interview conducted by Mitja Perus
National Institute of Chemistry, Ljubljana, Slovenia

Basil J. Hiley
is of the Physics Department, Birkbeck College, University of London
and is the co-author of the ontological interpretation of quantum theory
with the late Professor David Bohm

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Mitja Perus: QM (quantum mechanics) has predictive power and is not in contradictions with experiments, but there are a lot of problems with fundamentals of QM. How do you see this situation?
BASIL J. HILEY: QM enables you to calculate the correct probabilities for given experimental situations, but I think we need more from science than just predictions. It is in this area that there are problems with QM. I am not the only one who believes this. Murray Gell-Mann said that we all know how to calculate, how to use QM, but none of us really understands what is behind the formalism, what it is saying about nature. That has to be answered in some way.

M.P.: There is a revival of Professor Bohm's and your ideas in last years, isn't it? Examples are Holland's book "The Quantum Theory of Motion - An Account of the de Broglie-Bohm Causal Interpretation of QM" and many others, your book "Undivided Universe", many articles, for example in New Scientist (February 27, 1993), Scientific American (May 1994), etc. Where are reasons for this?
HILEY: First of all, I think, the existence of collective works showing how much has been done on this alternative interpretation, which is called the de Broglie-Bohm interpretation, or as I would call it, the ontological interpretation. There is a great unease about quantum physics in general. Some of the experiments are reaching the level where you can observe the behaviour of individual quanta or individual particles etc. Point number two, there has been a through-examination of the Bell inequality and the various experiments that have arisen out of that. These show that QM has some non-local feature. This has created a lot of interest. There is also a crisis in attempts to quantize gravity. There are fundamental problems and we are more or less forced to say that we have not really understood QM properly. Maybe QM is limited and that is why we cannot unite gravity with QM. In general relativity the question of time, for example, is difficult to understand. So we must reexamine the foundations. I think, the books by Peter Holland, and by David Bohm and myself have suggested an alternative that might show a new way forward.

M.P.: Electron undergoes continuous transformation between its wave-like and particle-like aspects. How would you explain this double nature, perhaps using your notions of implicate and explicate order?

HILEY: I find the notion of continuous transformations between wave-like and particle-like aspects very confusing. No one actually observes the wave-like properties. What one observes is a statistical distribution of individual events. When one analyses it, it LOOKS as if one can account for the result by some wave-like feature. But we have never actually seen the wave-nature of the quantum. The results of experiments are discrete events, which can be explained if we assume the wave-like quality. The continuous transition between wave and particle becomes blurred, it is not smooth.
The de Broglie-Bohm interpretation is the only interpretation of QM that provides an ontology. If one looks at the position of Niels Bohr, and particularly the people who analysed Bohr, you get a feeling that Bohr has given us the most consistent interpretation of QM, but it is an epistemological interpretation. This arises, it is argued, because of the problem of separating the observed from the observing apparatus. John Wheeler has written to me saying that there is no ontological interpretation of QM, but we have shown that one is possible. Here it seems that you have to move away from mechanism into some kind of organism or organicism. In that context you can still maintain a particle with the wave influencing the particle. The wave now seems to have a new quality; it is like an informational field. But when you go to relativity, even this view becomes difficult to maintain. We are not sure whether there is a permanent structure of electrons and whether they are always following continuous traectories. So maybe something deeper is involved. The wave function approach was maintained because it managed to provide a KIND of ontology, but the individuality could not be fitted into the Cartesian category. There is a contradiction. David Bohm and myself were addressing the question of alternative categories for QM. In that context Bohm had the idea of implicate and explicate order. The particle now was a series of unfoldements from a more deeper structure which we call holomovement.

M.P.: Due to your interpretation a particle has simultaneously well defined position and momentum which are uncertain to us. In what sense might this claim be a negation of the Heisenberg uncertainty principle?
HILEY: Some people certainly take this claim as a negation of the uncertainty principle. And they are very puzzled. In non-relativistic QM we assume that there is a particle, that it has a definite position and momentum, but these are unknown to us. In order to determine its position and momentum, we have to bring pieces of apparatus to bear on the particle. We have a beam of particles coming in, and we have to find the position of one of them. One way to do this is to put a slit in front of the beam. There is an uncontrolable change of momentum between the slit and the particle that comes through the slit, so consequently the momentum before the measurement is now not the same as the momentum after the measurement. We actually have to participate in the process of measurement and we have to transform the process we are examining. We and our instruments play an active role in the quantum processes. It is in this way that the uncertainty principle comes back again into the ontological interpretation. So it is not a negation of uncertainty principle; it is an explanation of how the uncertainty principle arises.

M.P.: So we have to distinguish the epistemological aspect of uncertainty principle and the ontological aspect of it?

HILEY: Yes. In fact, I prefer to look it at two levels: We have got a level of the actual entity. John Bell called this the "beable" level, the level at which we say that things are actually what they ARE. Then we have another level, called the observable level - the epistemological level. Thus there is an ontology underlying this level. It is not to say that the ordinary interpretation is wrong. The ordinary interpretation is confined at the level of observables, and then adding that there is nothing beneath it. Whereas we are saying that we can explain appearances from a deeper underlying ontology. (One could say reality, but one has to be very careful in using that word!)

M.P.: What are so called "hidden variables" and what role do they have? Would you give some examples? During our discussion in London you said that you dislike the word "hidden variables". Why? What second word would you suggest?
HILEY: Yes, I feel very uneasy by the word "hidden variables" for two reasons. Firstly, the word was coined, I think, by von Neumann in his book "Mathematical Foundations of QM". He constructed a proof saying that if there were additional parametres (if there was an underlying ontology) then QM could not be re-derived with their help. Thus you would not get agreement with experiments if you introduce these parametres. They became known as "hidden variables" and this term is automatically associated von Neumann's theorem. Now we know that von Neumann's theorem is wrong, not because anything in proof is wrong, but because of the assumptions he made. He was only talking about a very limited type of additional parameters.

