[Stan (question to Henry)]:
Do you still think nonrelativistic vN and Bohm can give different predictions for human decisions?
[Basil J. Hiley]:
I have a problem with this question. Where does vN say anything about 'human decisions'? When you use vN I presume that you are referring to vN's last chapter in "Mathematical Foundations"
As we all know vN sets up two processes, P1 the non-causal 'collapse' and P2 the causal evolution of the wave function via Schrödinger's equation. We must then find some criteria for deciding when to replace P2 by P1. This is equivalent to asking, "Where precisely do we put the 'Heisenberg cut' between the observed system and the observer?"
For Heisenberg P1 occurs at the point where 'potential' is transformed into 'actual'. This is a 'happening'. He writes "If we want to describe what happens in an atomic event, we have to realise that the word 'happens' can apply only to the observation, not the state of affairs between two observations."(Physics and Philosophy p. 54) Thus for Heisenberg the 'happening' is where the 'possible' becomes the 'actual' i.e., where P2 is replaced by P1.
But exactly where do we put this cut? vN shows it doesn't matter as long as there is one somewhere. He shows that you can put the cut at the level of the pointer or you can even put it as far down the chain as the visual cortex; the position makes no difference to the final outcome. This is what he refers to as the "principle of psycho-physical parallelism".
But if you do put it in the visual cortex, does imply that the mind can influence or even determine the result of a measurement? In other words does QM introduce an element of subjectivity into physics? Heisenberg is very clear here. He writes, "Certainly quantum theory does not contain genuine subjective features, it does not introduce the mind of the physicist as a part of the atomic event"(PP p. 55).
While I conclude that vN comes to the same conclusion, his chapter 6 contains a curious statement. It reads, "Indeed experience only makes statements of the type: an observer has made a certain (subjective) observation; never any like this: a physical quantity has a certain value" (MFQM p. 420). Could this be where 'human experience' fits in?
I am not sure because earlier he explains what he means by the 'principle of psycho-physical parallelism'. It states "that it must be possible so to describe the extra-physical process of subject perception as if it were in reality in the physical world i.e., to assign to its parts equivalent physical processes in the objective environment, in ordinary space"(MFQM p. 419). Once again I find the words 'as if' rather curious. Nevertheless he goes on finally to conclude, "Therefore, the non-causal nature of the process 1 is not produced by any incomplete knowledge of the state of the observer,.."(MFQM p. 439)
Leaving aside the curious wording of some of the translated sentences, it seems quite clear that vN worked hard to exclude 'human decisions' playing any active role in quantum processes. Of course 'humans' build the apparatus to answer questions that they feel to be appropriate. In that respect vN and Bohm are no different. Furthermore they both use P2. Where they are different is that vN needs P1and hence the 'collapse' while Bohm has no need for a 'collapse'.
[Henry]:
In Bohm theory the Schroedinger equation holds, whereas the QZE causes it to not hold.
[Robert Neil Boyd]
Why does Henry say the Schrödinger equation does not hold for QZE. In UU we explain the QZE in terms of the Bohm interpretation so I am puzzled by this remark (p. 131-2). I need clarification.
[Stan]:
Basil, my question to you is whether you agree that human decisions could in principle be able to distinguish the two ontologies.
[Basil]
Unfortunately I cannot answer this question with a straight 'yes' or 'no'. The reason is quite simple. I have to know and understand what ontologies you are referring to. In the case of the vN label I presume you are referring to Henry's ontology based on an extension of Heisenberg's ideas.
Henry makes it quite clear that he is strongly influenced by Heisenberg and is building a quantum ontology by focusing on the notion of an 'actual event'**. In doing this he makes it quite clear that he is "introducing in this way a quantum ontology and thus departing from the purely epistemological stance of the strictly orthodox Copenhagen interpretations"(MMQM p.149)
**[Heisenberg writes, "Therefore, the theoretical interpretation of an experiment requires three steps; (1) the translation of the initial experimental situation into a probability function; (2) the following of this function in the course of time; (3) the statement of a new measurement to be made on the system, the result of which can then be calculated from the probability function"...."The second step cannot be described in terms of the classical concepts; there is no description of what happens to the system between the initial observation and the next measurement. It is only in the third step that we change over again from the 'possible' to the 'actual'." (PP p. 48)]
Henry then argues that this ontology based on actual events has two defects (MMQM p. 149). (1) It is a runaway ontology: "each actuality is defined only in terms of possible future ones, in a sequence that never ends". (2) "The omission from the description of nature of the one thing really known to exist: human thought." Henry then uses these to motivate his own approach.
For me this is very close to Wigner's view expressed in his article "Remarks on the Mind-Body question". There he writes "It is not possible to formulate the laws of quantum mechanics in a fully consistent way without reference to consciousness."(The Scientist Speculates, ed I. J. Good, 284, New York, Putnam, 1965). Henry is aware of this.
Henry then moves on to "exploit vN by assuming that in the alert brain, the main actual events occur at the point where a choice is made between alternative possible instructions in the top-level process" (p. 153). This is to be compared with "Heisenberg's assumption for inanimate objects that the actual event occurs only at a high level, where it chooses between states corresponding to macroscopically different actions of the object, such as the firing or non-firing of a Geiger counter." (p. 153)
I find the use of the words 'choice' in discussing the brain and 'it chooses' in inanimate matter curious. Who chooses; what chooses? No doubt Henry has an answer but I won't go into that here. All we need to note is that this is the point where human decisions enter the discussion.
