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Cambridge University Press eBooks

Panpsychism and neutral monism

Alexander E. Wendt

Published Apr 20, 2015• 0 citations
Publisher

Abstract

Although this book is about the implications for social science of a quantum approach to the mind, much of that potential stems from its ability to integrate consciousness – a particular aspect of the mind – into a naturalistic worldview. And when it comes to the hard problem, quantum brain theory is only a necessary condition for such integration, not sufficient. Necessary, because it would enable the body to exploit for macro-level purposes a physical but non- material space for consciousness at the quantum level – collapse of the wave function – that does not exist in classical physics. Insufficient, however, because quantum brain theory embodies an objective, third-person standpoint and as such can tell us no more than classical brain theory can about why brains have a subjective, first-person point of view in the first place. The explanatory gap is still there, in other words, only now pushed down into quantum theory. To cross this gap, therefore, in addition to a new physics of the brain we will need a new meta -physics as well. As I argue in this chapter, it is this metaphysics that does the real work in solving the mind–body problem. Most social scientists have an instinctive aversion to ‘metaphysics,’ which in our world connotes wooly-headed and speculative thinking that has no place in science. Yet in moving onto this terrain the situation is both worse and better than that. It is worse because we have no choice. The Neuron Doctrine itself is based on a metaphysic, materialism, which looks increasingly unlikely to ever explain consciousness; and in thinking about the meaning of quantum theory metaphysical debate can hardly be avoided, precisely because physics provides little guidance for choosing among its interpretations. So the only question is whether to change our metaphysics of the brain from classical to quantum.

DOI
10.1017/cbo9781316005163.008

Related papers

Quantum consciousness and life

Alexander E. Wendt

Introduction We saw in Part I that in addition to explaining consciousness there is another hard problem for the modern scientific worldview – understanding what quantum physics is telling us about reality. And if anything this one is harder. In philosophy of mind there is at least consensus enough for an orthodox position to exist (materialism), and a widespread expectation that it will be vindicated by future neuroscience. By contrast, in philosophy of physics all sides understand that quantum theory is compatible with a variety of metaphysical interpretations, and have little hope that new empirical discoveries will settle the matter. But both problems are “hard” in the sense that, despite tremendous intellectual effort over many decades, no clear progress has been made toward solving them. The basic idea of quantum consciousness theory is that bringing the two problems into contact may be the key to solving both (though I will be addressing only the mind–body problem in what follows). That this could be a novel idea attests to the fact that their philosophical discussions have evolved quite separately. While philosophers of physics have long been interested in the role of consciousness in the measurement process, they have engaged little with the mind–body problem per se; and philosophers of mind have been almost unanimous in dismissing the suggestion that consciousness has anything interesting to do with quantum physics. Social scientists might echo such skepticism, wondering how adding the problem of interpreting quantum theory to the problem of consciousness will help them . Besides piling up jargon and arcane debates, in moving to the sub-atomic level we are now even farther removed from the human world, and seemingly poised to engage in the most vulgar reductionism. Yet, naïvely one might expect the two problems to be related, for two reasons. The first is the intriguing analogies mentioned in Chapter 1 between the mental and quantum domains.

Cambridge University Press eBooks•Apr 20, 2015•0 citations

Five interpretations

Alexander E. Wendt

While there is general agreement that quantum theory poses a fundamental challenge to the classical worldview, there is none on what worldview should replace it. This lack of clear positive implications is the heart of the interpretation problem in quantum theory, or understanding what the world must be like assuming the theory is true. The difficulty is twofold. First, if the theory is correct and complete then there seems to be no way to adjudicate empirically among its interpretations, forcing us to rely on metaphysics instead. Second, the classical metaphysics upon which human beings have relied in the past to interpret new theories is now itself problematic, leaving us without an interpretive backstop to anchor our thinking. Bell is surely right in expecting whatever picture of reality eventually emerges from quantum theory to “astonish us,” but by the same token it is very hard to see what that picture should be. In this chapter I address the debate about the positive worldview implications of quantum theory. Of all the chapters in this book it is the farthest removed from the concerns of social scientists. However, it plays an important dialectical function in my argument, which is to introduce and help justify the panpsychist interpretation of quantum theory that I will embrace and discuss at more length in Chapter 6. By ‘justify’ I do not mean that I will defend this interpretation as superior to others. My purpose is more modest, which is simply to show why, despite what might seem to be its bizarre and counter-intuitive nature, panpsychism is taken quite seriously by philosophers of physics as a way to interpret quantum theory. That's because (a) there are strong analogies between quantum systems and the human mind, and (b) the alternatives are equally bizarre and counter-intuitive. If readers are prepared to accept that panpsychism is a valid approach to the mind–body problem, then this chapter may be skipped – which I have made less costly by deferring until Chapter 6 a discussion of time-symmetric approaches like the Transactional Interpretation, which will play an important role later in the book.