Second, if we look at the ontological interpretation, we find that there are no additional parameters, we only have momentum and position. Therefore, when we use the word "hidden parameters", one might think that there is some additional structure which one has to use. But there is not. The reason why David Bohm in his paper called them "hidden" was because they are hidden in the sense the position and momentum are not simultaneously known to us: you cannot observe them directly together. To observe them you have to change the situation, to participate.

I prefer the more neutral word "beables" coined by John Bell. Here we have a new situation. It comes from an ontology which works. It does not add any new parameters. So if we just call momentum, position, angular momentum etc. "beables", then we do not need any exotic new type of strange parameters. The classical variables are used, but in a different way.

M.P.: Would you then explain what beables are?

HILEY: Beables are just those properties that the particle actually posesses independently of our measurements.

M.P.: So, including position and momentum, but without involvement of observer. That would be the intrinsic momentum?

HILEY: Yes, something intrinsic to the particle that can have these properties - that is "being". That is, where the word comes from - from "to be". It is what is. What we see are the appearances, and we have to explain these appearances in terms of what IS. Therefore the intrinsic properties that we attribute to the particles are called beables.

M.P.: Beables are some characteristics on this ontological level, not epistemological.

HILEY: Yes, precisely. They are variables that we need to make the ontology into a coherent whole.

M.P.: Are they attributed to particles or to fields? nbsp;

HILEY: Both.

M.P.: You say that "hidden variables" or, better to say, beables are non-local? What does this mean?
HILEY: Let us consider a simple case when we have two particles. Then you have as "beables" position and momentum of both particles. They are parameters associated with the local particle. But it is not possible to explain results of experiments without introducing a connection or some sort of interaction between two particles. If QM is STRICTLY true, then that connection is INSTANTANEOUS. In the ontological interpretation at this level there is some instantaneous action-at-a-distance. That is the non-local feature. So, it is not that the parameters are non-local. It is the coupling between them that is instantaneous and therefore non-local. So, we have non-local "hidden variable" THEORIES.

M.P.: What puzzles me here is the following: You say that "hidden variables" are non-locally instantaneously CONNECTED. It sounds that they themselves can even be local.

HILEY: Yes, this is a very interesting question. You make the assumption in the Bohm ontological interpretation that particles are centres of activity in the holomovement and these centres of activity are in different spatial positions.

In the ontological interpretation you have a particle and a wave. The wave is not something that is independent of the particle. They are two facets of the same process. Therefore you are right in asking, can we actually separate the two? The reason why we go to implicate order is because strictly at the deeper ontological level they should not be separated, but at one level it is possible to see these two entities as separate. So it is as if they are together, yet somehow spatially apart. It is very difficult to find words to describe it at this level unless you go into deeper questions of the implicate order. Maybe the categories that we are still using are inadequate...

M.P.: You also said that you dislike the notion "subquantum medium". I understand that such division into lower and higher levels is artificial, but we need some concepts for the sake of analysis. How would you solve that problem?
HILEY: "Subquantum medium" was in fact the way in which de Broglie and Jean-Pierre Vigier talk (he feels this medium is actually the reality). Here I recall the early discussions of the role of an ether for electro-magnetic phenomena. The conclusion was that we do not need an ether - the vacuum would do. What Einstein actually said was that we did not want to explain the electro-magnetic ether in terms of mechanical properties of a substance. I see that people now, forgetting Einstein's remarks, want to provide a MECHANISTIC subquantum medium; they want to keep Cartesian categories and that is wrong direction.

In quantum field theory there is the concept of vacuum. Normally people would say: Vacuum means that it is nothing there. But then you find that there are terms like "inequivalent vacuum states", vacuum fluctuates etc. What does it mean to have inequivalent nothingness? It is either nothingness or it is something. So, the idea is that the vacuum in fact is not empty. It maybe "full". We see these notions as vacuum polarisation in which virtual positron-electron pairs are created from the vacuum.

It looks as if the vacuum state is not empty, but that it is a medium of some kind. Einstein said: "I did not ban the 'quantum ether', but I do not want it to have mechanical properties." Now, if you remove the mechanical notion, then I see no harm in reintroducing the notion of the subquantum medium. But it has got to be a medium which is much subtler than a mechanical medium. Indeed, I believe, there is some deeper underlying process that we have not begun to understand yet.

M.P.: This underlying process you call holomovement?

HILEY: Yes, that can be thought of as a subquantum medium, if you like. Only I do not like the word medium, because of its mechanical connotations. There is something, but it is going on so fast that we cannot discriminate, we cannot pick out any detailed features of it yet. The invariances are dissolving far too quickly for our instruments to catch them. This fast activity we call holomovement.

M.P.: In your interpretation you take processes (not some elementary particles) as basic. But some people would say that processes are composite non-elementary phenomena arising from a disequilibrium between more elementary features, wouldn't they?
HILEY: Yes, but that is then going back to the reductionist philosophy. I feel that the non-locality in QM is telling us that we have to abandon reductionism. The idea of a holistic approach does not come only from the ontological interpretation of David Bohm. If you read Niels Bohr very carefully, you find terms like "wholeness of experimental conditions", "wholeness of phenomena", implying that you cannot analyze things. Bohr was right on this point. This holistic feature is revealed in the ontological interpretation as non-locality.

There is a wholeness in quantum processes which we cannot explain. There seems to be a contradiction between particles being together and yet apart in space. So, if we have a situation where we require some sort of holistic description, then we have to start with some sort of basic elements which we cannot subdivide further. Because if we are going to subdivide them by saying a process is made of subprocesses which, in turn, are made of subprocesses etc., then you are just going on the reductionistic route again. It is not possible to analyze a fundamental process in terms of anything deeper without changing it radically. That is why Niels Bohr told us that there was no sharp distinction between the observer or the observing instrument and the observed. If you try to interact with it to get more information about it, you change the whole experimental conditions and therefore you change the phenomena. So we have to stop trying reductionistic explanations of quantum processes.