Notice we are already beyond the orthodox quantum theory and entering an unknown realm where many details have yet to be worked out. Indeed a lot more needs to be done before any decisions as to the validity of the approach can be made. For what it is worth, I think it is a very legitimate approach and one that should be pursued.
Agreed. No apriori conceptions on how reality ought to be should be made. We must all be willing to get off our hobby horses.
Now I want to turn my attention to "Bohm". Again we have to be very careful here because there is considerable confusion as to what precisely "Bohm" means in this context. I will answer in terms of what we set out in "The Undivided Universe". The original aim of the 'causal interpretation' was to provide a description of what was going on between measurements. This was a direct challenge Heisenberg's contention, "If we want to describe what happens in an atomic event, we have to realise that the word 'happens' can apply only to the observation, not to the state of affairs between the two observations." (Physics and Philosophy p. 54.) I think there is no dispute now in the claim that the Bohm interpretation does provide one possible counter example.
Does the BI provide a physically intelligible interpretation? Bohm did not think his original '52 paper (causal interpretation) was good enough. He lost interest in this interpretation for about ten years during the sixties and seventies. The work of Chris Dewdney, Chris Philippidis and myself re-ignited his interest. In my discussions with him, the idea of interpreting the quantum potential as active information emerged and this fitted much more closely with his general philosophical outlook. Indeed he felt that these ideas had changed his perception of the theory.
We were now able to physically account for a number of features of the interpretation, including a resolution of the measurement problem, not in terms of the collapse of the wave function, but in terms of 'inactive information'. What we were able to show was that when our instruments could clearly distinguish between the final possible outcomes, the information contained in what is traditionally called the 'empty wave packet' no longer contributed to the motion of the system and thus became inactive. In mathematical terms the contribution to the quantum potential of the 'empty wave packets' could be SHOWN to be zero. In this context it should be note that the 'empty wave packets' carried no energy. The energy was merely 'potential' (potentia).
Our use of the notion of active information is a radically new idea and has little if anything to do with Shannon information. Shannon information is to do with channel capacity and carries no notion of 'meaning'. Our notion of information carries meaning not for us but for the system that responds to it. All of this is explained in detail in our book so I will not go further.
[Please note in this regard that our interpretation is very different from the interpretation presented in Durr, Goldstein and Zanghi under the heading of "Bohmian mechanics". They will have nothing to do with the QP even though it emerges DIRECTLY from Schrödinger's equation. I am unconvinced by their arguments for adopting this position.]
I heard Durr talk on this at the 1999 State of the World Forum. He seemed very obscure, but he was probably upset at the Cargo Cult New Age pseudo science talks on the same platform with him that Danny Sheehan set up. I can understand that! :-)
Now we can come to the issue central to your question. Having explained the use of information to account for physical processes in the inanimate world, we can now raise the following question. "Is there any relation between the notion of (active) information that we use to account for quantum processes, and the notion of (active) information that is necessary to understand brain function?" We felt that there were enough similarities to suggest such a connection but we need to explore this possibility further. Notice it is not a question of merely identifying the two processes. It is a question of finding the similarities AND the differences. Thus we are not advocating a direct application of Schrödinger's equation to parts of the brain. What we are looking for is a more general way in which information is being processed in the brain, while being guided by our understanding of the role of active information in the quantum domain. What we are doing is to bring together the mental and physical sides into one common structure.
In fact we argue that the notion of active information provides a bridge between the physical and mental sides of nature. This active information lies on both sides of the mind/matter divide. The information contained in thought also appears on the material side in form of neurophysiological, chemical and physical activity. Thus we can provided a conceptual link between the two sides. Our problem now is to see exactly how to fit them together in actual processes in the brain.
Notice the language I have been using so far is limited because I am starting from a division when there is no division. Our fundamental proposal is that mind and matter are merely different sides of the same indivisible process.
For Bohm and myself, this process is the 'holomovement', which is described through the implicate order. His papers entitled "Hidden variables and the implicate order" (Zygon, 111-124, 1985) and "A new theory of the relationship of mind and matter" (Phil. Psy. 3, 271-286, 1990) give a good idea of his thinking long these lines.
I have also been thinking about these matters and have been considerably helped by discussions with Paavo Pylkkanen, Karl Pribram and Peter Fenwick. For example Paavo and I have just finished a paper entitled "Naturalizing the Mind in a Quantum Framework" which will appear shortly. I won't go into details here but you can find some more information to specific references on my web page http://www.bbk.ac.uk/tpru/RecentPublications.
With this understanding of the respective positions adopted by Henry and myself, I can now provide an answer to your original question:
"Basil, my question to you is whether you agree that human decisions could in principle be able to distinguish the two ontologies."
The answer is clearly 'yes' because the ontologies are not fixed by quantum theory. We are both going beyond the quantum theory, and furthermore we are going beyond QT in different ways. Both of us have to define our ideas much more precisely before we can decide how different our respective theories are. That is in the future. Lets get on and explore!
Basil Hiley.