Cambridge University Press eBooks•Apr 20, 2015•0 citations

Consciousness and Quantum Mechanics

Jonathan Simon

This book is a treat, a collection of essays about the relationship between consciousness and quantum mechanics that is guaranteed to move the needle: serious, original, and relatively accessible. The essays develop cutting-edge views by thought-leading authors on questions that matter for the philosophy of physics and the philosophy of mind, and while to follow along you need to know what supervenience is and what an eigenstate is, the majority of essays should be accessible to advanced undergraduates (i.e., those who have taken a rigorous introductory course in quantum mechanics as well as a course or two in the philosophy of mind).Why care about the relationship between consciousness and quantum mechanics? If you are coming from physics, your point of entry is probably the measurement problem. When you let quantum systems evolve according to the Schrödinger equation, they enter into superpositions of mutually incompatible states. How can this be reconciled with the testimony of our senses that such systems are always in one state or the other when we measure them (with a probability distribution given by the Born rule)? This is the measurement problem, and it concerns consciousness because it draws from the testimony of our senses.If you are coming from the philosophy of mind, your primary concern is probably the mind-body problem: the task of accounting for how consciousness arises out of or fits into physical reality. If consciousness is reducible, how might the details of quantum mechanics make it harder, or easier, to establish that reduction? If consciousness is irreducible, how might the details of quantum mechanics make it harder, or easier, to explain why consciousness exists, or to find some work for it to do in the world? You may also be concerned with the structure and function of consciousness: for example, you may hold that minds can do things that classical digital computers cannot, and take it that we must look to the quantum realm to discover how.If you are not already entrenched, you might just wonder what kind of world we live in. The mechanistic philosophy of centuries past seemed to disenchant the world, rendering it a place of barren corpuscles banging into one another, leaving no room for mind or meaning, except perhaps as patterns in the collisions, or useless epiphenomena. But quantum mechanics and its relativistic generalizations force a rethinking of the mechanistic picture from the ground up. Once the dust has settled—if it ever does—we may find reasons to relegate consciousness once again to the shadows. But we may also find reasons to give it pride of place. If you are after scientific reasons to reenchant the world, this is a good place to look.The entries in this volume address these questions and others besides. The volume is organized into three parts. The first part contains four essays about the idea that consciousness causes (or constrains) quantum collapse. The second part contains eight essays discussing other ways that consciousness might contribute to theories of quantum mechanics. The third part contains five essays about how quantum mechanics might contribute to an ultimate theory of consciousness. I’ll follow the book’s order.In chapter 1, David Chalmers and Kelvin McQueen develop a new consciousness-triggered collapse interpretation of quantum mechanics. On their approach, consciousness has a strict physical correlate (perhaps given by quantum integrated information theory), it is approximately superposition-resistant, and collapse dynamics are continuous (à la Philip Pearle). They respond to the standard objections that a consciousness-collapse link makes the collapse mechanism imprecise and requires dualism, as well as to worries about Quantum Zeno, among others. Crucially, their approach allows that superpositions of consciousness are possible: their motivation is to give the view a run for its money and to find work for consciousness to do in the universe, not to rid the world of all traces of superposed consciousness. One question: In taking consciousness itself to be superposition-resistant (rather than the environmental systems it asks questions about, as Henry Stapp suggests), we appear to favor internalism over externalism. What would an externalist variant look like? Another question: How exactly would experimental results—for example, that simple enough systems with maximal Φ remain in coherent superposition—constrain our theoretical options? If to accommodate this we have to impose an experimentally determined threshold for the minimal absolute Φ for consciousness, will that mean that on the physicalist version of the view, the property we privilege for superposition-resistance is just an arbitrary collection of atoms?In chapter 2, Elias Okon and Miguel Angel Sebastian defend a consciousness-collapse theory that they call the Subjective-Objective collapse model. Like Chalmers and McQueen, Okon and Sebastian invoke a Pearle-style continuous collapse dynamics and think of consciousness as only weakly superposition-resistant. A key contribution is the treatment of a worry about multiple realizability (i.e., the way that some property of biological neurons and some other property of artificial neurons might both realize the state of being in pain). The problem is that it is not straightforward to define Hermitian operators whose eigenstates are disjunctions of the eigenstates of other Hermitian operators: you must ensure orthogonality (“being red or being a circle” is not orthogonal to “being red or being square”). In answer, the authors point out that we don’t need each multiply realizable phenomenal state to be an eigenstate of our collapse operator; it suffices that each way of realizing each phenomenal state is an eigenstate. One question is whether this problematizes the dancing qualia argument. A second worry is that we still must find a suitable basis for Hilbert space. But theories of consciousness may constrain both position and momentum: for example, both distances between neurons and how energy is transferred. We can talk about wave packets, but these will not get us eigenstates of a Hermitian operator.In chapter 3, J. Acacio de Barros and Carlos Montemayor suggest that if a mentality-triggered collapse theory is what you want, you should opt for intentionality rather than phenomenality. This is because, first, we have evidence from psychophysics that there is unconscious perception. Second, the first-personal data that motivate collapse theory concern intentionality: we remember only recording definite values; our decisions about what to measure affect the outcomes we see. First question: Can the reasons we have for thinking that there is unconscious intentionality extend into a case for unconscious primitive intentionality? Another question is how the proposal here would differ from Stapp’s treatment of what questions a mind asks of the universe. A third is how we contend with Quantum Zeno, the effect that forces both Chalmers-McQueen and Okon-Angel Sebastian to say that consciousness is only weakly superposition-resistant. Those authors note the possibility that the relevant superposed states of consciousness might overflow access consciousness (in Ned Block’s sense). We may have an easier time ensuring that access conscious states only rarely enter into superposition, if we set them back from our front line of superposition-resistant states.In chapter 4, Adrian Kent explores objective collapse theories—mass-dependent continuous spontaneous localization models. Consciousness may not be in the spotlight on these theories, but they should at least ensure that collapse happens faster than the time it takes for a stimulus (e.g., a system of several photons) to make it from a retinal impact to consciousness. Angelo Bassi, Dirk-André Deckert, and Luca Ferialdi (2010) argue that for a range of theories this constraint is respected, with collapse for a system of several photos happening at around 100 ms. Kent problematizes their argument, showing that their estimation may be off by an order of magnitude or more. Kent’s point is compelling: more work is needed to refine the estimate and to conceptually clarify the import of the constraints from perception.Part 2 consists of eight essays on various ways that consciousness might figure in or constrain quantum theories. In chapter 5, Phillip Goff argues that 3N-dimensional wave function monism cannot accommodate ground truths about consciousness, pressing on worries that the view imposes too few structural constraints to allow for the unambiguous recovery of ordinary 3D reality. While I agree that wave function monistic accounts of ordinary reality (e.g., Albert’s