Is quantum mechanics relevant to the philosophy of mind (and the other way around)?

6a00d8341bf7f753ef01910260a3e7970cby Quentin Ruyant

There have been speculations on a possible link between quantum mechanics and the mind almost since the early elaboration of quantum theory (including by well known physicists, such as Wigner, Bohr and Pauli). Yet despite a few proposals (e.g. from Stapp, Penrose, Eccles [1]) what we could dub “quantum mind hypothesis” are often readily dismissed as irrelevant and are seldom discussed in contemporary philosophy of mind. My aim in this article is to defend the relevance of this type of approach.

For the purpose of this discussion it is useful to distinguish two different theses regarding the putative links between quantum mechanics and the mind:

  1. The mind is relevant in interpreting quantum mechanics
  2. Quantum mechanics is relevant in the philosophy of mind

Of course the two theses are not necessarily construed as independent by the proponents of quantum-mind hypothesis. One could argue that the mind is relevant in interpreting quantum mechanics, precisely for the same reasons that quantum mechanics is relevant in the philosophy of mind. This is actually what I will argue here (or at least that it is a promising hypothesis that should be pursued). However, the two theses face different kinds of objections and need to be distinguished.

Is consciousness a biological problem?

Quite logically, I will first tackle the second one: the idea that quantum mechanics could help us explain consciousness. Such claim is sometimes dismissed on the ground that the problem of understanding consciousness is a biological problem, not a physical one. Let me clarify a bit: by “biological/physical problem” I understand: a problem which is better informed by biology/physics, not necessarily a purely scientific (as opposed to philosophical) problem. Quantum mechanics, it is said, is only relevant at very small scales of reality, while conscious organisms are biological organisms, typically found at a macroscopic level, where quantum effects manifest themselves as mere noise. Besides, it is said, randomness is not a proper substitute for free-will, so quantum mechanics wouldn’t help anyway. Therefore quantum mechanics is irrelevant to philosophy of mind.

First, let us observe that typical quantum effects are not necessarily foreign to biology, as illustrated by the burgeoning field of quantum biology. Nor are they in principle confined to the microscopic level — this is the heart of the measurement problem, as illustrated by the famous Schrödinger’s cat thought experiment. Quantum effects such as entanglement also help explain macroscopically observable properties, such as heat capacities or magnetic susceptibilities [2]. It is generally assumed that decoherence precludes the observability of quantum effects on macroscopic objects, but as Zurek et al. note, decoherence is more a heuristic tool to be applied on a case by case basis than a generic consequence of the theory [3]. Finally, quantum entanglement is hard to measure on complex systems. The idea that no quantum effect exists at all on our scale is thus neither empirically nor theoretically grounded. At most we can say that no quantum effect is detectable in common physical objects whose behavior can be accurately described using Newtonian mechanics alone, such as tables and chairs, but of course these are not the sort of conscious objects we are interested in (unless, of course, you think that biological phenomena can be explained with Newtonian mechanics alone).

However, my main contention concerns the idea that the problem of consciousness is a biological problem. Let us follow Chalmers in distinguishing the “easy problems” of consciousness from the “hard problem.” The easy problems concern everything that is scientifically tractable from a third person perspective — how do we discriminate and integrate information, etc. that is, all the cognitive aspects of consciousness. These (not so easy) problems are undeniably biological or psychological. The “hard problem” concerns the phenomenal aspect of consciousness, the subjective first-person “what it’s like” to be conscious. And this question, Chalmers argues, is not scientifically tractable: it is a metaphysical problem.

Metaphysics addresses the most fundamental aspects of reality and arguably the phenomenal aspect of consciousness is one of them. Now, if there is a branch of science which more closely resembles metaphysics in its specific interest for the fundamental aspects of reality, it is physics — not biology. Physics and metaphysics overlap in many respects (just consider the wild speculations about a mathematical universe advanced by physicists such as Tegmark [4]) and there is probably a continuum between the two. On the contrary, a contribution of biology to fundamental metaphysical issues seems to me rather implausible. I could be wrong (and Chalmers could be wrong in thinking that phenomenal aspects of consciousness are metaphysical), but I contend that the hard problem of consciousness, if it exists, is not a biological problem, but a physical one: it is just too fundamental a problem to be addressed from a biological perspective. Note that I don’t mean to deny that there are relations between phenomenal and psychological aspects, in the sense that certain cognitive states are correlated with specific phenomenal aspects, but explaining such correlations is distinct from explaining why there are phenomenal aspects to begin with.

Of course, no metaphysician denies that physics is of interest in the philosophy of mind. Kim’s causal exclusion argument involves the principle of “physical closure.” The argument precisely addresses the problem of the relations between the physical and the mental [5]. What some metaphysicians apparently deny is that quantum physics or any actual physics is of particular interest for such issues: for these authors metaphysics can still produce interesting insights about the physical “in general,” that is, whatever actual physics says. They seem to assume that the physical “in general” poses no important problem of interpretation apart from the well entrenched problems of classical metaphysics.

