Quantum Physics and Causality

A Transcript from The Reasoning Show podcasts.

Copyright June 2007 David Quinn

Guest:    Dr. Richard Healey
Hosts:    Kevin Solway, David Quinn


Kevin Solway:    Welcome once again to The Reasoning Show, discussions of pure reasoning aimed at the very heart of matters.   Today we're talking to Richard Healey, who's currently a professor of philosophy at the University of Arizona.   For a long time, he had a special interest in fundamental physics, which has led him to studies in physics, theoretical physics, and philosophy. His research interests focus on what physical theories mean, with regard to the nature of space, time and causation.   He's traveled widely, giving talks about these matters, and has published a book called "The Philosophy of Quantum Mechanics".    I believe there's another one in the pipeline, appearing later this year, called, "Gauging What's Real".   Also helping me with the program today is regular host, and long-time philosopher of the Infinite, David Quinn.   Are you there, David?

David:   Sure am.

Kevin:   Now, the subject we're talking about today is a notoriously difficult one.   So, Richard, I think it's wise if we begin by defining a few terms.    There's a lot of confusion, not only in members of the public, about the difference between physics, theoretical physics, metaphysics, and philosophy.    It's a common experience that we find physicists, or theoretical physicists, dabbling, often at their peril, in philosophy.   So before we go any further, can you tease out for us what you consider to be the differences between those different areas?

Richard:   I can try.   I'll start by saying I don't think there's any sharp principle division between science in general and physics in particular, and philosophy.   I think that theoretical physics shades over into issues that philosophers have always been interested in.   And indeed, there's a term "Natural Philosophy" which in the old days used to mean physics.   And I think that's a useful term to keep in mind here, as a discipline which bridges the gap between physics and philosophy.   But it is true that philosophy is concerned with things quite other than the study of nature.    It's concerned with ethical problems, and with questions related to the meaning of life, on which physical theories bear only at most tangentially.   So philosophy is a broader discipline, and physics tends to be fairly narrowly focused on specific models and theories and experimental verificational tests of those theories.   But there is this bridge in-between, which is what I'm particularly interested in.

Kevin:   Ok.   So on the one hand you have the "shut up and calculate" practical physicists, if you like, who are basically concerned with getting results, and applying the formulas to get useful results.   On the other hand you've got people who are interpreting the theories, and then we come to questions like causation and the nature of existence.   So there's a bit of a divide there, isn't there?

Richard:   There is, but for someone who's interested in questions about causation and the nature of existence, the first order of business is to try to understand the theories that they've come up with.   How one interprets them might lead to radically different conclusions, about their implications or lack of implications for issues concerning causation and the nature of existence.   That's what the philosopher of physics does, that's what I would describe myself as being, in terms of my professional research interests.   The philosophy of physics is continuous with theoretical physics, but tries to show what physics is telling us, so that other philosophers can understand how to draw out the broader implications.

Kevin:   One of the main interests of David and myself is the subject of causation, and I understand that's also an interest of yours.   What would you describe as the major paradox, if you like, that we're finding in physics at the moment, and what is your personal angle on the solution of it?

Richard:   "Paradox".   I'm not sure that I could say that I would locate any particular paradox relating to causation, in contemporary physics.   But I would say that contemporary physics may turn out to have profound implications for our notions of causation.   I hope there wouldn't be any paradoxes involved.   A number of things that do come up in this context are whether or not the causal relation has to relate earlier to later events, if it's a relation between events at all.   Or would it make sense, and possibly be the case in our world, to say that there could be later events which are causes of earlier events.   That's something that comes up in the context of understanding physical theories.

Kevin:   One of the common problems in physics at the moment is the two-particle experiments, or two waves, or whatever you want to call them.   Non-locality I think it's called: you have two particles that seem somehow to be communicating with each other, even though they can't do it because the communication would have to be happening at faster than the speed of light, yet there seems to be some causal relationship between the two events.

Richard:   This is a particularly fascinating question, on which both experimental and theoretical physicists have had quite a lot to say, going way back to a 1935 paper by Einstein and his co-writers.   Philosophers of physics have had quite a lot to say about this too.    I don't think there's any consensus on what one should say about it.   In particular, whether one should conclude that there really are causal relations between the separated events, concerning measurements on pairs of photons in appropriately prepared states or pairs of other particles, like spins of other particles prepared in appropriate states.   There are some people who take "non-locality" to mean simply the presence of a causal relation.   There are others who take the term "non-locality" more broadly, to label a puzzle, rather than a solution to the puzzle, where the solution to the puzzle doesn't involve any causal relation between the separated events.   So there's still no consensus on this.