functionalism or Ney’s priority monism) yield an explanatory gap (even given the 3D-ish structure of GRW jumps), I was puzzled here. All type-B physicalists confront an explanatory gap where consciousness is concerned. Isn’t this a point in support of wave function monism, since it amounts to a companions-in-guilt argument against opposition from other type-B materialists?In chapter 6, Peter Lewis raises some sensible worries about the use of phenomenal consciousness as an unanalyzed primitive or special case in quantum theory. He objects to the suggestion made by some Bohmians that we can be directly aware of the particles in our brains. Another target is John von Neumann, who appeals to intuitions about psychophysical connections to justify a collapse hypothesis. These are nice points: I would be curious to know whether Lewis thinks they apply to the justifications for mentalistic collapse theories from part 1.In chapter 7, Jenann Ismael first argues that the hard problem of consciousness is of no concern to physics per se: “If consciousness enters the problem space of physics, it does so by making a difference to the behavior of physical objects.” She then offers some clarifying remarks about how we might reconcile Van Gelder-style dynamicist conceptions of mentality with (virtual) machine functionalism. I find much to agree with here, though I do wonder how strictly to take Ismael’s claims about the irrelevance of the hard problem. If there is a tie between two theories of physics over predictive accuracy, elegance, and naturalness, but one yields a more satisfying analysis of consciousness than the other, are we not even allowed to treat that as a tie-breaker?In chapter 8, Shan Gao defends a mentalistic characterization of the measurement problem in reply to Andrea Oldofredi (2019). The question is whether the key premise of the measurement problem should be that measurements take on definite values or only that we (definitely) experience them as taking on definite values. Of course, our reasons for thinking that they do arise from our seeing or remembering that they do, but we can distinguish between the claim and our evidence for it. Gao argues that the underlying mentalistic claims are more inextricable from the dilemma than that. Many dilemmas involve premises for which the evidence is perceptual, though they make no mention of perception. Here, however, solutions to the problem require special attention to the nature of that evidence.In chapter 9, Paul Skokowski illustrates one reason that we must pay special attention to the nature of that evidence. Jeffrey A. Barrett’s (1999) bare theory is a minimalistic reading of Everett on which measurement outcomes are only definite if they obtain on all branches. One question is whether this means that observers have blatantly false disjunctive beliefs: let someone measure an electron’s spin and then ask, Do you believe that you got a definite measurement outcome, either “UP” or “DOWN”? The observer will say yes, because on each branch they saw one and not the other. However, by the lights of the theory, this disjunctive belief is false. Skokowski’s insight is that while the observer definitely says yes, it does not follow (by the lights of the bare theory) that the observer has a (definite) false belief, since the neural realizer for the disjunctive belief will be different on each branch and therefore not correspond to a common eigenstate (compare the worry from chapter 2 about multiple realizability). But isn’t this just to move from the frying pan to the fire, as it seems now that our observer has no (definite) beliefs at all?In chapter 10, Michael Silberstein and W. M. Stuckey advocate for a psi-epistemicist perspective that vindicates many phenomenological intuitions, including the one that experimental outcomes are definite (and intersubjectively consistent). The approach requires that we rethink naïve realism about the wave function and that we rethink mind-body duality, in favor of a neutral monist ontology governed by constraints. This is an exciting approach, though I’m not fully clear on how to differentiate neutral monism from its idealist, dual aspect, or panpsychist cousins.In chapter 11, Michael Bitbol suggests a phenomenology-first approach to interpreting quantum mechanics. Bitbol favors a QBist participatory realism, tempered by phenomenology, that could perhaps also be described as neutral monist. He notes that the phenomenology of embodiment (à la Merleau-Ponty) acquaints us with how something can be both active and passive, both minded and incarnate, and he traces the error of believing in a separate, physical world (an error participatory realism corrects) to the tendency of self-separation: the tendency to try to project ourselves beyond ourselves, discussed in Heidegger, Sartre, and Michel Henry. These phenomenological insights are enlightening, though I am still not quite clear on how the underlying (neutral?) ontology works. Who, precisely, are the observers? Do electrons have feelings, or are they just fictions we use to cope with ours?In chapter 12, Lucien Hardy describes an experiment in which humans might be used to determine the settings in a Bell experiment. Hardy suggests that the outcome may be a violation of quantum theory consistent with the Bell inequality. He argues that this result would support (superdeterministic) mind-body dualism and also could serve as a new more objective Turing test. This is a fascinating proposal: it remains only to do the experiment.This brings us to part 3: accounts that move from quantum mechanics to consciousness, rather than conversely. In chapters 13 and 14, Roger Penrose and Stuart Hameroff give a comprehensive account of the current state of their ORCH-OR theory of quantum collapse and consciousness. Among other things we find here a nice presentation of Goodstein’s theorem as an example of a theorem that is noncomputable but easy enough for humans to understand, and a nice discussion of how retroactivity might equip us with something to say to Benjamin Libet about the role of consciousness in action selection. I’ll note, though, that I asked ChatGPT to explain Goodstein to me and it did a fairly good job, suggesting something like understanding. On Libet, I’m not sure what exactly we need retrocausality for: Why not just content ourselves that awareness of the action plan leaves time for a veto, as Libet and others have suggested?In chapter 15, Basil J. Hiley and Paavo Pylkkänen explore another route to a comprehensive theory of consciousness, drawing from the materials of a theory of quantum reality. Here, that theory is the Bohmian implicate order picture, with special attention to the notion of active information that arises there. This is another approach with neutral monist overtones, but here the wave function of a system behaves something like a customized hylomorphic form for the system while at the same time imbuing it with intentionality. There are interesting claims here about the continuity between life and mind, the unity of consciousness, and protopanpsychism, as well as some speculation of how the theory might align with the various scientific theories of consciousness inspired by psychophysics, like higher-order or global workspace theories.In chapter 16, William Seager offers a helpful discussion of the kinds of intelligibility at issue in these debates, distinguishing between mundane, mathematical, and metaphysical intelligibility, weaving together insights from Leibniz and others to argue that a Bohmian approach offers the best bet for a metaphysically intelligible world view. I sympathize with the positive aspects of his argument, though I think that other papers in this volume showcase the metaphysical intelligibility of rival approaches.Finally, in chapter 17, Lee Smolin describes a completion of quantum mechanics, also echoing Leibniz, which could support a theory of quantum gravity and which offers a new conception of consciousness: the causal theory of views, alongside the principle of precedence. This yields a novel sort of protopanpsychism in which the world is a collection of (background-independent) causal views, where views are conscious when they have a few extra features, including being unprecedented and being maximal. This is an exciting approach. One question is how we reconcile the claim that experiential states are maximal with the (mental) problem of the many, the problem that there are ties between composites (that differ over a stray ion or two) over which has best claim to be me.In closing, this is a fantastic volume. I commend Shan Gao for his editorial work: he would make a wonderful DJ. There are subtle symmetries in the way that each entry segues to the next, and the collection has a remarkable coherence.