It seems to me that there is no such thing as “the physical in general, whatever actual physics says”: our conception of the physical changes with our physics. There is no point in reasoning on the physical without taking into account what our best current physics says about it. And our best current physics is quantum mechanics (quantum field theory to be precise). For this reason I think, following Ladyman, Ross and Spurrett [6], that metaphysicians should be informed by our best physics rather than work on a dated conception of the physical, or, as they say provocatively, on “A-level chemistry.” (Ladyman, Ross and Spurrett note that some of Kim’s central arguments rely on conceptions of the physical that are no longer accepted by physicists. The same goes, I would say, of thought experiments involving clones and mind duplication: the no-cloning theorem in quantum mechanics precludes the possibility of such perfect physical duplication [7]).

I am not saying that all metaphysicians should be trained in contemporary physics to produce valuable work (Kim’s Mind in a Physical World is very valuable and important, in my opinion), but contemporary physics is definitely a place we should look at to address fundamental issues in the philosophy of mind. My overall impression is that this is hardly the case today, although such inputs are considered in Chalmers’ The Conscious Mind [8].

Does embracing a quantum mechanical view of the physical really change the perspective for the metaphysics of mind? At the very least metaphysical interpretations of the physical inspired by contemporary physics could open new avenues to be explored, and, perhaps, help make progress on important conundrums in the field, such as the problem of mental causation. It seems to me that there are no good reasons not to follow this path.

Is the mind foreign to the measurement problem?

Which leads us directly to the second point, i.e., the first thesis sketched above: that the mind is relevant in interpreting quantum mechanics. The idea was initially proposed by some physicists as a solution to the measurement problem — the problem of reconciling the theoretical structure of quantum mechanics, which describes non-local “superpositions of states,” with actual phenomena, where no superposition is ever observed. The theoretical structure does all the predictive job, so to speak (apart from the Born rule, which maps the structure with outcome probabilities [9]) and ultimately, the fact that no superposition exists for measured quantities is only ascertained by our conscious observation. Hence the idea that it is the mind which makes the wave-function “collapse.” Of course there are other, less anthropocentric theories, such as Bohm’s, Ghirardi-Rimini-Weber [10] or the infamous many-worlds interpretation [11].

The main type of objection against interpretations involving an observer, I would say, is that they seem too reminiscent of either 19th century Idealism or early 20th century neo-Kantian and phenomenalist views (which did strongly influence said physicists). These doctrines have declined in favor of a renewal of scientific realism in the course of the 20th century.

From a realist perspective, such interpretations seem to attribute a privileged ontological status to the human brain, which is increasingly not acceptable. Was there really no definite reality before life appeared on earth? Does the moon vanishes when no one is looking? All this seems barely good enough for mystics and new age gurus (there might be more sensible anti-realist interpretations, but let’s not quibble…) However, having previously rejected the idea that phenomenal aspects of consciousness are to be addressed by biology, all of this is easily defused: a privileged ontological status of human observers only makes sense for those who pretend that biology can inform deep metaphysical questions.

Let me be more specific and draw on an example. I suggested that phenomenal aspects of consciousness could eventually be explained under a proper interpretation of physics. A possible such explanation could take the form of panpsychism: the idea that, somehow, all matter is conscious. In fact, by distinguishing phenomenal aspects from cognitive aspects of consciousness and relegating the former to physics and the latter to biology or psychology, we would have something like panphenomenalism: the idea that all matter is “phenomenal.” Anyway, in the context of either panpsychism or panphenomenalism, granting a particular role to phenomenality in physics, say, in the collapse of the wave function, does not amount to granting a privileged ontological status to the brain.

Perhaps panpsychism is implausible, but panphenomenalism fares a bit better in my opinion. Obviously, tables and chairs are not conscious. Following panphenomenalism, what they lack is not phenomenality (which would be a feature of their fundamental constitution) but cognitive abilities. Phenomenality without memory, persistence, information integration and a capacity for world and self representation is simply not awareness, or not full awareness — it is at best being transiently aware of nothing identifiable, without the very possibility of knowing that one is or was aware,nothing close to consciousness. I would readily grant this feature to electrons if it could convincingly explain some relevant metaphysical issue.

Another frequent objection against panpsychism is the so-called combination problem: if phenomenal aspects are present in the microscopic constituents of reality, how is it that we have a unified phenomenal experience? I don’t have an answer to this question, but it is not specific to panpsychism (it is a version of the binding problem also found in computational theories of mind, for example). My guess is that it has something to do with a link between quantum entanglement and cognition, perhaps in line with Tononi’s integrated information theory [12], but this is pure speculation. In any case, quantum holism, if accepted, seems to provide a good basis to answer this [13], whatever quantum-mind theory we endorse.

At any rate, although I find it attractive, my goal is not to convince you that panphenomenalism is the one true theory of mind, but to illustrate the fact that one can make sense of an involvement of the mind in the interpretation of quantum mechanics without falling back into Idealism. And, of course, there are other alternatives too, such as Eccles’ dualism for example, or Stapp’s kind-of dual aspect theory, or perhaps some versions of neutral monism.