Kevin:   There's not even consensus on whether the separated events are really separated or not.   It's really an illusion that they're separated.

Richard:   One solution that's been proposed is simply that there are not two separate events at all: there's a single event.    Therefore, talk of causal relationships between distinct events is inappropriate in this context.

Kevin:   Have you ever studied much of Buddhist philosophy at all?   Or different religions?

Richard:   No, I haven't.   My acquaintance with all religions is very shallow.   Some of the things I've heard emerging from Buddhism, I've felt somewhat sympathetic towards, but not sufficiently interested in to pursue further.

Kevin:   There's a lot of relevant material, I think, from Buddhism, where they're not talking about quantum events or electrons, but the whole philosophy of causality is dealt with quite extensively.   David, you've got a question lined up?

David:   I'd like to examine exactly what we mean by "causality".   What you were saying, Richard, about non-causality, the idea of events appearing without any cause whatsoever, is that an issue for you in regards to quantum physics, or not?

Richard:   I'd have to say something irritating: it depends what you mean by "causes".   The prevailing view of quantum physics is that there are events which occur without any prior determining cause.   Now, whether there can be a prior cause which has not determined them, but merely assigns them a certain probability of occurring - and once in a while they show up and sometimes they don't - that's a different issue.   So if we mean a cause is something that is a prior determining cause, then I think that it's not at all clear that contemporary theories of physics are open.   On the other hand, all theories in physics are provisional, and despite our great confidence in our current theories, who knows what science will look like if science is still a practising enterprise 500 years from now?

David:   That's one of the interesting things about the Copenhagen interpretation of quantum physics, which is the dominant, or most popular, interpretation, from what I can gather.   The Copenhagen interpretation has, as one of its assumptions, that it is a complete theory, that there's nothing underneath the quantum realm.

Richard:   What exactly that claim means is a little hard to disentangle, but your way of putting it is a common one.

David:   Is it a correct one?

Richard:   Depends who you ask.   I don't actually think that the Copenhagen interpretation is a sufficiently unified doctrine; that everyone who claims adherence to it would agree with everyone else who claims adherence to it.   In particular, Niels Bohr's views, and he gave it the name "Copenhagen interpretation" because of his institute, are rather more interesting, subtle, and hard to fathom, than those of a lot of other people who would say that they support the Copenhagen interpretation without really understanding what Bohr meant by it.

David:   I understand that.   One of the things that strikes me as intriguing about the whole issue is this choice between ditching the idea that quantum theory is an incomplete theory, that there is more to be discovered, more theories, and so forth, and ditching the idea of determinism.   I find it quite incredible that a group of physicists would ditch the idea of determinism, which is a sound principle that they affirm in their everyday lives, and has been affirmed throughout the history of science.   They've ditched that premise in favour of holding onto what I'd call an illusion, or a pipe-dream, that quantum theory is a complete theory.

Richard:   I think, at some point in our discussion, it would be useful to introduce the views of David Bohm, who I think shared the intuition you just expressed.   Before we do that, I think it would also be useful to reflect upon the fact that, at least in my view, it's not clear at all that the principle of determinism has such a sound basis in everyday experience.   I take it that determinism is an empirical claim, which may or may not hold.   It's a very difficult claim to establish one way or the other, because it's one of those deep claims that is very theory-dependent, and as theories change what we think about whether that claim is true will be likely to change also.   I do take it to be an empirical claim.   I don't take it to be a necessary truth, or a claim that's required for the possibility of scientific investigation, or anything like that.   In my view, it may be true, and it may not be true.   It's hard to find out which, and it would be a mistake to rely on our latest theories as final.   But, it's still an empirical claim.

David:   I'd actually disagree.   I think the truth of cause and effect, the truth that things necessarily come from other things, is a logical claim.   There's really nothing that quantum physics, or any branch of science, can provide as evidence for or against.