The Philosophical Review•Jul 1, 2024•0 citations

Re-Thinking the World with Neutral Monism:Removing the Boundaries Between Mind, Matter, and Spacetime

Michael Silberstein, W. M. Stuckey

Herein we are not interested in merely using dynamical systems theory, graph theory, information theory, etc., to model the relationship between brain dynamics and networks, and various states and degrees of conscious processes. We are interested in the question of how phenomenal conscious experience and fundamental physics are most deeply related. Any attempt to mathematically and formally model conscious experience and its relationship to physics must begin with some metaphysical assumption in mind about the nature of conscious experience, the nature of matter and the nature of the relationship between them. These days the most prominent metaphysical fixed points are strong emergence or some variant of panpsychism. In this paper we will detail another distinct metaphysical starting point known as neutral monism. In particular, we will focus on a variant of the neutral monism of William James and Bertrand Russell. Rather than starting with physics as fundamental, as both strong emergence and panpsychism do in their own way, our goal is to suggest how one might derive fundamental physics from neutral monism. Thus, starting with two axioms grounded in our characterization of neutral monism, we will sketch out a derivation of and explanation for some key features of relativity and quantum mechanics that suggest a unity between those two theories that is generally unappreciated. Our mode of explanation throughout will be of the principle as opposed to constructive variety in something like Einstein's sense of those terms. We will argue throughout that a bias towards property dualism and a bias toward reductive dynamical and constructive explanation lead to the hard problem and the explanatory gap in consciousness studies, and lead to serious unresolved problems in fundamental physics, such as the measurement problem and the mystery of entanglement in quantum mechanics and lack of progress in producing an empirically well-grounded theory of quantum gravity. We hope to show that given our take on neutral monism and all that follows from it, the aforementioned problems can be satisfactorily resolved leaving us with a far more intuitive and commonsense model of the relationship between conscious experience and physics.

Entropy•May 14, 2020•21 citations

Quantum brain theory

Alexander E. Wendt

In recent decades it has become common throughout the social sciences to think of the human mind simply as a very complex computer. Drawing on an older materialist metaphor of the mind as a machine, the “computational” model of the mind took off after the mid-century invention of the computer and subsequent cognitive revolution in psychology, and has since permeated the social sciences in the form of rational choice and other prominent social theories. The contributions of this model have been huge; but it has always been assumed that the computations going on inside our heads are classical. Quantum brain theory challenges this assumption by proposing that the mind is actually a quantum computer. Classical computers are based on binary digits or “bits” with well defined values (0 or 1), which are transformed in serial operations by a program into an output. Quantum computers in contrast are based on “qubits” that can be in superpositions of 0 and 1 at the same time and also interact non-locally, enabling every qubit to be operated on simultaneously. The idea of a quantum computer was first proposed in the 1980s and is still far from being realized technologically, but it has fired the imagination of scientists by raising the prospect of unimaginable increases in computational power, and other neat tricks besides. If quantum brain theory is true, then our model of the mind would be similarly radically altered, irrespective of the issue of consciousness. Quantum brain theory hypothesizes that quantum processes at the elementary level are amplified and kept in superposition at the level of the organism, and then, through downward causation constrain what is going on deep within the brain. On this view, information from the environment is continuously transformed from the macro- to the micro-level, and then channeled back upward into an “internal quantum state,”

Cambridge University Press eBooks•Apr 20, 2015•0 citations

Six challenges

Alexander E. Wendt

Despite scholarly consensus on the empirical facts, ever since its inception in the 1920s there has been deep disagreement about how to interpret quantum theory. “To interpret a physical theory is to say what the world would be like, if the theory were true.” All scientific theories require interpretation, since strictly speaking what they describe are our experiences of the world rather than the world itself. Thus, whether we are trying to explain or merely describe the world, we are always engaged in inference. To make inferences we need a context for interpretation. For any given claim this context is provided locally by related theories, more broadly by disciplinary paradigms, and ultimately by worldview claims about the nature of reality. The challenge in interpreting scientific theories is to integrate them into this hierarchy of knowledge. Usually this is not too difficult. New theories often require adjustments to nearby theories, but in doing so we can rely on paradigms to make them cohere. More rarely paradigmatic assumptions are themselves challenged, but in that case scientists can fall back on their worldview to make sense of the needed changes. By implication, the most difficult interpretive problems arise when our worldview is called into question, which leaves us without any frame of reference on which to fall back. Quantum theory poses a worldview problem. Prior to the quantum revolution the classical worldview could not be tested scientifically and so it was essentially metaphysical. Even though it corresponded to our experience of material objects, we lacked proof that it adequately represented the deep structure of reality. By giving us access to that deep structure for the first time, quantum mechanics made it possible to do such a test, or “experimental metaphysics.” Unfortunately, the results seemed to contradict classical assumptions, at least on the sub-atomic level.