Another common objection to considering a role of the observer in the measurement problem is that it involves non-locality, which is at odds with Lorentz invariance in special relativity. This is actually a potential problem for most collapse interpretations of quantum mechanics (but apparently, GRW theory does not face it). However, invoking phenomenal aspects in a solution to the measurement problem does not necessarily involve an objective wave-function collapse: it could involve, say, a relational or a modal interpretation of quantum mechanics [14]. Which interpretation of quantum mechanics best fits our needs to account for phenomenal aspects depending on which theory of mind we endorse is precisely the kind of question which should be addressed in the philosophy of mind.

In sum, my goal is not to defend one or the other interpretation of quantum mechanics, nor to defend one or the other theory of mind, but rather to stress the relevance and potential fruitfulness of discussions relating these two domains of inquiry. The hard problem of consciousness and the measurement problem in quantum mechanics share a strong conceptual affinity: both concern the relations between physical structure and phenomenal aspects of reality, broadly construed. Either the world viewed from the mind, or the mind viewed from the world, if you like. This conceptual affinity should not be neglected on the ground of unfounded suspicions of Idealism or anti-realism or any other similar concern. The example of panphenomenalism above shows that a common treatment to both problems might be explored without presenting insurmountable obstacles, something worth pondering.

Yet, in spite of the conceptual affinity between these two central problems of philosophy, talk of quantum mechanics in the philosophy of mind is often brushed aside. At the same time, talk of consciousness and rational agents in, say, discussions on the many-worlds (or many-minds) interpretation of quantum mechanics is ubiquitous, and difficult to avoid. Both camps act as if important issues in the other camp were already settled. This is a strange situation. Aren’t we perhaps missing something by being too compartimentalized? One of the main roles of philosophy — and metaphysics in particular — is after all to provide a unified picture of the world. Is it inconceivable that some considerations in the philosophy of mind (or other areas of philosophy) might inform our interpretations of physics as much as the converse?

Is quantum mechanics useful at all?

To conclude, let me address a final worry that I have so far left aside: that quantum mechanics is of no help in explaining the mind at all. I don’t know about the debate concerning the relationship between free-will and randomness — except that randomness in quantum mechanics is closely tied to the measurement problem, and that what we mean by “randomness” is also up to interpretation. (Shouldn’t we say “unpredictability” instead? Or shall I suggest “physical privacy”?)

Besides, I do not claim that quantum mechanics can explain consciousness. My argument is more modest: the question of phenomenal aspects of consciousness should be addressed in relation to quantum mechanics, because only our best physics can inform such metaphysical questions, and because quantum effects are not necessarily confined to the microscopic realm. Moreover, it should be addressed in relation to the measurement problem, because they share conceptual affinities, and because the “threat” of Idealism is unfounded. All I claim is that a suitable metaphysical interpretation of quantum mechanics could eventually explain the metaphysical problem of consciousness.

Having said that, some features of quantum mechanics such as non-locality/holism or the no-cloning and the free-will theorem [15], could eventually help address some questions in the philosophy of mind, such as the binding problem or the problem of causal exclusion.

In light of this, quantum mechanics certainly deserves more consideration in the philosophy of mind. In my view, claiming that quantum effects reduce to “microscopic noise” simply disregards the epistemic depth of the measurement problem, just as claiming that the problem of consciousness is essentially biological disregards its ontological depth. These two “dogmas” of philosophy of mind are mutually reinforcing and we should reject them altogether if we want to make sense of consciousness as well as of quantum mechanics.


Quentin Ruyant is a PhD student in philosophy of science in Rennes, France and former engineer. He maintains a blog dedicated to the popularization of philosophy of science (in French)

[1] Quantum approaches to consciousness, Stanford Encyclopedia of Philosophy.

[2] Macroscopic entanglement witnesses.

[3] Deconstructing decoherence.

[4] Our mathematical universe;  and Why physicists are saying consciousness is a state of matter, like a solid, a liquid or a gas.

[5] See “The completeness of the physical,” in Mental causation, Stanford Encyclopedia of Philosophy.

[6] Every Thing Must Go: Metaphysics Naturalized.

[7] No-cloning theorem.

[8] The Conscious Mind: In Search of a Fundamental Theory.

[9] The Born rule.

[10] On collapse theories and the Ghirardini-Rimini-Weber model.

[11] See this recent essay by Sean Carroll about why the many-worlds interpretation of QM is not that crazy after all.

[12] Integrated information theory.

[13] See: Holism and nonseparability in physics, Stanford Encyclopedia of Philosophy.

[14] Modal interpretations of quantum mechanics and Relational quantum mechanics, Stanford Encyclopedia of Philosophy.

[15] Free will theorem.

200 thoughts on “Is quantum mechanics relevant to the philosophy of mind (and the other way around)?

  1. Hi Aaron,

    Since you take Massimo as someone who has dismantled the hard problem, let me paint what I see as a problem with Massimo’s view. I’m not sure you will agree.