M.P.: It borders me here that you are emphasizing the holistic nature of holomovement, but at the same time holomovement is a notion that replaces vacuum. It seems that what was completely empty for us before is now filled with something. Are we responsible for this - for breaking the symmetry of the vacuum - in measurement, but also conceptually?

HILEY: This is a very deep question: if we are in a holistic nature, how can we have partial views, how do we split this whole into a situation where we can actually talk about it at all. In order to handle this within the notion of implicate order David Bohm introduced idea of explicate order. Within implicate order it is always possible to find special types of explicate orders which display certain aspects of the holomovement. Then it is no longer possible to display "everything".

The observer becomes one "pole" and the process another "pole", but this is only an approximation; really they are still parts of the same total process.

M.P.: What is the role of algebras in mathematical formalising the notion of implicate order?
HILEY: Being a theoretical physicist I feel very unhappy with general concepts unless I can find some mathematical structure in which I can handle these concepts. When we were exploring how to find mathematics for implicate-explicate order relationships I was many years ago directed to a paper by Hamilton with a title "Algebra as pure time". In reading that paper it seemed to me that algebraic elements are the elements by which you can describe process. Grassman had a similar approach. He said: mathematics was about thought. It was about the FORM of thought, not its CONTENT. When you are talking about thought you are talking about becoming, not about being. How does a new thought arise: is it independent from the old thought or does it have a trace of the old thought? Does the old thought have the potentiality of the new thought? This process between the old and the new thought is continuous and you cannot make a subdivision. Grassman began to develop a mathematics using two-point entities. This investigation finally lead to what we now call Grassman algebras. In Clifford's hands algebra became associated with active movements - rotations, translations and so on. Algebra is catching the essence of movement and while looking at different aspects of algebra you might be describing PROCESS rather than things moving in space and time. QM can be completely put into an algebraic form. That is the Heisenberg matrix approach. This is why I am interested in algebras and it seems to be very promising.

M.P.: You say that the wave function is not a state function. Why not?
HILEY: All problems with the interpretation of QM arise because of the attitude that people adopt to the wave-function. If you regard it as a state of something, we have all the paradoxes - the "Schroedinger cat" paradox, the collapse of the wave-function etc. If I adopt an ontological standpoint, I will say that psi is really something I can attach to the object I am looking at. But it does not describe the object completely - it is the most complete description of the state of the system we can find.

What surprised me is that Bohr never mentions a measurement problem in any of his writings. If you read him carefully, he does not regard psi as a state-function. For him it is merely a part of an algorithm from which we can calculate the probable outcomes of given experiments. You see why he did not want to associate wave-function with the state of the system, because he said, you cannot separate the observed system from the observer. What does it mean to attach the label to something which you cannot distinguish from a background? If you then say that this is merely a part of an algorithm, then there is no collapse problem, because there is no STATE-function. That is why I said earlier that Niels Bohr has the most consistent interpretation of QM. But there are problems with Bohr, because he assumes that classical world exists. In modern cosmological theories, where the cosmos was created in a quantum event, there is no classical world. Therefore a reexamination of what QM really means is necessary.

In Bohm's ontological interpretation there is a different attitude adopted towards psi. There it is considered to be a REAL field or two coupled real fields. In this case all the quantum paradoxes disappear! You do not get the measurement problem, you do not get the "Schroedinger cat" paradox etc. Each of these three interpretations has its own sets of problems. Which is the correct one? Are any of them correct? All three are inadequate in some way and we will have to go beyond them. We have not got right categories in which to understand quantum phenomena and we should all be searching for new categories. One proposal is through implicate order.

M.P.: What is a particle due to your opinion?
HILEY: On what level?

M.P.: Would you compare the ontological level and the epistemological level, with emphasize on ontological level, because epistemological is known better?

HILEY: In the Bohm's ontological interpretation, which has been well worked out, it is assumed that the particle has some centre, some kernel. There is some local centre to this whole process which we describe by means of a field and a particle. Using the implicate order idea we could think of the particle as some sort of outward manifestation of some total unfolding-enfolding process. Particles would merely appear to be as "ripples on the surface of water". We just see the "surface". You once said that we just "see the top of the ice-berg". But really they have a lot of structure underneath. Those "ripples" are what would be particles in the holomovement. They have not been further analysed. They are some quasi-stable semiautonomous features of this background process.

M.P.: What does the notion of "field" means to you, and what is the connection between the field and the particle?
HILEY: A conventional physicist might say, we can get rid of particles - really everything is done through fields. My worry is that this is the very thing that has caused all the troubles in general relativity when we tried to quantize it. To describe the field, we need the space-time manifold and we need it to be classical. Now general relativity shows deep connection between the gravitational field and the space-time manifold. If the gravitational field is quantized, the field fluctuates, therefore space-time fluctuates. What is the meaning of the field, if the very structure in which we place the field is fluctuating and "tearing"? The notion of field disappears in that context. Therefore even field theory is not sufficient and we have to go to processes, not processes in space-time, but the process from which space-time will be abstracted.

M.P.: It seems that a particle, let us say an electron, is a very complex structure. In what sense? Internally - as a complex system (or "configuration") of "hidden variables" or "beables"? And externally - as an element which is involved in a complex collective behavior of the field as a whole, and is so co-determined by its environment which acts as a complex system?
HILEY: Most physicists take electron as being a point-like particle. In experiments which have been made to find the radius of the electron they assume that it has an internal structure which they describe by a form-factor. They do scattering experiment and then they see what this form-factor is. They find no structure. So, if the electron has a radius, it is less than 10e-15 cm. The natural assumption is that it is point-like.