Cambridge University Press eBooks•Apr 20, 2015•0 citations
Although this book is about the implications for social science of a quantum approach to the mind, much of that potential stems from its ability to integrate consciousness – a particular aspect of the mind – into a naturalistic worldview. And when it comes to the hard problem, quantum brain theory is only a necessary condition for such integration, not sufficient. Necessary, because it would enable the body to exploit for macro-level purposes a physical but non- material space for consciousness at the quantum level – collapse of the wave function – that does not exist in classical physics. Insufficient, however, because quantum brain theory embodies an objective, third-person standpoint and as such can tell us no more than classical brain theory can about why brains have a subjective, first-person point of view in the first place. The explanatory gap is still there, in other words, only now pushed down into quantum theory. To cross this gap, therefore, in addition to a new physics of the brain we will need a new meta -physics as well. As I argue in this chapter, it is this metaphysics that does the real work in solving the mind–body problem. Most social scientists have an instinctive aversion to ‘metaphysics,’ which in our world connotes wooly-headed and speculative thinking that has no place in science. Yet in moving onto this terrain the situation is both worse and better than that. It is worse because we have no choice. The Neuron Doctrine itself is based on a metaphysic, materialism, which looks increasingly unlikely to ever explain consciousness; and in thinking about the meaning of quantum theory metaphysical debate can hardly be avoided, precisely because physics provides little guidance for choosing among its interpretations. So the only question is whether to change our metaphysics of the brain from classical to quantum.
Introduction We saw in Part I that in addition to explaining consciousness there is another hard problem for the modern scientific worldview – understanding what quantum physics is telling us about reality. And if anything this one is harder. In philosophy of mind there is at least consensus enough for an orthodox position to exist (materialism), and a widespread expectation that it will be vindicated by future neuroscience. By contrast, in philosophy of physics all sides understand that quantum theory is compatible with a variety of metaphysical interpretations, and have little hope that new empirical discoveries will settle the matter. But both problems are “hard” in the sense that, despite tremendous intellectual effort over many decades, no clear progress has been made toward solving them. The basic idea of quantum consciousness theory is that bringing the two problems into contact may be the key to solving both (though I will be addressing only the mind–body problem in what follows). That this could be a novel idea attests to the fact that their philosophical discussions have evolved quite separately. While philosophers of physics have long been interested in the role of consciousness in the measurement process, they have engaged little with the mind–body problem per se; and philosophers of mind have been almost unanimous in dismissing the suggestion that consciousness has anything interesting to do with quantum physics. Social scientists might echo such skepticism, wondering how adding the problem of interpreting quantum theory to the problem of consciousness will help them . Besides piling up jargon and arcane debates, in moving to the sub-atomic level we are now even farther removed from the human world, and seemingly poised to engage in the most vulgar reductionism. Yet, naïvely one might expect the two problems to be related, for two reasons. The first is the intriguing analogies mentioned in Chapter 1 between the mental and quantum domains.
While there is general agreement that quantum theory poses a fundamental challenge to the classical worldview, there is none on what worldview should replace it. This lack of clear positive implications is the heart of the interpretation problem in quantum theory, or understanding what the world must be like assuming the theory is true. The difficulty is twofold. First, if the theory is correct and complete then there seems to be no way to adjudicate empirically among its interpretations, forcing us to rely on metaphysics instead. Second, the classical metaphysics upon which human beings have relied in the past to interpret new theories is now itself problematic, leaving us without an interpretive backstop to anchor our thinking. Bell is surely right in expecting whatever picture of reality eventually emerges from quantum theory to “astonish us,” but by the same token it is very hard to see what that picture should be. In this chapter I address the debate about the positive worldview implications of quantum theory. Of all the chapters in this book it is the farthest removed from the concerns of social scientists. However, it plays an important dialectical function in my argument, which is to introduce and help justify the panpsychist interpretation of quantum theory that I will embrace and discuss at more length in Chapter 6. By ‘justify’ I do not mean that I will defend this interpretation as superior to others. My purpose is more modest, which is simply to show why, despite what might seem to be its bizarre and counter-intuitive nature, panpsychism is taken quite seriously by philosophers of physics as a way to interpret quantum theory. That's because (a) there are strong analogies between quantum systems and the human mind, and (b) the alternatives are equally bizarre and counter-intuitive. If readers are prepared to accept that panpsychism is a valid approach to the mind–body problem, then this chapter may be skipped – which I have made less costly by deferring until Chapter 6 a discussion of time-symmetric approaches like the Transactional Interpretation, which will play an important role later in the book.
This book is a treat, a collection of essays about the relationship between consciousness and quantum mechanics that is guaranteed to move the needle: serious, original, and relatively accessible. The essays develop cutting-edge views by thought-leading authors on questions that matter for the philosophy of physics and the philosophy of mind, and while to follow along you need to know what supervenience is and what an eigenstate is, the majority of essays should be accessible to advanced undergraduates (i.e., those who have taken a rigorous introductory course in quantum mechanics as well as a course or two in the philosophy of mind).Why care about the relationship between consciousness and quantum mechanics? If you are coming from physics, your point of entry is probably the measurement problem. When you let quantum systems evolve according to the Schrödinger equation, they enter into superpositions of mutually incompatible states. How can this be reconciled with the testimony of our senses that such systems are always in one state or the other when we measure them (with a probability distribution given by the Born rule)? This is the measurement problem, and it concerns consciousness because it draws from the testimony of our senses.If you are coming from the philosophy of mind, your primary concern is probably the mind-body problem: the task of