The discussion centers on the ontology of configuration space in quantum mechanics (QM), exploring its implications for understanding reality, particularly in relation to multi-particle systems. Participants examine various philosophical interpretations and models regarding the nature of configuration space and the wave function, considering both theoretical and conceptual aspects.
Participants do not reach a consensus, as multiple competing views regarding the nature of configuration space and the wave function are presented, with ongoing debate about their implications and interpretations.
Limitations include unresolved assumptions about the nature of dimensionality in configuration space, the implications of different interpretations on physical reality, and the complexities introduced by additional structures in the models discussed.
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’.