Ken G said:Yet I see something that I regard as backward in Strawson and Russell's positions. They are asking, why can't mind emerge from material "stuff", if we know so little about the true nature of material stuff? The problem is, what we mean by "material stuff" is only what we know about it in the first place-- it is a model, not the actual stuff...
The specific problem I want to discuss concerns consciousness, the hard nut of the mind-body problem. How is it possible for conscious states to depend upon brain states? How can technicolour phenomenology arise from soggy grey matter? What makes the bodily organ we call the brain so radically different from other bodily organs, say the kidneys-the body parts without a trace of consciousness?...The mind-body problem is the problem of understanding how the miracle is wrought, thus removing the sense of deep mystery. We want to take the magic out of the link between consciousness and the brain."
You're right that the other thread might be more appropriate, but to complete this point, my interpretation of Russell/Strawson is that they are arguing that despite our tendency to be incredulous that material stuff could really act so profoundly, we should not be discouraged from trying to understand consciousness as emerging from a materialistic accounting of brain function. Their point seems to stand on the grounds that we don't understand what material stuff is actually capable of, so we should suspend that incredulity. My point was that the issue is not what material stuff is capable of, it is what material stuff is, or more correctly, how we think about material stuff. I'm saying that if we need to dramatically alter how we think about material stuff to give an accounting of what consciousness is, then we have already vacated the materialistic position, it doesn't make any difference what the new description of "material" looks like. Materialism doesn't mean a committment to always reassess the meaning of "material" to uphold whatever we need it to be, it means a committment to a given and present meaning of the term.bohm2 said:Well Russell/Strawson are claiming that on some level we don't know enough about matter/the brain to make any such claims. This seems like a perfectly reasonable argument.
ThomasT said:Then I'll check out Valentini's model more closely...As for Bohm's quantum potential...
Formalism, Ontology and Methodology in Bohmian MechanicsNext, Valentini claims that his interpretation of ψ as a ‘guiding field of information’ is “free of complications”. In claiming this, he evidently does not see the irreducibly multi-dimensional character of ψ as a “complication”. This point brings out an internal tension in his guidance view. He wants to interpret ψ (via the pilot wave S) in realistic terms as representing a physically real causal entity, yet he never expressly takes a stand regarding the status of the configuration space in which ψ exists. He introduces further ambiguity by equivocating upon the real physical status of ψ itself. While in one place he takes the view that “The pilot-wave theory is much better regarded in terms of an abstract ‘guiding field’ (pilot-wave) in configuration space...” , in another he states that “The quantum mechanical wave function ψ(x, t) is interpreted as an objectively existing ‘guiding field’ (or pilot-wave wave) in configuration space...”. Is ψ a concrete entity existing in a physically real space or is it only an abstract entity existing in a mathematical space? Valentini does, though, somewhat clarify his view elsewhere by stating that “the pilot wave ψ should be interpreted as a new causal agent, more abstract than forces or ordinary fields. This causal agent is grounded in configuration space...” .
Thus, the pilot wave or ‘guiding field’, while being more abstract than forces or classical fields, in the sense of being further removed conceptually from ordinary experience-the concept of ‘guiding field’ is achieved by abstracting the notion of ‘force’ from the classical concept of ‘field’, is nonetheless an objectively existing causal entity. But, that such an entity is grounded in configuration space implies that configuration space itself must be taken to be physically real in some sense. Whereas Albert takes an unequivocal (though perhaps incoherent) stand on this, Valentini leaves us without a clear idea of in what sense configuration space is to be regarded as physically real. Is configuration space itself the only physical reality? Or are both configuration space and ordinary space physically real? And, if so, are they real in the same physical sense? These questions remain to be answered for any interpretation of Bohmian mechanics that would postulate entities in configuration space.
So it's argued that Bohm's/Hiley's/Holland's version (e.g. with the quantum potention-Q) does not require one to draw some arbitrary distinction between the micro/macro-domain, since the classical limit is attained quite naturally: when Q/V <<<1, (where Q is quantum potential and V is classical potential) the quantum dynamical equation becomes the classical equation of motion so that "conceptually, a continuous passage from the microdomain to the macroworld is possible." Here's a graph of some of the different Bohmian interpretations and characteristics according to this author (Darren Belousek):Regarding the causal view, though, we should consider one further argument for retaining the quantum potential over the objections of the guidance view. Besides playing a key role in explanation, the quantum potential is also crucial for formulating the classical limit in Bohmian mechanics. One of the chief advantages of Bohmian mechanics over standard quantum mechanics is that the former can formulate the classical limit in a mathematically precise and coherent way. Thus, in deciding the very meaning of Bohmian mechanics itself, one should take the classical limit into account.