accounting for how consciousness arises out of or fits into physical reality. If consciousness is reducible, how might the details of quantum mechanics make it harder, or easier, to establish that reduction? If consciousness is irreducible, how might the details of quantum mechanics make it harder, or easier, to explain why consciousness exists, or to find some work for it to do in the world? You may also be concerned with the structure and function of consciousness: for example, you may hold that minds can do things that classical digital computers cannot, and take it that we must look to the quantum realm to discover how.If you are not already entrenched, you might just wonder what kind of world we live in. The mechanistic philosophy of centuries past seemed to disenchant the world, rendering it a place of barren corpuscles banging into one another, leaving no room for mind or meaning, except perhaps as patterns in the collisions, or useless epiphenomena. But quantum mechanics and its relativistic generalizations force a rethinking of the mechanistic picture from the ground up. Once the dust has settled—if it ever does—we may find reasons to relegate consciousness once again to the shadows. But we may also find reasons to give it pride of place. If you are after scientific reasons to reenchant the world, this is a good place to look.The entries in this volume address these questions and others besides. The volume is organized into three parts. The first part contains four essays about the idea that consciousness causes (or constrains) quantum collapse. The second part contains eight essays discussing other ways that consciousness might contribute to theories of quantum mechanics. The third part contains five essays about how quantum mechanics might contribute to an ultimate theory of consciousness. I’ll follow the book’s order.In chapter 1, David Chalmers and Kelvin McQueen develop a new consciousness-triggered collapse interpretation of quantum mechanics. On their approach, consciousness has a strict physical correlate (perhaps given by quantum integrated information theory), it is approximately superposition-resistant, and collapse dynamics are continuous (à la Philip Pearle). They respond to the standard objections that a consciousness-collapse link makes the collapse mechanism imprecise and requires dualism, as well as to worries about Quantum Zeno, among others. Crucially, their approach allows that superpositions of consciousness are possible: their motivation is to give the view a run for its money and to find work for consciousness to do in the universe, not to rid the world of all traces of superposed consciousness. One question: In taking consciousness itself to be superposition-resistant (rather than the environmental systems it asks questions about, as Henry Stapp suggests), we appear to favor internalism over externalism. What would an externalist variant look like? Another question: How exactly would experimental results—for example, that simple enough systems with maximal Φ remain in coherent superposition—constrain our theoretical options? If to accommodate this we have to impose an experimentally determined threshold for the minimal absolute Φ for consciousness, will that mean that on the physicalist version of the view, the property we privilege for superposition-resistance is just an arbitrary collection of atoms?In chapter 2, Elias Okon and Miguel Angel Sebastian defend a consciousness-collapse theory that they call the Subjective-Objective collapse model. Like Chalmers and McQueen, Okon and Sebastian invoke a Pearle-style continuous collapse dynamics and think of consciousness as only weakly superposition-resistant. A key contribution is the treatment of a worry about multiple realizability (i.e., the way that some property of biological neurons and some other property of artificial neurons might both realize the state of being in pain). The problem is that it is not straightforward to define Hermitian operators whose eigenstates are disjunctions of the eigenstates of other Hermitian operators: you must ensure orthogonality (“being red or being a circle” is not orthogonal to “being red or being square”). In answer, the authors point out that we don’t need each multiply realizable phenomenal state to be an eigenstate of our collapse operator; it suffices that each way of realizing each phenomenal state is an eigenstate. One question is whether this problematizes the dancing qualia argument. A second worry is that we still must find a suitable basis for Hilbert space. But theories of consciousness may constrain both position and momentum: for example, both distances between neurons and how energy is transferred. We can talk about wave packets, but these will not get us eigenstates of a Hermitian operator.In chapter 3, J. Acacio de Barros and Carlos Montemayor suggest that if a mentality-triggered collapse theory is what you want, you should opt for intentionality rather than phenomenality. This is because, first, we have evidence from psychophysics that there is unconscious perception. Second, the first-personal data that motivate collapse theory concern intentionality: we remember only recording definite values; our decisions about what to measure affect the outcomes we see. First question: Can the reasons we have for thinking that there is unconscious intentionality extend into a case for unconscious primitive intentionality? Another question is how the proposal here would differ from Stapp’s treatment of what questions a mind asks of the universe. A third is how we contend with Quantum Zeno, the effect that forces both Chalmers-McQueen and Okon-Angel Sebastian to say that consciousness is only weakly superposition-resistant. Those authors note the possibility that the relevant superposed states of consciousness might overflow access consciousness (in Ned Block’s sense). We may have an easier time ensuring that access conscious states only rarely enter into superposition, if we set them back from our front line of superposition-resistant states.In chapter 4, Adrian Kent explores objective collapse theories—mass-dependent continuous spontaneous localization models. Consciousness may not be in the spotlight on these theories, but they should at least ensure that collapse happens faster than the time it takes for a stimulus (e.g., a system of several photons) to make it from a retinal impact to consciousness. Angelo Bassi, Dirk-André Deckert, and Luca Ferialdi (2010) argue that for a range of theories this constraint is respected, with collapse for a system of several photos happening at around 100 ms. Kent problematizes their argument, showing that their estimation may be off by an order of magnitude or more. Kent’s point is compelling: more work is needed to refine the estimate and to conceptually clarify the import of the constraints from perception.Part 2 consists of eight essays on various ways that consciousness might figure in or constrain quantum theories. In chapter 5, Phillip Goff argues that 3N-dimensional wave function monism cannot accommodate ground truths about consciousness, pressing on worries that the view imposes too few structural constraints to allow for the unambiguous recovery of ordinary 3D reality. While I agree that wave function monistic accounts of ordinary reality (e.g., Albert’s functionalism or Ney’s priority monism) yield an explanatory