But it seems very difficult to understand how a point can process the information of its own field coming back from environment. Therefore in the ontological interpretation we postulate that there should be some structure between 10e-15 cm and 10e-33 cm which is the Planck length. This is where people think that space-time will break down (I feel it may break down before that). There are many orders of magnitude between present-day experimental limitations and the Planck length, so there is room for a deeper spatial structure. But then we go to the implicate order where the electron is viewed as some form of coming together of energy which dissolves again, comes together again and so on. This is not in space-time. You can have a structure in electron without being extended in space-time. But the question as to what this structure is, is something for future research.

M.P.: I mentioned in the question also another possibility, that properties of an electron are given by his role in the whole system...

HILEY: I think that is true. The particle is a much more complex structure which involves both the environment and itself. It is a correlation between these two aspects that is important.

M.P.: How do you see the bootstrap theory?
HILEY: That is Jeffrey Chew's idea which is in some way related to the last question that everything determines everything else. If you have a holistic situation and if you make one part of it explicate, then the other part becomes implicate, but with this you can explicate another aspect... There is a kind of bootstrapping in this.

Chew's idea was that every particle is a composite of all the other particles. There are no fundamental particles. In general terms, it is the same idea; but in particular, the bootstrap theory of particle physics was just trying to question whether there is any set of basic particles. It is not a relevant question for the implicate order, because it is fundamentally about PROCESSES. The invariances in this process are the particles. Particles are not made up by another particles, but are invariant features of the holomovement. So, they would not be made of each other, they would be aspects of this general process. There are some similarities, but there are also some differences with the bootstrap theory.

M.P.: Quantum potential depends on the quantum state of the whole system in a way that cannot be defined simply as a pre-assigned interactions between all the particles. It depends on the many-body wave-function which evolves according to the Schroedinger equation. How does the quantum potential depend on the whole many-body system?
HILEY: If you presuppose subquantum medium (in spite of problems which we were talking about before), then you might be able to transmit non-local interactions through this subquantum medium. You might say that whenever a particle or a set of particles were at some particular positions in space-time, then some disturbance of this medium is responsible for coordinating the movements of particles involved in this many-body wave-function. But by saying that you cannot have a pre-assigned wave-function, we mean that you may have another set of particles with another non-product wave-function in the same region of space as the first set of particles, and they have an entirely different behaviour. It is not possible to find a subquantum medium that could produce an effect so that both sets of particles behave in a different way. In the same region of space-time one set of particles behaves in a totally different way from the behaviour of the other set of particles. That is why you cannot have a field, which is correlating the particles, as a pre-assigned function of position... Because they are at the same points, but they behave differently at those points in space. There is no pre-assigned function that will do that.

The quantum potential comes out as being non-local, simply because the wave-function is non-local. The wave-function is a function of a particle at position one, position two, position three etc. at the same time. The quantum potential can be calculated from that, therefore the quantum potential must be at position one, two, three etc. at the same time! This particular description makes it non-local, instantaneous. In the deeper theory the quantum potential arises as an appearance from the deeper levels - implicate order and holomovement.

M.P.: You claim that the quantum potential is an information potential. What is here the difference between force (or interaction) and information?
HILEY: In classical physics the amplitude of a field, which gives rise to a potential, is directly related to the intensity of the force. While swimming in the sea, if the waves are very small, then you experience a very small effect. But if the waves have very high amplitudes, you will experience very big effect. So, the amplitudes of the wave determines what will happen. That is classical pushing and pulling.

On the other hand, the force that you get through the quantum potential is independent of the amplitude of the field. This means that you can have a very big amplitude and a very small force, or you can have a very small amplitude and a very big force. Small amplitudes are used in radio-signals, for example: the audio-frequencies are carried on radio-wave. Very small signals are then amplified by the radio-set, and out comes the normal sound. By the radio-signal we carry information.

We are suggesting that the electron processes the information on the wave by looking at the rate of the rate of change of the amplitude. So there is no need for the force to fall off as an inverse square of the distance (as is true for many classical forces). This wave can carry non-locality, because it requires only very little amplitude to carry these signals. We are suggesting that the field that gives rise to the quantum potential is an information field. This is not an information field in the way that the radio-signal is information for us, rather one has to look at the actual meaning of information. It means literally to form from within - to "in-form". The energy for the loudspeaker comes from the battery (here we can still use analogy with the radio), from within the radio itself. In the case of an electron, this energy comes from the electron itself, so that it can change its motion and respond to the information in the signal. We are using the quantum potential as a carrier of information, rather than a classical push-pull force. So it is not only a different force, but it is also a radically different quality of force. It should be stressed that this information is not the Shannon information that is used in communication, it is a different kind of information.

M.P.: Where does the electron get energy in order to respond to this information?

HILEY: It comes from within, but it can also come from the vacuum (holomovement).

If there is a stationary state, total energy is conserved and there is swapping of energy between the kinetic energy, the classical potential energy and the quantum potential energy - taking one kind of energy and giving back another form. But that all comes from within the electron itself. In a way it is like a self-organization. Electron is organizing itself, because the field which is part of the electron, is inseparable from the electron itself. So we are suggesting that self-organization is present at a very basic level.

M.P.: You are introducing also a second new notion - superpotential (governed by a Schroedinger superwave equation) that is in instantaneous (i.e. non-local) contact with all particles. What does this mean?
HILEY: We naturally have to extend non-relativistic QM into the relativistic domain, otherwise it would be just a partial explanation. The challenge was to describe photons, for example. There is a big difference between the way de Broglie describes them and the way Bohm does it. We (with Bohm) found that treating photons as particles through non-relativistic QM will not work. So we were forced in the case of bosons to go to field theory. It turned out that we could in field theory use similar sort of principles that we use for particle theory.