In the following table we summarize the five interpretations of Bohmian mechanics that we have considered, where each is appraised with respect to our desiderata of
(i) all postulated entities sould exist in 3-dimensional physical space;
(ii) the quantum state ψ should, in some way, be interpreted in physical (and not merely statistical) terms; and
(iii) the physical interpretation of ψ should adequately underwrite explanation of quantum phenomena
There are two related problems that immediately arise here. First, if both multi-dimensional configuration space and ordinary 3-dimensional space are to be equally physically real, then unless one spells out the physical relation between them, one will have divided the quantum world into two disparate realms. Second, if the quantum field (in whatever sense it is to be understood) exists in configuration space and particles move in ordinary 3-dimensional space, how is the quantum field to act causally upon the particles in order to guide their trajectories? Solving the second problem depends, of course, upon solving the first. One might reply to the first problem that ordinary 3-dimensional space can be regarded simply as a sub-space projection of the multi-dimensional configuration space.
But, for an N-particle system described by a 3N-dimensional configuration space, there are mutually orthogonal sub-space projections. Do we then have multiple disjoint ordinary spaces for each many-particle system, one for each particle? The significance of this situation can be brought out by considering the case of an N-particle system in a factorizable quantum state– ψ(q1, . . . , qN) = ψ1(q1) . . .ψN(qN). In contrast to the general case of a non-factorizable quantum state, in this case one can represent the system in terms of N ‘waves’, where ψi(qi) depends upon only the coordinates of the ith particle so that each ‘wave’ can be associated with a separate particle. But, the sub-spaces of the 3N-dimensional configuration space to which the respective ψi(qi)’s belong are all mutually orthogonal so that the N ‘waves’ and particles do not all exist in one and the same 3-dimensional space (unless one were to equivocate on the meaning of the qi ).
Thus, even in this case, one cannot simply regard the total quantum system as existing in ordinary 3-dimensional space, but rather must still regard it as existing irreducibly in configuration space, with each part existing in a ‘separate’ sub-space. And that would undercut any sense of a single system existing in one and the same physical space, which is surely requisite for a coherent physical theory.
Thy Mysteries of Nature: How Deeply hidden?Leibniz argued that Newton was reintroducing occult ideas similar to the sympathies and antipathies of the much-ridiculed scholastic science, and was offering no physical explanations for phenomena of the material world...Newton largely agreed with his scientific contemporaries. He wrote that the notion of action at a distance is “inconceivable.” It is “so great an Absurdity, that I believe no Man who has in philosophical matters a competent Faculty of thinking, can ever fall into it.” By invoking it, we concede that we do not understand the phenomena of the material world. As McMullin observes, “By ‘understand’ Newton still meant what his critics meant: ‘understand in mechanical terms of contact action’.”
“It was 40 years before Newtonian physics firmly supplanted Cartesian physics, even in British universities,” and some of the ablest physicists of the eighteenth century continued to seek a mechanical-corpuscular explanation of gravity—that is, what they took to be a physical explanation—as Newton did himself. In later years positivists reproached all sides of the debates “for their foolishness in clothing the mathematical formalism [of physical theory] with the ‘gay garment’ of a physical interpretation,” a concept that had lost substantive meaning.
Newton’s famous phrase “I frame no hypotheses” appears in this context: recognizing that he had been unable to discover the physical cause of gravity, he left the question open. He adds that “to us it is enough that gravity does really exist, and act according to the laws
which we have explained, and abundantly serves to account for all the motions of the celestial bodies, and of our sea.” But while agreeing that his proposals were so absurd that no serious scientist could accept them, he defended himself from the charge that he was reverting to the mysticism of the Aristotelians. His principles, he argued, were not occult: “their causes only are occult”; or, he hoped, were yet to be discovered in physical terms, meaning mechanical terms.