Richard:   I think we need to discuss that, because I don't agree with you there.   But before pursuing that disagreement, I'll say what Bohm himself said about this.   I looked this up, because I knew you were interested in this topic.   He wrote a book in 1957 called "Causality and Chance in Modern Physics".   In that book, he distinguishes the principle that:

Nothing simply surges up out of nothing, without having antecedents that existed before.

He distinguishes that, from what he calls "causality".   He claims that the principle that everything comes from other things, and gives rise to other things

....is not yet a statement of the existence of causality in nature.   It is even more fundamental, than is causality, for it is at the foundation of the possibility of our understanding nature in a rational way.
That's what he says.   I think you'd resonate to that statement, even though he takes it that that principle is not the principle of causality.

David:   He's basically affirming that things can't pop into existence, without cause.   Is that his bottom line?

Richard:   I think that's right, yes.   But he doesn't take that principle to be the principle of causality.

Kevin:   I'm not really sure what he's saying that it is.   But, it's not an empirical thing.   And, it's not even something that happens in time.

Richard:   Careful there!   He does say it's an empirical thing.   He says it's a principle which summarises the enormous domain of different kinds of experience, and which has never yet been contradicted in any observation or experiment, scientific or otherwise.

Kevin:   It's still a bit vague, isn't it?   To me, experience itself is not really an empirical thing, but a personal thing.   I can have experiences, but I can't demonstrate those experiences to anybody else.   They're more immediate, in a sense.  They're purely logical existences, if you like.   So, there's a kind of causality that is purely logical.

Richard:   I don't understand that.   Can you explain that to me?

Kevin:   Okay.   Let's say we have an object A.   It could be a chair.   Now, there's something else that is necessary for its existence.   And that's something other than itself.   We have a duality.   So, we have a thing A, and a thing that is not-A.

Richard:   What is the "not-A" ?

Kevin:   It could be its environment.   It's something that is not the chair.   It's everything that is not the chair.   So you could say that there's an interdependence between the two, where they cause each other.   Not in time, but where each is dependent upon the other.

Richard:   I'm not sure I'd want to call that a causal relationship.   It's an interesting dependence relationship.   Let me give you an example of something else that looks like that kind of dependence relationship.   Suppose somebody makes a statue out of a lump of clay.   They say, "It's necessary for the existence of that statue, that it be constituted of clay."   There's a necessary connection, they might allege, between the existence of the statue, and the existence of something, without which it could not exist, namely, the lump of clay which constitutes it.   I take it that that's the sort of thing you are talking about, but I would not call that a causal relationship at all but a relation of constitution, whatever that comes to.

David:   If you define "cause" as something that is necessary for something else to exist, then the clay would be a necessary cause of the statue, because without the clay, there would be no statue.

Richard:   How about this:- I don't think you're going to like this one, but tell me why not.....Isn't the statue also necessary for the existence of the statue, so that it is the cause of itself?

David:   That would seem very technical to me, that one.

Richard:   You don't like it, so there has to be another condition than merely "be necessary for the existence of something".

David:   I don't think it means anything.   If we define a cause as something that is necessary for something else to exist, then the statue causing itself doesn't fall into that definition.

Richard:   Because the word "else" got in there.   Good.   I admire it, but it's not going to get you everywhere you need, because you need to explain to me what "necessary" means.

David:   Without the clay, the statue couldn't possibly exist.   It's necessary to its existence.

Richard:   Now "possibility" got stuck in there, and that's as bad as "necessity".   Philosophers typically distinguish different grades of "necessity", and a correlative grade of "possibility".   They talk about logical necessity, metaphysical necessity, physical necessity, and so on.    What kind of necessity did you have in mind?

David:   Absolute necessity.   For example, a car cannot exist without its parts: the engine and its wheels....   If you take all those things away, there would be no car.   So there's a necessary connection there.   And the same with space, time, molecules.....

Richard:   That's not sounding like the kind of necessity that's discussed in the context of causal relations between events.   That's to say, my dropping something and its landing on the floor: someone might say, "It had to land on the floor, given you dropped it and there was nothing in the way.   So, necessarily it landed on the floor."   That's not the kind of necessity you're talking about?

David:   No, there's no certainty there, between linkages of events, but nevertheless you still need a floor for something to hit the floor, so there's a necessary connection there.