    Massimo believes that were we able to simulate a human being (down to the last electron if necessary), then it is reasonable to suppose that such a simulation would behave as a human. As such, it would represent and manifest the same solutions for the ‘easy’ problems as we do. However, Massimo believes that such a simulated entity would not be conscious. To me, this means that Massimo implicitly believes that it is possible to solve the easy problems without solving the hard problem, and therefore that the hard problem is a distinct, real problem, in contradiction to his professed position that it isn’t.


  2. Hi Massimo,

    And my contention is that it has nothing whatsoever to do with p-zombies who, btw, are supposed to be physical, not virtual.

    I guess we’re not going to see eye to eye on that, at least not without a proper discussion (and probably not then).

    So, if I could just raise the point of your other objection to Chalmers, the hard problem. A simulated person would implement solutions to all the easy problems, exhibiting the same intelligent behaviours we do. But it would not implement a solution for the hard problem (actual consciousness). Doesn’t this mean that the hard problem is a real, distinct problem from the easy problems?


  3. It seems to e that the thisness of the hole is exhausted by the geometrical structure–describe the structure and you have it all. The point of Chalmers is that a physical structure doesn’t seem to exhaust everything.


  4. DM, I take biological naturalism – and indeed any reasonable theory of consciousness – to exclude the so-called hard problem. It isn’t a problem, it is simply Chalmers’ making up a “conceivable” (to him, to me it is nonsense on stilts) situation and than protesting that there must be a problem because materialist science can’t account for his imagination ran wild.

    Consider this: if I were to tell you that I can conceive of a squared circle, and then went to on complain that my ability to do so shows that there is something woefully lacking in mathematical theory, how would you react? That’s how I react to Chalmers, in my opinion a very good competitor for the title of most overrated philosopher living today.


  5. Coel – Sorry , but I cannot discuss these things here. The system is too difficult. I have no idea where this post will appear. I reckon Massimo could usefully set up a forum. Obviously I don’t agree with what you said earlier, in response to me, but we’ll have to leave it. I’ll just say one thing. Metaphysics can deal with consciousness just fine. This is not to say, or course, that all of its practitioners can. To back this up I’d have to refer you elsewhere, however, which would be spam. It is worth noting, however, that Chalmers’ problem does not arise for Nagarjuna and Lao Tsu.

    Unless you want to pursue the issue elsewhere, though, I think we’ll have to leave it. Nice to chat.


  6. Massimo,
    Maybe the challenge with Chalmers’ zombie argument is to explain why it is “nonsense on stilts”, i.e. why a zombie could not possibly exist?
    Chalmers probably fails to show that zombies are actually possible, but the fact that they seem intuitively conceivable to many people at least indicated that the way those people conceive the physical realm does not account for the “what it’s like” aspect.


  7. Quentin, I’m sorry, but the burden of proof seems to me to be on Chalmers: he needs to tell us why his conceivability should be taken as a serious guide to fundamental problems with our metaphysics. In my mind p-zombies are nonsense on stilts for the simple reason that what we know about consciousness so far implies their physical impossibility. The fact that they may be logically possible is entirely irrelevant, since all sorts of things are logical possible and yet not physically instantiated, without this somehow creating a problem of any sort, let alone a hard one.


  8. To be precise, a quantum system can be simulated with a classical system with exponential slowdown (one of the reason we are trying to build quantum computers), which means that you could perhaps simulate a person with a classcal computer, but you’ll need an exponentailly increasing amount of ressources to do it in real time (if you want to interact with the simulation for example). I suppose you would reach the size of the universe in needed ressources pretty soon.


  9. of course, we would not appeal to quantum mechanics to explain why a bridge broke, or what have you, because the explanandum clearly belongs to classical physics, and we know by induction that such systems do not manifest quantum effects.

    Not true. Bridges have fallen because the steel cables or rivets were not strong enough, and the strength of that type of steel was explained by quantum mechanics. Classical physics does not explain the strength of steel.

    The same error underlies your discussion of whether quantum physics affects the mind. There is no possibility of classical physics explaining the brain. Of course QP will be essential for a deeper understanding of the brain.


  10. At least the fact that they are logically conceivable, but seems physically impossible, indicates a gap in our understanding: we do not know why they are physically impossible.

    No problem so far, we don’t understand everything and we don’t understand consciousness, but Chalmers argument (or the way I understand it) is: you can add any additional structure or physical configuration to your representation and that won’t change, it’s only structure, not experience, so zombies will always be logically conceivable no matter the complexity of our physical representation of human beings.

    Maybe the burden is on his side to show that no matter what configuration you add, the gap will remain, but frankly, I don’t see how adding more structure to some physical configuration could allow the emergence of phenomenal aspects out of nothing.


  11. I fail to see the gap to which you refer. You (and Chalmers) seem to think that unless something is logically necessary (or impossible) then we are missing part of the picture. I don’t see why that follows at all. We know that the space of logical possibilities is much larger than that of physical and contingent possibilities. So? The real problem, of course, is that we haven’t solved the so-called “easy” problems, which means that there is a gap in our understanding of consciousness. But that gap need not be metaphysically troublesome, as Chalmers suggests it is (remember, he gets dualism out of his thought experiment).