In field theory, we have a field and we have a wave function of that field; so we have a wave functional. This wave functional is a solution of a Schroedinger-like equation. In some sense the photon is the feature, not of the wave function of the field, but of the field itself. So we are beginning to get two levels here. The discrete manifestation of the electro-magnetic field, the photon, is coming out of the classical field, which is controled or which is guided by a superfield. This superfield satisfies the super-Schroedinger equation giving rise to a super-quantum potential. So the quantum potential controls the field and the photons are actually aspects of the field. So, we have two-level-control of the photons.

M.P.: You want to avoid special role of the observer in the quantum theory. Why? What do you propose instead?
HILEY: The reason why one thinks the observer should not play such a prominent role as some interpretations of QM have given to it, emerges by considering the cosmological problem. We now believe that the Universe came out of some quantum event. If we want to discuss the evolution of that quantum event, then there are certainly no observers around at that time. We cannot use a theory which depends on observations. An observer should not come into the description of quantum processes. QM was introduced to explain the stability of matter. If the quantum theory depends upon the observations then the stability of this table depends on the observer. That is crazy! The earth was here before the humans who observed it! Therefore, why do we have a theory which depends so crucially on the observer?

You asked what do I propose instead. Quantum transitions should be something in which the observer plays no role. There should be no need for the observer. If we use the notion of information, we have novel qualities, which we called active information, passive information or inactive information. Active information is acting on a particle at a particular time; passive information is not accessible to the particle at that moment. But in a two-slit experiment eventually the information that the other slit being open will reach the particle and it will act on the particle producing the corresponding effect. So information becomes active at a later time. Inactive information is information, which because of some irreversible process, gets lost and the particle can never access it again. With the concept of inactive information we can actually explain measurement without introducing the human observer at all. In the presence of a measuring device, the information has become inactive and it can no longer be processed by the particle. That is equivalent to the "collapse of the wave function" in the conventional approach. Here the wave function has not collapsed; this information just is not accessible to the particle.

M.P.: But who decides which information will be active and which inactive?

HILEY: Nobody decides it. To see what happens we have to look at the equations... Let us look at the "Schroedinger cat paradox". The photon goes into a box, which has a possibility one half to be transmitted and one half not to be. If it is transmitted, it triggers a gun which shoots the cat. When you work out the quantum potential for the case when the gun has fired, you have to work it out at the positions of the gunpowder, the trigger etc. when in the fired position. If you use the same positions for the unfired case, you get zero. The quantum potential objectively does not act, because of the macroscopical movements of the particles involved in the device. Thus the quantum potential turns out to be zero. So, nobody decides it. It is zero and it is in that sense that it becomes inactive. So, no human intervention acquired at all.

There is a possibility of retrieving all this by reversing all the positions of all the particles involved, but if you do that, you need another device to return them all. Because of the second law of thermodynamics, the entropy is increased, so you cannot reverse everything. If you have irreversible processes, the information becomes totally inactive forever.

M.P.: There are various answers to the question of the "collapse of the wave-function". Would you agree that this is a question of the level of description: globally or holistically there is no "collapse", locally or "individually" (after breaking the quantum whole into separate parts - observer and observed, for example) there is a "collapse"?
HILEY: I think I have essentially explained that before. There is not a collapse, because the information is still there, but it is inaccessible to the particle. So, if you have a group of particles and you make a measurement on several of them, then the measurement process breaks the correlation implicit in the wave function, so that the information of these particles cannot be communicated to the rest of particles. The information becomes inactive, and this breaks the system up into two separate parts.

M.P.: It seems that two descriptions on two levels are proposed. In the first, the physical system is described by the Schroedinger equation, and it is then "collapsed" by mind. This "collapse" is not describable by the Schroedinger equation. On the global level, the physical system plus measurement plus mind or cognition are described by the Schroedinger equation, and here no discontinuous "collapse" is needed. Can these two levels coexist?
HILEY: This comes out by looking at the von Neumann and Wigner approach of QM. By bringing in the collapse you are then assuming that the wave function is the most complete description of the state of the system. Von Neumann argument was that first you can apply Schroedinger equation to the system, then you apply QM to the measuring instrument plus the system, then to the eye plus measuring instrument plus system, then to the optic nerve etc., and so you can take it further and further back into the mind. Then he has to admit that finally there is a state that the subject perceives. So in a sense this is a kind of dualistic approach. That is what happens in the mind, whatever it is, happens outside of physics. In this approach, von Neumann and Wigner would say, you cannot analyze it further, you have to make a cut. You cannot analyze the mind. It is something totally beyond our scientific experience. Well, now this is changing very much. People are trying to understand the mind and consciousness. Therefore people are not satisfied with the present state of the QM, because they think that the mind has to be a part of quantum equations as well... I do not think that QM is consistent at this level.

M.P.: Could we say that "all parts of the Universe are collapsing the wave-function of all the other parts"? (We can use the word "collapse" in your sense.)
HILEY: I agree with you that there is a problem when you start with quantum cosmology and everything is connected with everything else. You have to explain how the classical world arises. If you want to explain this, you have to consider sub-totalities, sub-wholes. The processes in these sub-totalities are responsible for the "collapse of the wave function". So/P> in that case, every part of the Universe is, in a sense, collapsing the wave function of everything else. In our book "Undivided Universe" we tried to show that it is possible for a classical world to emerge from the quantum whole, but the details still concern me.

M.P.: Would you compare the "collapse of the wave-function" and reconstruction of a three-dimensional image from a hologram?
HILEY: In what sense do you mean?

M.P.: I mean that the "collapse of the wave function" is analogical to the recall of an image from the hologram. While reconstructing the image from a hologram we send the reference beam once again through the hologram and then we get this particular image from it. In both cases there is some sort of transition from the implicate to the explicate order - from many possible states we get one out.