Richard:   I'm still not quite sure what concept of "necessity" you're playing with.   But I can see why you'd think that such a grade of necessity is not likely to be challenged by developments in empirical science.

David:   Even empirically, I can't see how any observation or test by science can actually prove or disprove causality.

Richard:   Yes, but you used that word "causality": is that simply the claim that nothing pops into existence without cause?

David:   Yes.

Richard:   Maybe I should go on and explain how Bohm's view differs from this.   Because he calls something causality, but it's different.   He thinks that the principle of causality has to do with relationships between objects, events, conditions, or other things, at a given time, and those at later times, and that that relationship holds if there is a causal law connecting those causal events or whatever.   He takes it that those causal laws are in a weak sense, necessary, in the sense that the consequent event could not be otherwise, given the initial events and the existence of the causal law.   So that's what he talks about when he talks about causality.

David:   I'm not sure what he meant by "causal law".   That's a type of scientific law or something like that?

Richard:   That's what he has in mind.   He has in mind the law of free-fall.   Or any kind of deterministic law, that given initial conditions, only one later state is consistent with that law.

David:   I'd agree with him, but I'd extract or take away the idea of a law.   I think that causality is, if a thing exists, it has a certain nature, and it's from that nature that other things arise from it, combinations of things.   There's no "law" on top of that.   Causality is just a natural function of a thing's nature.

Richard:   When you think of the causal relation, what do you think it relates?   Do you think it relates things or do you think it relates events?

David:   I don't make any distinction between things and events.

Richard:   I think you need to.   Suppose I say, "My mother is necessary for my existence," I think you'd agree that in some sense that's got to be true.   There, what seems important is "my mother" and the event of "my coming into existence", and indeed, not just anything about my mother, but my mother had to be in certain states, and there had to be various events involving my mother.   So that's what the causal relation really relates: those states and events involving my mother, and the event of my being born and continuing to exist afterwards.

David:   I agree with that, but obviously it's not just your mother.   Your mother was only one of countless other things, for instance, oxygen, space, the evolution of the species, etc.   All these things are contributing causes.   And they've all been necessary, because if they were absent then you wouldn't exist.   So, your mother is just one of an infinite number of necessary causes.

Richard:   Are they all necessary, though?   Couldn't I have existed without a few of them?   Given the way I actually came into existence, there were various events that preceded my coming into existence.   Well: they could have been a bit different, and yet I'd still have been me.

David:   If there was no oxygen, for example, you wouldn't have come into existence.   Or, if your mother had been killed while you were in the womb, you wouldn't have come into existence.

Richard:   That's not necessarily true.   If my mother had been killed when she was near to full term, then I would still come into existence.

David:   For sure.

Kevin:   A lot of it comes down to definitions, I think.   If we define a "mother" as "something that we come from", then we all have a mother, because we all have a cause.

Richard:   You're safe on that one, unless you indulge in science-fictional, or fictional, scenarios.

Kevin:   I guess that's where the term "mother nature" came from: that which is other than ourselves.   All we know for sure is that we come from something that is not ourselves.   We call that "mother nature".

Richard:   Perhaps we do, and perhaps most of the things around us in our experience, do, but you still have to convince me that everything necessarily must.

Kevin:   It's only on the logical level that you can prove a thing is dependent on something other than itself.

Richard:   There were a bunch of philosophers in the Vienna Circle who thought that the only sorts of logical connections between distinct things were essentially trivial, that didn't express any deep view about the nature of those things.   I'm not sure I want to agree with them whole-heartedly, but you worry me a bit when you talk about a logical relation.

Kevin:   Those logical relations are called trivial, but it doesn't mean that they're not deep.   I think this is what we're going to find in the quantum realm.   I think a lot of the discussions are going to come down to purely philosophical, logical arguments that will end up appearing to be trivial, but in fact will describe everything.   For example, all the difficulties about whether two particles are communicating with each other or not, will come down to whether we classify them as one object or two.   So in a sense it seems trivial.

Richard:   I can't accept that.   I personally am inclined to argue that there are two distinct events involved here.   But that doesn't settle the question about whether there's communication between them, or whether they're causally related.   I take that to be a separate question, and a very interesting one.   In the book you referred to [Healey's first book], I tried to argue that our notion of causation itself is sufficiently unclear that there's no simple answer to the question about whether these two events are causally related.   Depending on which of the various components of our rather confused concept of causation one wanted to hang onto, the two events would end up being causally connected, directly, or they would not.   There's simply no answer.   No point in pressing further whether they're really causally connected.   That was my view at that time.   I thought I'd throw that in.