  12. Quentin Ruyant: “The hard problem of consciousness and the measurement problem in quantum mechanics share a strong conceptual affinity: …”

    I have only one thing to say about this; 99.99…99…% of quantum ‘measuring’ devices in ‘this’ universe are not humanly made, that is, quantum particles are measuring among one another all the time.

    Quentin Ruyant: “On the contrary, a contribution of biology to fundamental metaphysical issues seems to me rather implausible.”

    I disagree with this statement totally. This universe can be described with three parts.
    1. A (the) base: a set of physics laws (including quantum principle), and this is linked to the metaphysical sphere.
    2. A (the) manifestation: this ‘universe’ (galaxies, Earth and lives). And, the life is the highest (most complicated) manifestation.
    3. A (the) process: which bridges the base and the manifestation.

    Thus, any ‘direct’ correlation between quantum effect and mind (the highest of highest manifestation) might not be there. So, {Quentin Ruyant: “… the question of phenomenal aspects of consciousness should be addressed in relation to quantum mechanics, because ….”} should not be the case. Yet, everything (including mind) in the manifestation should and must have a corresponding partner (seed) in the ‘base’. And, there are ways to find out this correspondence. And, the first task is to ‘identify’ the thing clearly (clearly, …, clearly) that is under our investigation; that is, a ‘perfect’ definition of that thing.

    There is no right or wrong on any ‘definition’ but has good or bad distinction. A bad definition will often lead to wrong conclusion and simply be useless. A bad definition can give a wrong ‘scope’ which can exclude the ‘essence’ of the topic from this wrongly defined scope. Thus, a ‘bad’ definition is destined of not being able to reach the correct answer for the issue. For example, if we define ‘consciousness’ as brain-based or human-like, this definition automatically excludes the entire ‘base’; that is, there is no chance of any kind to link the issue to the base. Well, instead of just talking, I will just show the steps.

    What is ‘mind’? Instead of giving a clearly definition, I will just discuss its three attributes (while it could have many more attributes).
    a. It produces ‘intelligence’.
    b. It produces ‘consciousness’.
    c. It houses a ‘well’ of morality (free will: goodness/evil).

    However, in this comment I will show the ‘base’ and the connection only for [a]. Yes, I must first give some precise definitions.

    One, intelligence: the precise definition is available at . At here, it will be defined as the consequence of ‘information processing’. Then, what ‘machine’ does this job? Is there more than one type of machine able to do this job? What is the ‘essence’ of this process?

    The ‘essence’ of this process is ‘computing’. Thus, the ‘machine’ should be a computing device (counting straws, abacus, or a Turing computer). Thus, this ‘intelligence’ issue can be outlined with three parts.

    Part one, in the ‘base’, the physics laws: a Turing-like device must be ‘imbedded’ in the elementary particles (such as, proton or neutron).

    Part two, in the ‘bridge’, the manifestation ‘process’: it can be outlined with the following three facts.
    I. All computable ‘functions’ are recursive functions. [Note: I will not discuss the uncomputable functions at this time.]
    II. All recursive functions are Turing computable.
    III. All ‘languages’ are recursively defined. That is, a Turing-like mechanism is intrinsically embedded in all languages. The simplest language is the bio-language (the DNA language and the protein language). Then, there are the human ‘nature’ languages, the highest tier manifestations.

    Part three, the manifestation: the ‘intelligence’; the product of many tiers of languages (from bio to nature). Note: the nature language is powered by a ‘neural’ machine (see ).

    With these three part framework, it has showed very, very clear of how to link the physics-base (including the quantum principle) to the highest level of manifestation, the intelligence (one attribute of the mind). On the other hand, this framework sets an absolute constrain on the type of the ‘final’ physics law must be; encompassing a Turing mechanism in its rock bottom framework. That is, any ‘empirical’ data which is not supporting this Turing framework cannot be the final data, as it will definitely be another example of fallibility of any empirical data. This mind/physics issue in fact sets the final check in the physics-epistemology.

    Two, the 3-part framework for ‘consciousness’ can also be easily constructed. It is briefly discussed at . Just a short note here, intelligence is not the same as consciousness.

    Quentin Ruyant: “The ‘hard problem’ concerns the phenomenal aspect of consciousness, the subjective first-person “what it’s like” to be conscious. And this question, Chalmers argues, is not scientifically tractable: it is a metaphysical problem.”

    This hard problem is stated with non-scientific, non-philosophical and non-metaphysical language. What does ‘like’ mean? What is ‘conscious’ defined in this hard problem. Without the clearly defined terms, this is a nonsense statement.

    Note: please do not confuse this 3-part framework with the traditional panpsychism.


  13. Hi Quentin,

    To be precise, a quantum system can be simulated with a classical system with exponential slowdown

    “Computable” has a technical definition and this is not it. I am aware that it is unfeasible to build classical simulations of quantum systems. The argument about a simulated person is a thought experiment about the principles at stake. I do not propose it as a feasible project.


  14. Once you sympathize with the many-worlds interpretation, you have left the subject of explaining the natural world. You are just speculating about some imaginary universe.