Newton not only joined the great scientists of his day in regarding “the now prevailing theory of actio in distans … simply as absurd, [but] also felt himself obliged, in the year 1717, in the preface to the second edition of his ‘Optics,’ to protest expressly against [the] view” of his followers who “went so far as to declare gravity to be a fundamental force of matter,” requiring no “further mechanical explanation from the collision of imponderable particles.” Lange concludes that “the course of history has eliminated this unknown material cause [that so troubled Newton], and has placed the mathematical law itself in the rank of physical causes.” Hence “What Newton held to be so great an absurdity that no philosophic thinker could light upon it, is prized by posterity as Newton’s great discovery of the harmony of the universe!”
Thus,It is further characteristic of these physical objects that they are thought of as arranged in a space-time continuum. An essential aspect of this arrangement of things in physics is that they lay claim, at a certain time, to an existence independent of one another, provided these objects ‘are situated in different parts of space’. Unless one makes this kind of assumption about the independence of the existence (the ‘being-thus’) of objects which are far apart from one another in space—which stems in the first place from everyday thinking— physical thinking in the familiar sense would not be possible. It is also hard to see any way of formulating and testing the laws of physics unless one makes a clear distinction of this kind. This principle has been carried to extremes in the field theory by localizing the elementary objects on which it is based and which exist independently of each other, as well as the elementary laws which have been postulated for it, in the infinitely small (four-dimensional) elements of space.
Einstein notes that in classical field theory all of the beables are local, and local in the strongest sense: the entire physical situation is nothing but the sum of the physical situations in the infinitely small regions of space-time.
Causal realismThe quantum potential acts on the quantum particles in determining their trajectory, but the quantum particles are causally inert: they do not in turn act on the quantum potential. But this fact constitutes a serious objection to the ontology of Bohmian mechanics. One can with good reason follow Bell in acknowledging the need for local beables. It is, however, questionable whether one respects the spirit of Bell’s demand in posing local beables that are hidden variables and that are causally inert, not manifesting themselves in any way.
Consciousness and SpaceHow do conscious events cause physical changes in the body? Not by proximate contact, apparently, on pain of over-spatialising consciousness, and presumably not by action-at-a-distance either. Recent philosophy has become accustomed to the idea of mental causation, but this is actually much more mysterious than is generally appreciated, once the non-spatial character of consciousness is acknowledged. To put it differently, we understand mental causation only if we deny the intuition of non-spatiality. The standard analogy with physical unobservables simply dodges these hard questions, lulling us into a false sense of intelligibility...
Conscious phenomena are not located and extended in the usual way; but then again they are surely not somehow 'outside' of space, adjacent perhaps to the abstract realm. Rather, they bear an opaque and anomalous relation to space, as space is currently conceived. They seem neither quite 'in' it nor quite 'out' of it. Presumably, however, this is merely an epistemological fact, not an ontological one. It is just that we lack the theory with which to make sense of the relation in question. In themselves consciousness and space must be related in some intelligible naturalistic fashion, though they may have to be conceived very differently from the way they now are for this to become apparent. My conjecture is that it is in this nexus that the solution to the space problem lies. Consciousness is the next big anomaly to call for a revision in how we conceive space-just as other revisions were called for by earlier anomalies. And the revision is likely to be large-scale, despite the confinement of consciousness to certain small pockets of the natural world. This is because space is such a fundamental feature of things that anything that produces disturbances in our conception of it must cut pretty deeply into our world-view...That is the region in which our ignorance is focused: not in the details of neurophysiological activity but, more fundamentally, in how space is structured or constituted. That which we refer to when we use the word 'space' has a nature that is quite different from how we standardly conceive it to be; so different, indeed, that it is capable of 'containing' the non-spatial (as we now conceive it) phenomenon of consciousness
Ken G said:It won't surprise you that I view the resolution of this kind of question to lie in the recognition that neither consciousness, nor any other more clearly physical phenomenon, "exists in" either real space or configuration space. Rather, the connection is the other way around-- the action of our intelligence, related to consciousness in some still mysterious way, is to take our sensory inputs and our efforts to organize and predict them, and insert them into conceptual frameworks we call real space and configuration space. That much is demonstrably true, it is very clear that we do exactly that, the question is can we correctly imagine that there is some other more fundamental meaning to these versions of space? I can't see any reason to think so, I can't see how the description I just gave is missing anything that could ever be established to be true by any scientific or even philosphical argument. To expect space to mean anything else is to mistake an effective ontology for a real one, but the latter concept is just a fantasy or pipe dream.