HILEY: Well, you are really asking a much more general question, which is how does the explicate order arise from the implicate order. I do not think I have a satisfactory answer at this stage. There are many different explicate orders, so how do we decide which have to be made manifest at a given time. This seems to require another process, a process of explication. This ties ultimately with the question, how does the classical world emerge. Because, when the classical world starts to emerge, you can use it to explicate different features of the holomovement.

M.P.: Penrose says that gravity "collapses" the wave-function. Wigner and von Neumann said that consciousness "collapses" the wave-function. How would you define supergravity, supersymmetry, consciousness, and what relation or distinction is there between these notions, including vacuum or better holomovement?
HILEY: Oh, this is really a big question, for which we could spend hours discussing. I will give some indication. I have already explained the position of Wigner and von Neumann. Let us have a look at the Penrose position. Penrose has a very interesting idea that exploits a very peculiar feature in general relativity. In general relativity energy cannot be localised. He feels that this nonlocal feature in general relativity is related to quantum non-locality. Therefore he is suggesting that it is gravity which is responsible for the collapse. And if this is the case, then that would be great, because it would provide an objective way of looking at the collapse. But this approach assumes that the wave function is the most complete description of the state of the system. This is an assumption I have questioned.

Supersymmetry is a way to combine fermionic and bosonic structures. Here you could transform fermions into bosons and bosons into fermions. That has, to my knowledge, not been very successful, because it predicts many different particles, none of which have been seen. Supergravity comes out of that, because for the first time there seems to be gravitons appearing in some representations of these supersymmetric groups. Again, that is a large extrapolation and I am not sure whether this is a serious proposal at this stage, although it is very interesting.

How consciousness is related to all this is an extremely difficult question. Certainly consciousness has been introduced by Wigner, but then there is no explanation of consciousness here, because he is using consciousness to explain the "collapse of the wave function". In other words, Wigner feels QM needs consciousness. On the other hand Penrose feels that consciousness needs QM, because he feels that the unity of consciousness can be captured by either this holistic view of nature or the fact that there is a coexistence of all the many branches of the wave function. If one can get gravity to "collapse" one branch, then somehow these things are related to consciousness. He says, you cannot make an artificial intelligence model of consciousness and that something else is involved. He uses the idea of non-computability. He feels, that the collapse is the place where you computability stops. When you can have consciousness and collapse tied together, then you will have something that is not computable and therefore something that goes beyond strong artificial intelligence. But he did not give a clear explanation to me, when I spoke to him. He did not explain how gravity collapses the wave function. His book "Shadows of the Mind" goes more deeply into these questions.

M.P.: He actually says that there is a critical amount of neurons which causes a sort of phase transition similar to "collapse of the wave function".

HILEY: Yes, you need enough energy for creation of a graviton...

M.P.: Why is the "collapse of the wave-function" so mysterious? Can we really avoid it, also conceptually? If we would say that the wave-function "collapses" to one eigenstate and so realizes it explicately, but simultaneously all the other eigenstates are still present implicately (and also potentially), would that be right?
HILEY: You can certainly put it that way. But, once again, there are several different levels. If you take the ontological interpretation, there is no problem with the "collapse of the wave function". The reason why one particular branch remains active, but all the others become passive, is contingent upon the initial conditions. What we can not do in the ontological interpretation, is to control the initial conditions precisely. So, depending upon what initial conditions you have got, you can know, for example, that the "Schroedinger cat" is definitely dead or alive. It is the contingency of initial conditions in the ontological interpretation that is uncontrolable and unpredictable.

M.P.: Would you now please describe your notion of prespace and how you try to abstract space-time and matter from the basic underlying holomovement?
HILEY: If you succeed in quantizing the gravitational field, it will fluctuate in the same way that the quantized electro-magnetic field has fluctuations in it. If we assume that general relativity is the way to discuss gravity, then we know that it is the metric tensor that is potential for the gravitational field. The metric tensor tells us about measure properties of space. So, if the gravitational field is fluctuating, then the metric tensor is fluctuating, which means that measure properties of space are fluctuating and that space-time is fluctuating. What does fluctuating space-time mean? One way is to put a lot of different space-times in a linear superposition, but this is confusing the issue... This is actually a question of categories. Here you still maintain the Cartesian categories. Our suggestion is that when we start with the PROCESS (we should definitely not start with the space-time), then space-time will emerge from it as a kind of explicate order. Prespace is that aspect of the holomovement, from which we can abstract space-time in the form of some explicate order.

M.P.: What is holomovement? Is it "nothing" and at he same time "everything"? "Nothing", when we are not explicitly interacting with it; "everything", when we break its symmetry by interacting with it?
HILEY: That is one way of putting it. Our idea is that "nothing" means "no thing". This ties with the vacuum. We find it very difficult to understand different vacuum states. Recall that when Maxwell was talking about the vacuum, he defined it as that which is left when we take everything that we know about out of it. So it is not really "nothingness". If there are features, which you cannot take out of it (this means that there are no things there), that does not mean that there is no process there. A thing or particle is only a semi-autonomous quasi-stable feature; it has a finite life-time; it is not an entity in itself. If it does not have a finite life-time, we would never see it. But that does not mean that it is not there. The processes, the movements are so rapid in the vacuum, that you have to state that there is no THING there, but there is plenty of energy and activity which is formless. When you are making measurements or interacting with it, you are breaking the symmetry. And making a thing out of it.

M.P.: Are there different kinds of vacuum or holomovement?
HILEY: Yes, there are inequivalent vacuum states. Bogoljubov in Russia made such transformations which are changes from one vacuum state to another and he was able to use it to explain phenomena of superfluidity. The holomovement contains all these different vacuua.