  15. Hi Massimo,

    Claim 1: It ought to be possible to build an electronic system which can behave just like a human, processing visual input, making decisions appropriately, navigating a physical environment (e.g. with a robot body), passing the Turing test etc.

    Claim 2: It ought to be possible to build an electronic system which is actually conscious.

    Unless you think the two claims are equivalent (as I do), then I think you implicitly acknowledge the legitimacy of the hard problem. Claim 1 is just the claim that a computer program can solve the easy problems. Claim 2 is that a computer program can solve the hard problem. The irony,it seems to me, is that Chalmers should be your natural ally. The fact that you don’t agree that there is a hard problem seems to me to make your position inconsistent.


  16. Ok, granted. But this is more than a mere technical limitation that could be overcome…

    This is so if you are right that quantum mechanics is crucial. It may be that a much cruder simulation would behave substantially the same, as is the case for the simulation of other macroscopic systems.

    Massimo’s objections however are not founded in your QM ideas. He is quite happy to consider the possibility that a person might be simulated accurately enough to behave like a person, and quite certain that such a simulation would not be conscious.


  17. There might be interesting points in what you say, but they seem too vague and general for me to evaluate (and not particularly connected to contemporary philosophy of science, which mainly builds on logical empiricism and its critics).


  18. So you seem to agree with me after all?
    Now any explanation has to stop somewhere, and it seems to me that in the case of a bridge, classical explanations are good enough (just take the cable resistance as an input parameter).


  19. DM, as I said, I seriously doubt that going through this debate again will improve things. The (to me, obvious) difference btw (1) and (2) is that (1) is described behavioristically, while (2) is described phenomenologically. You simply cannot infer phenomenology from behavior without further assumptions, which is why I wrote that the Turing test is useless for detecting consciousness. Given that, your conclusion does not follow and Chalmers is certainly not my ally.


  20. I don’t really see the point – both Mary and the Black and White Room and the Zombie argument were never much cop in the first place.

    They both just rely on a premise that assumes the conclusion. For example “Mary has all the physical facts about colour vision but has never seen a colour”. Built into that premise is the assumption that the experience of colour is not a physical fact.

    Similarly the p-zombie is “physically identical to us but is not conscious”. Again, that has simply built in the assumption that consciousness is not physical.

    Injecting QM is unnecessary and confuses the matter. Furthermore I can’t see how it works – the p-zombie world is a different possible world rather than the p-zombie being a physical duplicate.


  21. Here are some medical facts. Behavior, in any mammal and primate is “decided” in 140ms. There is literally no time for anything that could be related to any concept of the mind to have any effect on behavior. subjective experiences, emotions, thinking, decision making, values, counter-factual thinking, etc. — all of these occur in, mainly, academic English language ( as currently presumed) and there is no time for any of that to have any biological, physiological effect on behavior. Cites include Glimcher and Cisek.

    The mind is blind to the processes of the brain, like any organ of the body. The mind, everyday academic English language, has no more insight into the workings of the brain > behavior than the spleen, by definition.


  22. Hi Massimo,

    You draw a distinction between behaviour and phenomenology. This is precisely the same distinction Chalmers draws between the easy and hard problems, so, again, I don’t understand why you have a problem with Chalmers’ framing of the distinction when it seems to be no different from yours in substance.


  23. If you don’t buy the argument it adds nothing indeed (although identifying an experience with a fact is a bit contentious). About how it works in the case of zombies, that’s a good point, I have already answered above: it depends on how you interpret metaphysical possibilities, and I admit it doesn’t go without saying.


  24. “I” don’t mean anything. The experimental work shows that behavior is the result of competition between stimuli that occurs in 140 ms.

    Humans no more decide, plan and think about behavior any more than any other animals that we are descended from, of course.

    Medically the hard problem of consciousness is a false problem. See also the no free will research, of course. If all the time of philosophers isn’t taken up discussing zombies, that is.


  25. Yes, both Chalmers and I draw a (I would say obvious) distinction btw phenomenology and behavior, but that’s where the similarity ends. He then goes on deriving the bizarre conclusion that there is something seriously wrong with our metaphysical view of the world; I limit myself to saying that once (if) we will have solved all the “easy” problems we will have a scientific account of phenomenal consciousness, and we might even be able to replicate it (as opposed to simply simulate it). BIG difference.


  26. “We’re a complex mix of biases and heuristics and statistical reasoning. When you put it all together, that’s how you get sophisticated behavior. We don’t know where a lot of these biases come from, but this study—and others like it—suggest many of them are due to cognitive mechanisms we share with our primate relatives,”


  27. I have a suggestion.

    Go outside and sucker-punch a passer-by. Then, when you’re in court, standing before the judge, charged with aggravated assault, explain to him what you’ve written above: that intentions, decision making, values, counter-factual thinking, etc., had nothing to do with what you did, since “behavior in any mammal and primate is decided in 140ms”, and that aggravated assault occurs only in “mainly academic English.”

    Let us know how it goes.


  28. Hi Massimo,

    Interesting. Your position may be coming clearer to me.