Kevin:   What's your view on the role of consciousness in existence?   Do you believe that consciousness is one of the things that creates the existence of other things, or do you think that things have their own inherent existence?

Richard:   I think both.   I think, certainly consciousness creates things, because conscious people create things, and if they weren't conscious, those things would not have been created.   One can think of grand creations, like works of art, literature, scientific theories, or relatively mundane creations like this morning's breakfast.   Without consciousness, those wouldn't have come into being.   Consciousness creates things, in that sense.

Kevin:   I'm thinking more of the actual things themselves.   All things have boundaries.   Now do you believe that those boundaries are created by consciousness?

Richard:   That's a tricky one.

Kevin:    For example, generally speaking we say a tree ends where the bark is, and with the outer layer of cells on the leaf, for example.   But we don't necessarily have to draw the boundaries there, we could draw the boundaries somewhere else.

Richard:    Yes.

Kevin:    It's the same with all things, isn't it.

Richard:    Yes and no – there are better places of drawing the boundaries and worse.   There's no correct way of drawing the boundary to a tree, and indeed if you press hard enough there's no correct way of drawing the boundary to all kinds of objects, like you and me, or an apple, or an automobile.   They don't have well-defined boundaries.   And yet there are very bad decisions as to where to draw the boundaries and quite acceptable ones.   I take this to be a typical case of vagueness: all terms, all the ways we divide things up using our language and thought, are to a certain extent vague, and yet the vagueness is not such as to permit arbitrary delineations of boundaries around objects.   But let me just pursue this a bit further, because I think when you look at what science says about this, it'll get much more interesting; in particular what quantum mechanics says about the existence of boundaries.   Typically, the picture of a supposedly solid object that would emerge from quantum theory would be one which described that object in a rather abstract way, in terms of a wavefunction or, actually, a density matrix; and if you asked, where does the object finish, where is its spatial boundary, there will be no unique answer forthcoming from that quantum mechanical representation of the object.   Indeed, there would be a nonzero probability of finding bits of that object arbitrarily far away from where you think the object is.   Of course those probabilities would be minute, but there would be no way in the theory to draw a well-defined boundary.   So quantum mechanics, it would appear, would permit one to draw boundaries outside of the range of acceptable boundary choices in our ordinary language.   My car might have a boundary which extends way beyond my garage – even when my car is supposedly in my garage.

Kevin:    The boundaries change, don't they, depending on what's practical at the time.   For example, when you're driving along a freeway at 120 km/h, you might want to extend the boundary of your car quite a bit further than if you're only travelling at 10 km/h on your local street.   In your mind, the car extends further.

David:   It depends on how you conceive of the car.   If we conceiving of it in terms of heat, or electromagnetic radiation, then we'd have a different conception of the boundaries of the car.

Richard:    But they wouldn't typically be useful conceptions for your auto mechanic.

David:   No, but if we're thinking of it in terms of a heat object, for whatever purpose, then maybe we would.

Kevin:    I think these are the same problems that we're finding on the quantum level: when we use different instruments to measure things – of course we're using different instruments because we have different purposes – then different things appear to us.   Because we have a different purpose.   So to me there's a consistency there.   I mean, it's said a lot that the quantum realm is non-intuitive.   But that doesn't sound right to me, because things are going to change if you have different purposes, and if you measure them in a different way.   That seems altogether intuitive to me.

Richard:    I suppose the way of reconciling the claim with what you just said is that most people don't have purposes, and are not familiar with purposes, that would make it relevant to think of things that way.

Kevin:    That's a very good point, because if you're not fully conscious of what your purpose is, then not very much will be intuitive.   Everything's going to seem mysterious, because you're not going to understand what you're doing.   Interesting point.   Did you have any other special topics, David?