M.P.: What is the role of mind and consciousness in your interpretation of QM?
HILEY: If you take the Bohm ontological interpretation, then it possible to bring in mind, but not directly as for example in the von Neumann-Wigner approach. We do not display the quantum phenomena directly, rather we always display their effects in classical matter. We say that some parts of matter are manifest and the quantum features are subtler and these subtle features are reflected in this manifest order. When we go to the idea of the brain function and thought, the best way to explain this is by considering what happens when we see a shadow in the dark. Immediately there is a chemical response - adrenalyne flows, blood flows faster, electrochemical processes take place, we become frightened and we start to sweat. If this shadow is a friend then all that subsides. So, thought has a chemical side, but also a subtle side. If you like, you can extend this idea to all physical phenomena and say that every process in nature has a manifest side and a subtle side. Mind-like properties are always exhibited in the subtle side. In QM at the lower level we have the quantum processes on the subtle side; they have "mind-like features". These features become more and more magnified as we go through to the matter in the brain. So, in the brain we have a chemical side, which is the manifest side, and the subtle side - thought. It still appears to be dualism with two sides - the manifest side and the subtle side, but Bohm's idea is that if you look at the manifest side, you will see some subtle features in there and some manifest features. If you look at the subtle side, you will see some subtler features, so you can regard those features, which are not so subtle, as manifest ones. There is a whole hierarchy...

Whenever you make a cut, there is always a manifest pole and always a subtle pole. There is never a duality; there are always only two sides and they form a unity, where mind and matter actually merge and become indivisible - although at the higher level you can distinguish between manifest and subtle side. But this whole process is mind, and activity is regarded as what constitutes consciousness. We are living in a Universe, where subdivisions are appearances, not essences.

M.P.: Now, may I ask you directly what mind is, from your point of view? Which is the underlying medium of mind?

HILEY: Mind is not an entity in itself. Mind is a relationship between what can be made manifest at any stage and the subtle features within this manifest order...

M.P.: What is the nature of these subtle features which are mind-like?

HILEY: They are features which work on information. For example, when you are walking and shadow appears, this has a role of an active information - a warning, which goes to the brain and chemical processes get to work. Then further information comes in so that the status of the original information is changed. It may become inactive. So there is a continuous change of information from active to passive to inactive. It is the process that shows a mind-like quality. Then mind is able to process this information. How does it process it? Through neural networks etc.? This is something that people like yourself are trying to investigate.

M.P.: The question remains whether these processes are going on at a neural level or a quantum level or both levels?

HILEY: It is the principle of a quantum process that applies, it is not quantum mechanics per se. You do not apply Schroedinger equation at every level. Rather you say that at every level there is a mechanical feature which is governed by classical processes, and there is this subtle feature, which is governed by indivisibility. If you like, a type of quantum potential, but it is not necessary the quantum potential that arises only from Schroedinger equation. It may arise from much more subtle processes. But the point is to look within these processes and ask whether wholeness appears. We have not translated that into the detailed relations with processes in the brain yet. We have seen how these features arise in QM, now we have to see how they arise in the brain.

M.P.: I research analogies between associative neural networks and the quantum theory. I see that there are important similarities. Do you think that these two levels are in some sort of fractal relationship?
HILEY: Yes, this is what David Bohm and I were discussing before he died. He introduced (in the book with David Peat) a new notion of generative order. The implicate-explicate order by itself is not sufficient. Take the example of unfolding process illustrated in the ink-drop experiment, used to describe the implicate order. There you put in a structure and then show that it is revealed at a later time. We really need some sort of a deeper order, in which there is a possibility to create new structures and new orders. Evolution, for example, is not just by chance; there is some creativity going on in this holomovement. Therefore Bohm needs the generative order which he argues has some features in common with fractals as the self-similarity. But I think we have to go even deeper than that. There are two types of movements - a linear one which was the unfolding of the ink-dots, and also a deeper movement which we have not yet fully grasped, which is changing that overall movement and creating new information and new form. I do not know how you do that in terms of neural nets. I have not seen anybody who would put it in the form of a generative order. With generative order we go beyond QM. We are here talking about the form in which we can carry the content. This new order takes its cues from QM, but it does not use the equations of QM. We have to find the appropriate equations.

M.P.: Could it be plausible to identify, for the sake of modelling only, the "hidden variables" or "beables" with formal neurons in a neural network model - not real neurons as some rigid biological cells, but as some abstract mathematical points)?
HILEY: That is certainly what I am trying to investigate - how to mathematize a process. There are already clues using combinatorial topology where you can analyze a structure process in terms of simplexes etc. John Shawe-Taylor said that the structure that I have been talking about, was very similar to neural networks. I would like to explore this in more detail, present it in a mathematical form to people working in neural network theory and then to interact with them to see whether one can actually combine two different sets of ideas.

M.P.: How would you react to a hypothesis that a SPECIFIC conscious interaction, which uses KNOWLEDGE about the quantum system, is needed for a "local collapse" of the wave-function. Namely, in a hologram (and neural network also) the system reconstructs ("collapses into") an eigenstate (a pattern) if one triggers such reconstruction by presenting only a PART of the pattern. So by knowing the part one can trigger a self-organizing process of the system which results in reconstructing the WHOLE eigenstate or pattern. Without knowing the part only a random interaction would be possible and there is a very low probability that such a random interaction would include the "partial information" needed for the "collapse". Knowledge raises the probability for such an event enormously. What is your response to that?
HILEY: One of the aspects, that is missing from a quantum system, is that idea of actualization. The reason for this is that QM insists on unitary transformations. They are nothing more than the re-description. Nothing new comes out of that...