gap (even given the 3D-ish structure of GRW jumps), I was puzzled here. All type-B physicalists confront an explanatory gap where consciousness is concerned. Isn’t this a point in support of wave function monism, since it amounts to a companions-in-guilt argument against opposition from other type-B materialists?In chapter 6, Peter Lewis raises some sensible worries about the use of phenomenal consciousness as an unanalyzed primitive or special case in quantum theory. He objects to the suggestion made by some Bohmians that we can be directly aware of the particles in our brains. Another target is John von Neumann, who appeals to intuitions about psychophysical connections to justify a collapse hypothesis. These are nice points: I would be curious to know whether Lewis thinks they apply to the justifications for mentalistic collapse theories from part 1.In chapter 7, Jenann Ismael first argues that the hard problem of consciousness is of no concern to physics per se: “If consciousness enters the problem space of physics, it does so by making a difference to the behavior of physical objects.” She then offers some clarifying remarks about how we might reconcile Van Gelder-style dynamicist conceptions of mentality with (virtual) machine functionalism. I find much to agree with here, though I do wonder how strictly to take Ismael’s claims about the irrelevance of the hard problem. If there is a tie between two theories of physics over predictive accuracy, elegance, and naturalness, but one yields a more satisfying analysis of consciousness than the other, are we not even allowed to treat that as a tie-breaker?In chapter 8, Shan Gao defends a mentalistic characterization of the measurement problem in reply to Andrea Oldofredi (2019). The question is whether the key premise of the measurement problem should be that measurements take on definite values or only that we (definitely) experience them as taking on definite values. Of course, our reasons for thinking that they do arise from our seeing or remembering that they do, but we can distinguish between the claim and our evidence for it. Gao argues that the underlying mentalistic claims are more inextricable from the dilemma than that. Many dilemmas involve premises for which the evidence is perceptual, though they make no mention of perception. Here, however, solutions to the problem require special attention to the nature of that evidence.In chapter 9, Paul Skokowski illustrates one reason that we must pay special attention to the nature of that evidence. Jeffrey A. Barrett’s (1999) bare theory is a minimalistic reading of Everett on which measurement outcomes are only definite if they obtain on all branches. One question is whether this means that observers have blatantly false disjunctive beliefs: let someone measure an electron’s spin and then ask, Do you believe that you got a definite measurement outcome, either “UP” or “DOWN”? The observer will say yes, because on each branch they saw one and not the other. However, by the lights of the theory, this disjunctive belief is false. Skokowski’s insight is that while the observer definitely says yes, it does not follow (by the lights of the bare theory) that the observer has a (definite) false belief, since the neural realizer for the disjunctive belief will be different on each branch and therefore not correspond to a common eigenstate (compare the worry from chapter 2 about multiple realizability). But isn’t this just to move from the frying pan to the fire, as it seems now that our observer has no (definite) beliefs at all?In chapter 10, Michael Silberstein and W. M. Stuckey advocate for a psi-epistemicist perspective that vindicates many phenomenological intuitions, including the one that experimental outcomes are definite (and intersubjectively consistent). The approach requires that we rethink naïve realism about the wave function and that we rethink mind-body duality, in favor of a neutral monist ontology governed by constraints. This is an exciting approach, though I’m not fully clear on how to differentiate neutral monism from its idealist, dual aspect, or panpsychist cousins.In chapter 11, Michael Bitbol suggests a phenomenology-first approach to interpreting quantum mechanics. Bitbol favors a QBist participatory realism, tempered by phenomenology, that could perhaps also be described as neutral monist. He notes that the phenomenology of embodiment (à la Merleau-Ponty) acquaints us with how something can be both active and passive, both minded and incarnate, and he traces the error of believing in a separate, physical world (an error participatory realism corrects) to the tendency of self-separation: the tendency to try to project ourselves beyond ourselves, discussed in Heidegger, Sartre, and Michel Henry. These phenomenological insights are enlightening, though I am still not quite clear on how the underlying (neutral?) ontology works. Who, precisely, are the observers? Do electrons have feelings, or are they just fictions we use to cope with ours?In chapter 12, Lucien Hardy describes an experiment in which humans might be used to determine the settings in a Bell experiment. Hardy suggests that the outcome may be a violation of quantum theory consistent with the Bell inequality. He argues that this result would support (superdeterministic) mind-body dualism and also could serve as a new more objective Turing test. This is a fascinating proposal: it remains only to do the experiment.This brings us to part 3: accounts that move from quantum mechanics to consciousness, rather than conversely. In chapters 13 and 14, Roger Penrose and Stuart Hameroff give a comprehensive account of the current state of their ORCH-OR theory of quantum collapse and consciousness. Among other things we find here a nice presentation of Goodstein’s theorem as an example of a theorem that is noncomputable but easy enough for humans to understand, and a nice discussion of how retroactivity might equip us with something to say to Benjamin Libet about the role of consciousness in action selection. I’ll note, though, that I asked ChatGPT to explain Goodstein to me and it did a fairly good job, suggesting something like understanding. On Libet, I’m not sure what exactly we need retrocausality for: Why not just content ourselves that awareness of the action plan leaves time for a veto, as Libet and others have suggested?In chapter 15, Basil J. Hiley and Paavo Pylkkänen explore another route to a comprehensive theory of consciousness, drawing from the materials of a theory of quantum reality. Here, that theory is the Bohmian implicate order picture, with special attention to the notion of active information that arises there. This is another approach with neutral monist overtones, but here the wave function of a system behaves something like a customized hylomorphic form for the system while at the same time imbuing it with intentionality. There are interesting claims here about the continuity between life and mind, the unity of consciousness, and protopanpsychism, as well as some speculation of how the theory might align with the various scientific theories of consciousness inspired by psychophysics, like higher-order or global workspace theories.In chapter 16, William Seager offers a helpful discussion of the kinds of intelligibility at issue in these debates, distinguishing between mundane, mathematical, and