    But would you say the possibility remains open that we might solve the easy problems without solving the hard problem? If it seems nomologically possible that we could have an intelligently behaving computer system which is not conscious, wouldn’t that imply that this is the case?


  29. > “The experimental work shows that behavior is the result of competition between stimuli that occurs in 140 ms.”

    But if “I” follow you, noone really did that experimental work (which would require planning), so noone really knows that what “you” are saying is true (not even “you” actually).

    > “Medically the hard problem of consciousness is a false problem.”

    A bit like saying that urbanistically, the problem of dark matter is a false problem.


  30. At least my dog has decided not to swim even in summertime. I have decided not to swim in winter but sometimes I do change my behavior and swim. Seems to me that animal behavior is different to the human one.


  31. Quentin Ruyant: “… but they seem too vague and general for me to evaluate …”.

    I will make my view crystal clear with two points.

    One, ‘mind’ is an empirical reality, zillion times more empirical than any physics-data (such as, the LHC data). And, the intelligence (an attribute of the mind) is definitely powered by a Turing-like device. Then, this Turing device ‘must’ be embedded in the physics-laws (the base for the mind-manifestation). That is, the Turing framework is a ‘linking-thread’ between the base (physics laws) and the manifestation (the mind).

    Two, this linking-thread is the absolute physics-theory confirmation criterion which preempts all empirical data. If a physics empirical data does not meet this linking-thread criterion, it is only a fallible data, definitely not data for a permanent truth. Empirical data in the Popperianism is always fallible while the linking-thread criterion is the Gospel.

    I am not just talking about these two points with talking. Today, we have one excellent example for checking this linking-thread criterion. The Higgs mechanism has no chance of any kind meeting this linking-thread criterion, that is, it cannot be ‘correct’. With this criterion alone, I will bet my bottom dollar that Higgs mechanism is simply wrong. Fortunately, I do have two other facts supporting my bet.

    Fact one, two years after the discovery of 126 Gev boson, the Higgs mechanism is neither understood nor proven. See, .

    Fact two, there is a framework which does meet the ‘mind/physics linking-thread criterion’. Although the M-string theory failed to produce the ‘string-unification’, it is done in a different framework (see, ). Then, with this ‘string-unification’, both proton and neutron are in fact embedding a Turing device (see, ), meeting this ‘mind/physics linking-thread criterion’.

    I think that this ‘mind/physics linking-thread criterion’ is no longer vague and general. It gives a precise ‘prediction’ that Higgs mechanism is wrong.


  32. Ah, glad we are making some progress! I have no doubt that one can build an intelligently behaving computer that is not conscious. But that computer will not be able to feel anything, i.e., to have qualia, unless it was also somehow endowed with consciousness. Which brings me back to why there is no hard problem: the problem is to figure out how neurons and other biological components (or whatever) produce the ability to have phenomenal experience. Once that is solved there is no further problem left hanging.


  33. Hi Massimo,

    But that computer will not be able to feel anything, i.e., to have qualia, unless it was also somehow endowed with consciousness.

    Agreed (for the sake of argument).

    Would it not be the case that building such a computer would involve solving all the easy problems? Because the easy problems, if I understand Chalmers correctly, are all the objective information-processing problems.

    the problem is to figure out how neurons and other biological components (or whatever) produce the ability to have phenomenal experience. Once that is solved there is no further problem left hanging.

    Right. But the building of an intelligent computer would not necessarily mean we have the answer to that question, because the computer is not actually conscious. So there could be a problem left hanging, as you say. And this is Chalmers’ hard problem.


  34. hmm, maybe we are not making as much progress as we thought, after all. Okay, one more tack, then I’m going to take a break from this, ahem, recurring discussion.

    I make a distinction between intelligence and consciousness. I don’t doubt that there are many ways to build intelligent computers, but I’m somewhat more skeptical that there are that many ways of producing consciousness. Regardless, if we consider the case of beings that look like us, behave like us, and – crucially – are internally constituted like us, then they must be conscious, as a matter of physical necessity.

    That this is not a logical necessity doesn’t bother me in the least. It is not logically necessary for H2O to have the physical properties that it does, but physically it couldn’t be otherwise (given the laws of this universe). Would this water-related decoupling between logical and physical necessity bother you? Would it make you into a dualist? Would it force you to suspect that there is something awry with our metaphysical view of the world?


  35. Hi Massimo,

    I make a distinction between intelligence and consciousness.

    Understood. Me too. Chalmers too.

    I don’t doubt that there are many ways to build intelligent computers, but I’m somewhat more skeptical that there are that many ways of producing consciousness.


    Regardless, if we consider the case of beings that look like us, behave like us, and – crucially – are internally constituted like us, then they must be conscious, as a matter of physical necessity.

    Understood. But I’m not trying to make a point about p-zombies now. I’m trying to establish that the hard problem is not one you ought to dismiss.

    Easy problems = intelligence.
    Hard problem = consciousness.

    On your view, we might solve the easy problems without solving the hard problem.

    Ergo, the hard problem is distinct from the easy problems on your view.