The ontology of Bohmian mechanicsThe spatial configuration of a universe of N particles at time t is represented by a vector Q(t) ∈ IR3N. This vector can be regarded as a point in configuration space, but represents the actual configuration of the particles in three-dimensional physical space. The 3N-dimensional configuration space is usually understood as the mathematical representation of all possible configurations of N particles existing in three-dimensional physical space. Regarding the universal wave-function as a complex-valued function Ψ(x), the variable x then ranges over all possible spatial configurations of the universe. A tension now arises when this function is supposed to represent a physical field, existing as a concrete entity in the actual physical world. Then, one either has to argue that the space of possible configurations somehow supervenes on the actual configuration of the particles in physical space, or grant it an independent reality in addition to three-dimensional physical space. The dispositionalist, by contrast, has no such troubles. In being located in a certain manner in three-dimensional physical space, the particles have the disposition to move in a certain way...In short, there is a disposition for a certain form of motion as a property of the particles instead of a field or a pilot-wave external to the particles that is supposed to move them. Nonetheless, it may seem that the dualism of entities has simply been replaced with a dualism of properties...There is no problem of connection of the various properties admitted in the ontology, if all elements of the ontology are located in physical space and, moreover, if all properties are properties of the particles. In other words, even if there is a dualism of properties, it does not give rise to the objections that hit the dualistic ontology of particles in physical space and a field on configuration space.
I read that article before and had trouble understanding it but they seem to be arguing for the claim that three-dimensional objects exist emergently, given the 3N-dimensional ontology. They write:Quantumental said:I find this paper by Wallace and Timpson interesting: http://arxiv.org/abs/0907.5294
In it they argue against configuration space wf realism and for what they call space time state realism.
And I'm guessing emergence would occur via decoherence? But as I understand it, decoherence cannot do that. Monton has also criticized Wallace's/Timpton's arguments for other reasons. He writes:While the wave-function realist will deny that 3-dimensional objects and spatial structures find a place in the fundamental ontology, this is not to say that the 3-dimensional objects surrounding us, with which we constantly interact, and which we perceive, think and talk about, do not exist, that there are not truths about them. It is just to maintain that they are emergent objects, rather than fundamental ones. But an emergent object is no less real for being emergent...It is also worth keeping in mind that many workers in quantum gravity have long taken seriously the possibility that our 4-dimensional spacetime will turn out to be emergent from some underlying reality that is either higher-dimensional (as in the case of string theory) or not spatio-temporal at all (as in the case of loop quantum gravity). In neither case is it suggested that ordinary spacetime is non-existent, just that it is emergent.
Against 3-N Dimensional spaceBut it’s not clear from Wallace and Timpson’s discussion what’s meant to ground the claim that three-dimensional objects exist emergent...Maybe Wallace and Timpson hold that there’s something special about the structure of the wave function in 3N-dimensional space that gives rise to three-dimensional objects, even in a world where there’s no experience at all. I have two responses. First, I’d need to see the argument. Second, I don’t think one could provide a sound argument for this, because reality doesn’t work that way. It’s simply not the case that one can have a 3N-dimensional space with a field evolving in it, such that when the field has a certain configuration three-dimensional objects come into existence. Granted, this isn’t logically impossible–there could be laws of physics that specify the conditions under which three-dimensional objects come into existence–but for them to come into existence emergently, without this happening in accordance with certain novel laws of physics, is not the way a world where quantum mechanics is true works.
https://www.physicsforums.com/showthread.php?t=285019In the end, there is no precise way of telling if this should be a one particle in a 3N-dimensional space, N particles in a 3-dimensional space, or 3N particles in one dimension.
bohm2 said:And I'm guessing emergence would occur via decoherence? But as I understand it, decoherence cannot do that.
Thanks for the link. He does reference (see reference 55) Maudlin's article we discussed. But I know you didn't find that argument convincing.Quantumental said:But why not? I know that Tim Maudlin objects to it, but I've seen very few others with the exception of Amit Hagar's recent paper: http://rsta.royalsocietypublishing.org/content/370/1975/4594.full.pdf
Quantum Structures of a Model-Universe: Questioning the Everett Interpretation of Quantum MechanicsIn simplified terms: the Everett worlds splitting (branching) is not allowed for the realistic Everett worlds. Thus, we conclude: Unless there is a privileged, spatial structure (decomposition into subsystems) of the model-universe, Everett Interpretation appears either to be not correct or the Everett-worlds (the Everett ”branches”) are not physically real. The interpretational consequences as well as some ramifications of our findings are yet to be explored.
