monist” view.

Pearce himself describes his view in the following way:

“Physicalistic idealism” is the non-materialist physicalist claim that reality is fundamentally experiential and that the natural world is exhaustively described by the equations of physics and their solutions […]

So Pearce’s view is a monist, idealist view: reality is fundamentally experiential. And this reality also conforms to description in physical terms. Pearce is careful, however, to distinguish this view from panpsychism, which Pearce, in contrast to his own idealist view, considers a property dualist view:

“Panpsychism” is the doctrine that the world’s fundamental physical stuff also has primitive experiential properties. Unlike the physicalistic idealism explored here, panpsychism doesn’t claim that the world’s fundamental physical stuff is experiential. Panpsychism is best treated as a form of property-dualism.

How, one may wonder, is Pearce’s view different from panpsychism, and from property dualist views more generally? This is something I myself have struggled a lot to understand, and inquired him about repeatedly. And my understanding is the following: according to Pearce, there is only consciousness, and its dynamics conform to physical description. Property dualist views, in contrast, view the world as having two properties: the stuff of the world has insentient physical properties to which separate, experiential properties are somehow attached.

Pearce’s view makes no such division. Instead, on Pearce’s view, description in physical terms merely constitutes a particular (phenomenal) mode of description that (phenomenal) reality conforms to. So to the extent there is a dualism here, it is epistemological, not ontological.

The Many Properties of Your Right Ear

For an analogy that might help explain this point better, consider your right ear. What properties does it have? Setting aside the question concerning its intrinsic nature, it is clear that you can model it in various ways. One way is to touch it with your fingers, whereby you model it via your faculties of tactile sensation (or in neuroanatomical terms: with neurons in your parietal lobe). You may also represent your ear via auditory sensations, for example by hitting it and noticing what kind of sound it makes (a sensation mediated by the temporal lobe). Another way, perhaps the clearest and most practical way for beings like us, is to model it in terms of visual experience: to look at your right ear in the mirror, or perhaps simply imagine it, and thereby have a visual sensation that represents it (mediated by the occipital lobe).

[For most of us, these different forms of modeling are almost impossible to keep separate, as our touching our ears automatically induces a visual model of them as well, and vice versa: a visual model of an ear will often be accompanied by a sense of what it would be like to touch it. Yet one can in fact come a surprisingly long way toward being able to “unbind” these sensations with a bit of practice. This meditation and this one both provide a good exercise in detaching one’s tactile sense of one’s hands from one’s visual model of them. This one goes even further, as it climaxes with a near-total dissolution of our automatic binding of different modes of experience into an ordered whole.]

Now, we may ask: which of these modes of modeling constitute the modeling we call “physical”? And the answer is arguably all of them, as they all relate to the manifestly external (“physical”) world. This is unlike, say, things that are manifestly internal, such as emotions and thoughts, which we do not tend to consider “physical” in this same way, although all our sensations are, of course, equally internal to our mind-brain.

“The physical” is in many ways a poorly defined folk term, and physics itself is not exempt from this ambiguity. For instance, what phenomenal mode does the field of physics draw upon? Well, it is certainly more than just the phenomenology of equations (to the extent this can be considered a separate mode of experience). It also, in close connection with how most of us think about equations, draws heavily on visuospatial modes of experience (I once carefully went through a physics textbook that covered virtually all of undergraduate level physics with the explicit purpose of checking whether it all conformed to such description, and I found that it did). And we can, of course, also describe your right ear in “physics” terms, such as by measuring and representing its temperature, its spatial coordinates, its topology, etc. This would give us even more models of your right ear.

 

The deeper point here is that the same thing can conform to description in different terms, and the existence of such a multitude of valid descriptions does not imply that the thing described itself has a multitude of intrinsic properties. In fact, none of the modes of modeling an ear mentioned above say anything about the intrinsic properties of the ear; they only relate to its reflection, in the broadest sense.

And this is where some people will object: why believe in any intrinsic properties? Indeed, why believe in anything but the physical, “reflective”, (purportedly) non-phenomenal properties described above?

To me, as well as to David Pearce (and Galen Strawson and many others), this latter claim is self-undermining and senseless, like a person reading from a book who claims that the paper of the book they are reading from does not exist, only the text does. All these modes of modeling mentioned above, including all that we deem knowledge of “the physical” are phenomenal. The science we call “physics” is itself, to the extent it is known by anyone, found in consciousness. It is a particular mode of phenomenal modeling of the world, and thus to deny the existence of the phenomenal is also to deny the existence of our knowledge of “physics”.

Indeed, our knowledge of physics and “the physical” attests to this fact as clearly as it attests to anything: consciousness exists. It is a separate question, then, exactly how the varieties of conscious experience relate to descriptions of the world in physical terms, as well as what the intrinsic nature of the stuff of the world is, to the extent it has any. Yet by all appearances, it seems that minds such as our own conform to physical description in terms of what we recognize as brains, and, as with the example of your right ear, such a physical description can take many forms: a visual representation of a mind-brain, what it is like to touch a mind-brain, the number of neurons it has, its temperature, etc.

These are different, yet valid ways of describing aspects of our mind-brains. Yet like the descriptions of different aspects of an ear mentioned above, these “physical” descriptions, while all perfectly valid, still do not tell us anything about the intrinsic nature of the mind-brain. And according to David Pearce, the intrinsic nature of that which we (validly) describe in physical terms as “your brain” is your conscious mind itself. The apparent multitude of aspects of that which we recognize as “brains” and “ears” are just different modes of conscious modeling of an intrinsically monist, i.e. experiential, reality.

 


The view of consciousness explored here may seem counter-intuitive, yet I have argued elsewhere that using waves as a metaphor can help render it less unintuitive, perhaps even positively intuitive.

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