    Ergo, the hard problem is not to be dismissed on your view.

    I’m not sure that the water/H2O points are particularly related to what I’m trying to say, but I’ll answer your questions if you disagree.


  36. Hi DM,

    I would note that making sense of frequentist probability in infinite sets is a general problem in mathematics. We have the intuition that an arbitrarily chosen integer has a 50% chance of being even, and I suspect that intuition is correct. However, different ways of ordering or choosing the integers can yield different probabilities. I don’t think this really means the intuition is wrong, or at least that there is not at least some respect in which it is correct. In any case, whether the MWI is correct or not, the mathematical problem remains.

    I would question whether you can even meaningfully talk about arbitrarily choosing a member of an infinite set.

    If you arbitrarily chose a million numbers from the set of natural numbers, what would the average be? The question of course does not have an answer.

    So I think you have to be a bit careful about probabilities in infinite sets. Maybe it is not a question of whether or not the intuition is correct but rather whether the question is meaningful at all.


  37. Hi Coel,

    Which arguments convince you that there is something about consciousness that is beyond materialistic science?

    The problem for me has always been that there has never been anything approaching a rigorous statement of the Hard Problem of Consciousness or even a decent informal statement of it.

    It seems to me that we should not worry about a problem if it cannot be stated.

    On the other hand I have never seen a decent statement of what “materialistic” means in the context of “materialistic science”.


  38. Hi Quentin,

    For example, the zombie argument convinced me that if we think of physics in a classical way (determinate properties assigned to objects in space-time), phenomenal aspects are in principle beyond physics.

    It is a long time since I looked at the paper, but as I remember, it relied a lot on accepting Chalmers’ Two Dimensional semantics and I am far from accepting that. For a start it is something that Chalmers has never really completed.

    And, as I said earlier, it relies very much upon the premise that phenomenal aspects are not physical and so it is not really surprising that he can derive that conclusion.

    As I recall he derives a conclusion that Materialism is false without really ever defining what he means by the term.

    And he refers often to these “microphysical facts” without really defining how a fact can be classified as being “microphysical” or not.

    I have my own doubts about consciousness being in the domain of physics but I would come at this in a different way.


  39. Hi Massimo,

    And my contention is that it has nothing whatsoever to do with p-zombies who, btw, are supposed to be physical, not virtual.

    For what I mean by a simulation and what, I believe, DM also means – think of the OpenWorm project. If that succeeds then it will be a simulation of C Elegans.

    Think of that project extended to a human and that is what I mean by a simulation of a human being.

    It is not the same as the p-zombie argument but a similar point is being made.

    We can argue about whether or not something like a p-zombie is a metaphysical possibility, whatever “metaphysical possibility” might mean.

    But it seems that the possibility of the human simulation that models all the externally observable behaviours of a human seems to be a consequence of Naturalism.

    The problem does not rely on any assumption about whether or not such a simulation would be conscious because it poses problems whether or not you consider the simulation would be having conscious experiences.

    To me this is a much better statement of the problem of consciousness.


    For anyone who is interested, here is an essay I wrote for the “Moral Landscape Challenge” but did not submit. This puts the same point in a different way.


  40. Hi Massimo,

    Regardless, if we consider the case of beings that look like us, behave like us, and – crucially – are internally constituted like us, then they must be conscious, as a matter of physical necessity.

    That this is not a logical necessity doesn’t bother me in the least. It is not logically necessary for H2O to have the physical properties that it does, but physically it couldn’t be otherwise (given the laws of this universe).

    Firstly, strictly speaking is is logically necessary for H2O to have the physical properties it does because anything that did not have those properties would not be H2O but something else.

    Something that did not have the physical properties of H2O would not behave as H2O does and would have a different mathematical description.

    A p-zombie, on the other hand, would have exactly the same mathematical description and would behave exactly as does a person – so the analogy is not apt.

    I think that if you say that it is logically possible for something to have our precise physical make up and behave exactly as we do (including talking about consciousness and subjective experiences such as pain) then you are saying there is a problem.

    The fact that this logical possibility is not instantiated is not to the point, but if it is logically possible then you are saying that physics does not require the hypothesis of consciousness to describe the universe, including us.


  41. Hi Orwell,

    I am not sure why that is a problem. Presumably they are serving the same role in Idealism as they do in any scientific description.

    If there was a scientific account of how these mechanisms produce subjective experiences, such as nausea or pain, then that might be a problem for Idealism.

    But currently there is not even any good working hypothesis or even a conceptual link between neural mechanisms operating and the feeling (for example) of nausea.


  42. DM,
    “Easy problems = intelligence.
    Hard problem = consciousness.”
    So why not go with that and see what results when you look at this distinction between observer/consciousness and observed/intelligence.
    That would make consciousness axiomatic, which amounts to a bottom up spirituality. That would undermine the premise of monotheism, that the spiritual absolute is an ideal from which we fell. This would undermine the divine right of kings and other power figures, while explaining why the natural order is bottom up and emergent, not top down and to be dictated by authority.
    Start a movement on that premise and you will find a lot of people willing to go along.


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