The Status of our Ordinary Three Dimensions in a Quantum UniverseThere are now several, realist versions of quantum mechanics on offer. On their most straightforward, ontological interpretation, these theories require the existence of an object, the wavefunction, which inhabits an extremely high-dimensional space known as configuration space. This raises the question of how the ordinary three-dimensional space of our acquaintance fits into the ontology of quantum mechanics. Recently, two strategies to address this question have emerged. First, Tim Maudlin, Valia Allori, and her collaborators argue that what I have just called the ‘most straightforward’ interpretation of quantum mechanics is not the correct one. Rather, the correct interpretation of realist quantum mechanics has it describing the world as containing objects that inhabit the ordinary three-dimensional space of our manifest image. By contrast, David Albert and Barry Loewer maintain the straightforward, wavefunction ontology of quantum mechanics, but attempt to show how ordinary, three-dimensional space may in a sense be contained within the high-dimensional configuration space the wavefunction inhabits. This paper critically examines these attempts to locate the ordinary, three-dimensional space of our manifest image “within” the ontology of quantum mechanics. I argue that we can recover most of our manifest image, even if we cannot recover our familiar three-dimensional space.
bohm2 said:Even though I don't find her functionalist argument persuasive, this is a very interesting paper discussing whether we can recover 3-space from configuration space and if we can't what it means:
The Status of our Ordinary Three Dimensions in a Quantum Universe
http://www.rochester.edu/college/faculty/alyssaney/research/papers/Ney_3DQM.pdf
Her major argument is a functionalist one. Although she doesn’t seem to commit herself to Wallace’s or Albert’s version. She writes:Quantumental said:I don't see any functionalist argument here, all she does is mention that "if through functionalism it works, then it might be enough to describe our experiences"".
But I still don’t buy her argument for some of the same reasons mentioned by Monton and others. I don’t, however, agree with Monton that the wave function/configuration space is just some sort of illusion. I think both spaces and ontologies (wave function and particles) do represent something that exists in the world but not in the minimalist way argued by Maudlin/DGZ where the wave function is treated as a law.How does this work? We begin by being functionalists about the material objects of our manifest image–all that is required for there to be a chair is for there to be something that can play the functional role of a chair. For there to be a person, there just must be something that can play the functional role of a person. Albert suggests that any physics that is going to have a chance at describing our world as we experience it is going to have to describe a wavefunction that evolves in such a way that it is able to play the functional role of a universe with tables and chairs and people in it (1996, pp. 279-280)...
The idea is this. Accept the straightforward, ontological reading of these realist versions of quantum mechanics. In other words, accept that all there is fundamentally is a wavefunction in configuration space. Then the claim is that in the actual world, the behavior of the wavefunction over time is such that it is able to play the functional role we ordinarily associate with material objects in a three-dimensional...
I am claiming that while functionally-enacted chairs are chairs, and functionally enacted people are people, for a substantivalist, functionally-enacted space is nothing more than a simulation...We can allow that the fundamental space of quantum mechanics is the high-dimensional configuration space, but also claim that there is a derivative, functionally-enacted three-dimensional space occupied by tables, chairs, and people.
What is a wavefunction?The fact that the quantum wavefunction of a many-particle system is a function on a high-dimensional configuration space, rather than on spacetime, has led some to suggest that any realist understanding of quantum mechanics must regard configuration space as more fundamental than spacetime. Worse, it seems that a wavefunction monist ontology cannot help itself to talk of "configuration space" at all, without particles for the configurations to be configurations of. The wavefunction, it might seem, threatens to become a function defined on a high-dimensional space whose relation to spacetime is obscure. I will argue that such worries are misplaced.
There’s also the problem of how an "informational field" can guide/interact with the particle, particularly because it can't be by any "mechanical" interaction (non-local). Moreover, the field acts on the particles but the particle doesn't act on the field. This goes against Einstein's action-reaction principle (Newton’s third law). Lee Smolin also criticizes this dualistic ontology on similar grounds:Finally, our model in which wave and particle are regarded as basically different entities, which interact in a way that is not essential to their modes of being, does not seem very plausible. The fact that wave and particle are never found separately suggests instead that they are both different aspects of some fundamentally new kind of entity which is likely to be quite different from a simple wave or a simple particle, but which leads to these two limiting manifestations as approximations that are valid under appropriate conditions.