Prigogine has also been working on this, and our two sets of theories seem to have a lot of similarities. He has been working on the question of time, on the question of irreversibility. In the implicate order, which has irreversibility in it, you have the possibility of time coming out. So you have the possibility of directedness, of coming to an attractor, of determining the evolution of the system. This has to be added to QM in order to bring it closer to what you are doing in neural networks where you have attractor-basins etc. That is missing in QM, or it does not seem to be necessary in QM. Prigogine claims that this might also solve the collapse problem when you are looking at quantum theory in terms of psi being the most complete description of state of the system. I am not sure he has got it right; there are some great difficulties, but it is very interesting. One has to add something to the quantum theory to get these energy troughs which give stability and give pattern recognition in neural network theory. The reconstructing process is not necessarily a quantum-mechanical phenomenon, because you can reconstruct the holograms simply because there are already relations implicit - all the local relations, all the spatial and all the neighbourhood relations are there. The point is finding an algorithm to fill in the missing features of the relationship. That comes out of the algebras of process (one of them is Fourier analysis). I am not sure if QM will help or hinder the understanding of these problems.

I am not sure whether this answers your question. What do you mean by random interaction?

M.P.: If we do not have the knowledge about the part of the eigenstate (pattern), then collapse or, analogically, pattern reconstruction will not occur. A random interaction will not cause it. We need a very specific interaction which includes information.

HILEY: Yes, it is quite easy to see why if you have knowledge it helps, because you then pick out those particular relationships which fit. Where does this knowledge come from? From the memory traces. You see, you could do this purely mechanically. You could have a whole data base. Your eigenvectors label the memory store. If you have a certain eigenvector, then that goes to a certain whole - where you have the whole information and previous experiences. I do not feel that there is anything creative here; it is purely mechanical unless I missed the point of your question.

I would not call that trigger of the collapse "knowledge", I would call it "memory knowledge". Knowledge is knowing about something. You are looking in the book and it is all written there; it is not dynamic; it is not understanding...

M.P.: Of course, for knowledge we use memory...

HILEY: If you are talking about judgement, then that is something else again. If you have something to tell you which eigenvector to use, then you have something that is going beyond the mechanical...

M.P.: Yes. I mean knowledge as something that is determining the initial conditions of that process of the pattern reconstruction.

HILEY: Making the choice? To choose the eigenvector which you are going to use.

M.P.: Yes... Well, this is more a question of cognitive level.

HILEY: I do not think that QM per se, and general forms of Bohm's suggestions about consciousness, have anything important to say about that at this stage.

The question is: is mind purely mechanical? If it is, then you can use the principles of classical mechanics.

M.P.: No, I do not think so (at least not for consciousness).

HILEY: OK, so mind is not mechanical, it is holistic. Therefore there has to be some interplay between the manifest aspect and the subtle aspect. What that is in the case of word "knowledge", which you are using, is not at all clear at the moment.

M.P.: The question is, to which extent some classical complex systems are sufficient, and on what level we need consciousness and QM to take part in mental processes.

HILEY: That is the very deep question which we have to answer. You are putting in different words, what I have said earlier, that you have to find out what manifest aspects display the subtle aspects of mind-like qualities which make the choice. It is not obvious whether are there some neurotransmiters responsible for this, or is it the dendritic field, or is it some superfield, etc. Can the mind influence the quantum potential? We do not know the answer at the moment.

M.P.: I think that neural network theory also needs such notions like implicate and explicate order.

HILEY: I agree. The question is, how to translate these general ideas that I have been talking about into particular situations where we are dealing with networks etc.

M.P.: At the end a special question: What is the role of transcendental meditational and mystical experiences in the context of the whole interview? Professor Bohm was thinking about that also, wasn't he? And you personally also?
HILEY: I do not know quite what you mean by transcendental meditation. Bohm was not a man who would try to transcend..., but he certainly felt that it was a spiritual side to man. I would not call him a religious man, but he was very sensitive, always seeking harmony, understanding, coherence. In some sense this is a kind of spirituality. He was very much concerned with how to handle wholeness, how can we talk about it and begin to analyze it and to use it; how can we be creative. Then he would begin to develop ideas which have certain resonances with the Eastern traditions, meditation, mystical experiences. I do not think he would call them mystical experiences; he would talk about quietness of the mind which would allow the implicate order of the mind to throw up new explicate orders, or allow generative orders to be creative... He was trying to do that in the mind. In that sense you could say that it was a mystical experience. But not mystical experience in a sense that a lot of people would use the word.

M.P.: I wanted to ask you whether he was thinking that it is possible to have experiences of this wholeness which he was often talking about, and on what level is this wholeness, which can be experienced in the mind, represented?

HILEY: He certainly felt that thought directly perceives the implicate order. He told me that in many occasions. He never claimed that he ever had mystical experiences; he was conscious of that, because he was always complaining about the noise of thought. I have to emphasize that David Bohm was a very private man. It was very difficult for me to get into this kind of discussion with him. By trying to abstract from our discussions we had together, I know that trying to achieve a mystical experience was not on the agenda. He was rather trying to understand the implicate order, but because the implicate order required to go beyond thought even, then in that sense it was a kind of mystical experience.

M.P.: That answers my question... To conclude, are there still some topics which have not yet been represented in this interview, and do we have to add or to emphasize anything?
HILEY: We are not presenting these ideas as firm, well established theories. They are rather proposals at a very primitive stage of development. The reason, why we distinguish implicate and explicate orders, is that so often, either in the mind and in QM, one can only display partial aspect of reality. We are involved, we participate in nature, and this necessarily means that we cannot get a view of nature which is out-there, "the third eye view", and get an intellectual view of the whole of reality.

Suppose, in QM, a position is emerging from a process. One can explicate position, but we cannot say anything about momentum, or one can explicate the momentum without being able to say anything about the position. In that sense the uncertainty principle has nothing to do with observation, but is something ontological. We are very familiar with the kind of things that go on in the brain, because we can create certain thought patterns and we can hold them in our mind, but then we cannot hold another one at the same time. Many thought patterns are mutually exclusive. You explicate one type of thought pattern, or you explicate another, but not everything together, because the "eye" that is looking at the mind is a part of the mind.

The notion of implicate order is proposed for people to experiment with it. It is not presented as final form, so it needs a lot of exploration and debate.