metaphysical intelligibility, weaving together insights from Leibniz and others to argue that a Bohmian approach offers the best bet for a metaphysically intelligible world view. I sympathize with the positive aspects of his argument, though I think that other papers in this volume showcase the metaphysical intelligibility of rival approaches.Finally, in chapter 17, Lee Smolin describes a completion of quantum mechanics, also echoing Leibniz, which could support a theory of quantum gravity and which offers a new conception of consciousness: the causal theory of views, alongside the principle of precedence. This yields a novel sort of protopanpsychism in which the world is a collection of (background-independent) causal views, where views are conscious when they have a few extra features, including being unprecedented and being maximal. This is an exciting approach. One question is how we reconcile the claim that experiential states are maximal with the (mental) problem of the many, the problem that there are ties between composites (that differ over a stray ion or two) over which has best claim to be me.In closing, this is a fantastic volume. I commend Shan Gao for his editorial work: he would make a wonderful DJ. There are subtle symmetries in the way that each entry segues to the next, and the collection has a remarkable coherence.
Herein we are not interested in merely using dynamical systems theory, graph theory, information theory, etc., to model the relationship between brain dynamics and networks, and various states and degrees of conscious processes. We are interested in the question of how phenomenal conscious experience and fundamental physics are most deeply related. Any attempt to mathematically and formally model conscious experience and its relationship to physics must begin with some metaphysical assumption in mind about the nature of conscious experience, the nature of matter and the nature of the relationship between them. These days the most prominent metaphysical fixed points are strong emergence or some variant of panpsychism. In this paper we will detail another distinct metaphysical starting point known as neutral monism. In particular, we will focus on a variant of the neutral monism of William James and Bertrand Russell. Rather than starting with physics as fundamental, as both strong emergence and panpsychism do in their own way, our goal is to suggest how one might derive fundamental physics from neutral monism. Thus, starting with two axioms grounded in our characterization of neutral monism, we will sketch out a derivation of and explanation for some key features of relativity and quantum mechanics that suggest a unity between those two theories that is generally unappreciated. Our mode of explanation throughout will be of the principle as opposed to constructive variety in something like Einstein's sense of those terms. We will argue throughout that a bias towards property dualism and a bias toward reductive dynamical and constructive explanation lead to the hard problem and the explanatory gap in consciousness studies, and lead to serious unresolved problems in fundamental physics, such as the measurement problem and the mystery of entanglement in quantum mechanics and lack of progress in producing an empirically well-grounded theory of quantum gravity. We hope to show that given our take on neutral monism and all that follows from it, the aforementioned problems can be satisfactorily resolved leaving us with a far more intuitive and commonsense model of the relationship between conscious experience and physics.
In recent decades it has become common throughout the social sciences to think of the human mind simply as a very complex computer. Drawing on an older materialist metaphor of the mind as a machine, the “computational” model of the mind took off after the mid-century invention of the computer and subsequent cognitive revolution in psychology, and has since permeated the social sciences in the form of rational choice and other prominent social theories. The contributions of this model have been huge; but it has always been assumed that the computations going on inside our heads are classical. Quantum brain theory challenges this assumption by proposing that the mind is actually a quantum computer. Classical computers are based on binary digits or “bits” with well defined values (0 or 1), which are transformed in serial operations by a program into an output. Quantum computers in contrast are based on “qubits” that can be in superpositions of 0 and 1 at the same time and also interact non-locally, enabling every qubit to be operated on simultaneously. The idea of a quantum computer was first proposed in the 1980s and is still far from being realized technologically, but it has fired the imagination of scientists by raising the prospect of unimaginable increases in computational power, and other neat tricks besides. If quantum brain theory is true, then our model of the mind would be similarly radically altered, irrespective of the issue of consciousness. Quantum brain theory hypothesizes that quantum processes at the elementary level are amplified and kept in superposition at the level of the organism, and then, through downward causation constrain what is going on deep within the brain. On this view, information from the environment is continuously transformed from the macro- to the micro-level, and then channeled back upward into an “internal quantum state,”
Despite scholarly consensus on the empirical facts, ever since its inception in the 1920s there has been deep disagreement about how to interpret quantum theory. “To interpret a physical theory is to say what the world would be like, if the theory were true.” All scientific theories require interpretation, since strictly speaking what they describe are our experiences of the world rather than the world itself. Thus, whether we are trying to explain or merely describe the world, we are always engaged in inference. To make inferences we need a context for interpretation. For any given claim this context is provided locally by related theories, more broadly by disciplinary paradigms, and ultimately by worldview claims about the nature of reality. The challenge in interpreting scientific theories is to integrate them into this hierarchy of knowledge. Usually this is not too difficult. New theories often require adjustments to nearby theories, but in doing so we can rely on paradigms to make them cohere. More rarely paradigmatic assumptions are themselves challenged, but in that case scientists can fall back on their worldview to make sense of the needed changes. By implication, the most difficult interpretive problems arise when our worldview is called into question, which leaves us without any frame of reference on which to fall back. Quantum theory poses a worldview problem. Prior to the quantum revolution the classical worldview could not be tested scientifically and so it was essentially metaphysical. Even though it corresponded to our experience of material objects, we lacked proof that it adequately represented the deep structure of reality. By giving us access to that deep structure for the first time, quantum mechanics made it possible to do such a test, or “experimental metaphysics.” Unfortunately, the results seemed to contradict classical assumptions, at least on the sub-atomic level.