So, is there a way to circumvent these problems? Seager suggests a Russellian/Eddington-type solution. Recall first, that Russell (and Eddington) argued that:This dependence is awkward because of a principle, which we can call the principle of explanatory closure: anything that is asserted to influence the behavior of a real system in the world must itself be a real system in the universe. It should not be necessary to postulate anything outside the universe to explain the physics within the one universe where we live. This means that the wavefunction must correspond to something real in the world. In the de Broglie-Bohm interpretation this is satisfied by asserting that the wavefunction is itself a beable. This results in a dual ontology-both the particle and the wavefunction are real. But this violates another principle, which is that nowhere in Nature should there be an unreciprocated action. This means that there should not be two entities, the first of which acts on the second, while being in no way influenced by it. But this is exactly what the double ontology of deBroglie-Bohm implies, because the wavefunction acts on the particles, but the positions of the particles play no role in the Schroedinger equation which determines the evolution of the wavefunction.
So basically physics can only tell us only about the relational/extrinsic properties of matter but has little to say about the intrinsic ground of such objects. Seager then suggests that perhaps Bohm’s model does give us a glimpse of the "intrinsic" properties of matter:Physics is mathematical, not because we know so much about the 'physical world' but because we know so little: it is only its mathematical properties that we can discover. For the rest, our knowledge is negative...The physical world is only known as regards certain abstract features of its space-time structure — features which, because of their abstractness, do not suffice to show whether the physical world is, or is not, different in intrinsic character from the world of mind.
So the core of Seager’s argument is that we know with absolute certainty that some macroscopic phenomena of the world are intrinsically mental even though we don't literally "see"/measure such phenomena. So if one cannot fathom how mental stuff can emerge from stuff currently described by physics, it is tempting to speculate that the intrinsic nature of the basic constituents of the world must have some vestiges of some property that allows for the possibility of emergence of mind at the macroscopic level:Hiley frequently expresses the distinction between active information and Shannon information as the latter being ‘information for us’ whereas the former is ‘objective information’ . Shannon information is ‘for us’ in the sense that we must always interpret the information structures or ‘signals’ in terms of some meaning we interpretively impose on some physical process. But at some level, interpretation must give out. That is, Shannon information requires some intrinsic grounding. Active information can thus be seen as playing the role of the intrinsic ground for the purely structural features of Shannon information. What exactly active information is remains somewhat mysterious. The quantum potential is the direct structural reflection of it in our world but that—of course—says little about its intrinsic nature. It is tempting to link active information with consciousness if only for the reason that conscious states seem to carry meaning intrinsically (as intentional content), and nothing else we know of does so. Such a view is at odds with the claim that the implicate order is neither mental nor physical however.
So whereas Bohm/Hiley have an interaction problem of how the wave function which lives in configuration space can interact with the particle evolving in 3-space, Seager treats the wave function as the intrinsic part a single entity.It is indeed the case that mind cannot emerge from scientifically described extrinsic properties like mass, charge, and spin, but do we know that mind could not emerge from the intrinsic properties that underlie these scientifically observable properties? It might be argued that since we know absolutely nothing about the intrinsic nature of mass, charge, and spin, we simply cannot tell whether they could be something non-mental and still constitute mentality when organised properly. It might well be that mentality is like liquidity: the intrinsic nature of mass, charge and spin might not be mental itself, just like individual H2O-molecules are not liquid themselves, but could nevertheless constitute mentality when organised properly, just like H2O-molecules can constitute liquidity when organised properly (this would be a variation of neutral monism). In short, the problem is that we just do not know enough about the intrinsic nature of the fundamental level of reality that we could say almost anything about it. Finally, despite there is no ontological difference between the micro and macro levels of reality either on the intrinsic or extrinsic level, there is still vast difference in complexity. The difference in complexity between human mentality and mentality on the fundamental level is in one-to-one correspondence to the scientific difference in complexity between the brain and the basic particles. Thus, even if the intrinsic nature of electrons and other fundamental particles is in fact mental, this does not mean that it should be anything like human mentality—rather, we can only say that the ontological category their intrinsic nature belongs to is the same as the one our phenomenal realm belongs to. This category in the most general sense is perhaps best titled ‘ideal’.