David:   Before we move on, I want to talk about the idea of "trivial": what is a trivial truth, and what is an important truth, or whatever.   I think that depends on, yes, on your purpose, which generates your perspective on things.   For example, if you are an ecologist, and you want to examine what causes trees to grow, or how the biosphere operates, then you'd be thinking in terms of the carbon cycles, soil, and water.   That would be your idea of what an important cause is, but there are other causes to trees, and to the biosphere that are outside your interest, such as, time and space, and gravity, and quantum events and so forth.   From the ecologist's perspective they're trivial to him, because they don't have any direct impact on his work.   So, alarm bells ring whenever I hear the word "trivial", because it reveals the psychology of the person using the term, I think.

Richard:    Let me say what I was meaning by it.    I was referring to the view that logical, and mathematical, truths are alleged to be trivial because they just follow from definitions, they are analytic.   That was the claim that the positivists made.   Such that their truth was in no way dependent on the way the world was, so, the triviality concerned was lack of empirical significance, lack of implications for the world being one way or another, such that had the world turned out differently they wouldn't be true.

David:   Yes, and then by the same token a person who is very logical would regard the provisional theories brought out by science as being trivial, when it comes to understanding what is absolutely true in life.

Richard:    You're getting me intrigued again now, as I don't know the difference between truth and absolute truth.

David:   I would consider something to be absolutely true if it's true in all possible worlds, that there's no possibility of it being falsified under any circumstances.

Kevin:    Something that's true by definition.

Richard:    Whoa, two things went on there.   There's "necessarily true", "true in all possible worlds", and there's "true by definition", which I don't take to be the same as "true in all possible worlds", but possibly stronger than that.   Whether it's the same is something that needs to be settled.   You can't just throw the two terms out and say they're equivalent.

David:   Are you saying that definitional truths can change in different circumstances?

Richard:    No, although we can change our definitions, the truths themselves can't change.

David:   Maintaining our definitions, a definitional truth would have to be true in all possible worlds, like 1+1=2.

Richard:    Right, but there may be truths which are true in all possible worlds, which are not definitional truths.   That's the interesting question.

David:   Do you have any examples of that?

Richard:    No, I don't, that's why.....

Kevin:    That's a difficult question!

Richard:   There's a notion of metaphysical possibility that's current in contemporary philosophy, where a metaphysically necessary truth is one that's true in all possible worlds, but there may be metaphysically necessary truths which are not logical truths.   For example – I don't necessarily agree with this example, but it's given as an example – it's a necessary truth that I come from the particular zygote that I do come from.   Or, it's a necessary truth that gold has atomic number 79.   Neither of those seem to follow straightforwardly from a definition.   In both cases it seems like it was an empirical discovery though nobody's actually examined my particular zygote to make that discovery.   It seems to be an empirical claim, it doesn't follow from a definition, and yet some people have alleged that it's true in all possible worlds, that it's a metaphysically necessary proposition.

David:   I'd consider to be a logical, definitional truth "you came from your own zygote".   It's just true by definition.

Richard:    If you put it that way, "your own zygote", yes.    You might have to put it a bit more circumspectly, you might have to describe the zygote in less loaded terms, and then say "that zygote" is the one from which you came, necessarily.

David:   Now, I'm interested in the role of free will because, from my readings of quantum physics and people - like Paul Davies, spokespeople for the physics community over the years, and John Bell as well - they seem to place importance on the necessity to affirm the reality of human free will.   It seems to be a deciding factor in adopting the Copenhagen interpretation.   Their thinking seems to be that if the universe is completely deterministic, then there's no role for free will, because everything that we think and do is determined by causes.   Is that a role that is played in the physicists' thinking on this issue?

Richard:    I don't think that it plays much of an explicit role, so if it's there it's in the background, as a sort of psychological factor.   I don't know of physicists who would rely on that as a premise in an argument that they themselves would put forward in defense of the Copenhagen view.

David:   I remember reading a quote of John Bell where he said that the quantum realm can be interpreted as, as he puts it, a "superdeterministic" system, which I take to mean hard determinism.   The problem with that is that the role of free will disappears.   So he thought of that as an objection.

Richard:    Can you give me the reference on that?

David:   I'm afraid I don't, I read it in a magazine years ago.

Richard:    I know that he does discuss free will at one point where he's considering various unorthodox ways of escaping from the conclusion that his own theorem shows you can't have local realism.   One of the unorthodox ways of doing that is to appeal to the idea that when you prepare systems so you can perform the relevant measurements on pairs of them, they are already correlated with the measurements that you're going to perform later on.   He takes it that if that were to obtain, then that would involve your lack of freedom to choose an alternative measurement on those particles, and he takes it that that would be in violation of free will.   Therefore, he takes it that that's not an option that he wants to pursue when trying to understand what's going on in those experiments that demonstrate violation of his own inequalities.   That's where he talks about determinism, that I know of.   Interestingly, he also takes it that free will is not so critical here, in the sense that even some supposedly random device – he appeals to the Swiss national lottery – could not be in that situation programmed to make one rather than another random choice.   So that's where I know he talks about free will.   And it's not in defense of Copenhagen.   Bell certainly doesn't want to defend the Copenhagen interpretation, he was one of its most acute questioners.    I won't say "critics", necessarily.

David:   What do you think of this idea, that some philosophers and physicists put forward, that the so-called indeterminism in quantum theory allows scope for there being a free will to take place?   Do you think that's a plausible view?

Richard:    I take a pretty hard line on this one.   I think that whatever problem there is reconciling free will with determinism, it is not made any easier if you replace determinism by quantum indeterminism.   The move from determinism to indeterminism, even if you have reasons to make it in the case of quantum theory, isn't going to help you rescue free will.   It's going to make things just as bad, or just as good, as they were in the first place.

David:   That's exactly right isn't it.   The idea of things randomly popping into existence is not compatible with the idea of free will, in any way, I would have thought.

Richard:    Well, if the things that are randomly popping into existence are small enough and irrelevant enough to the kinds of actions we take ourselves to be responsible for, and that are under our control, it doesn't matter too much.   Arguably, the kinds of indeterminism – if there are instances of indeterminism that crop up in quantum mechanics – would be insignificant at the level of ordinary human actions, the sorts of things we do take to be under our control.   So I actually don't think it makes much difference either way.

David:   Yes.   Kevin, do you have anything to say at this stage?

Kevin:    One thing I wanted to mention was the Templeton Prize.   Now they're offering up many, many millions of dollars for people who can produce some work that seems to make the idea of God more plausible, at least that's what it seems to me.   Quite a number of people, like Paul Davies, has won great many millions of dollars by writing books like "The Mind of God".   Now maybe you're just using the wrong titles for your books, because I notice you don't have the name of God in any of the titles of your books.

Richard:    No, I will not have his name…

Kevin:    Maybe if you used the word God a lot more, you'd get more money.   What's the story there?

Richard:    That's probably true.   The fact that I use the word philosophy in my book "Philosophy of Quantum Mechanics", probably earned me a few extra bucks.   "God" would be going too far.   I see no relevance to God in anything.....

Kevin:    What do you think about the morality of physicists accepting money from that source?

Richard:   That's a tough one.   I don't want to criticise actual potential colleagues.    Paul Davies is just up the road in Tempe at the moment.

Kevin:    I know there are physicists who will actually refuse to take any funding from the Templeton Foundation, on the basis that Templeton apparently was a businessman who made hundreds of millions of dollars, or billions of dollars, and in their view, is using that money to try and undermine the spirit of science, to shore up religion.

Richard:    I don't think he'll succeed.   I don't think that's a threat that scientists have to worry too much about.   There are lots of corrupting influences in this world and I don't think of that as being a particularly serious one.   If somebody took the money and did something really good with it, then more power to them.

Kevin:    Do you have any views about Christianity and religion?   Are you an avid atheist?

Richard:    Not avid.   I am an atheist, but I'm not avid.   I'm sympathetic to a lot of the good things that can come out of religion; I just am unable to believe what it's necessary to believe in order to get those good consequences.   I think that the belief is not within my power, and I think that's a good thing.

Kevin:   I'm not so sure that good things can come out of false beliefs, that's the only problem.   Some people cite things like, there's a lot of wonderful music that comes from religion, and there's some nice-looking churches and so on, but when you actually consider where those churches and music come from, somehow a lot of their beauty wanes.

Richard:    There's certainly a downside to religion.   Especially the way the world is going these days, it seems to be becoming more and more prominent, as compared to the upside.

Kevin:    It's a difficult subject, it's not sort of something we can talk about for hour upon hour.   Unless there's anything else you want to talk about, David?

David:   We could talk about the Big Bang, whether the Big Bang popped out into existence out of nothing, whether it had previous causes itself.    I know it's a divided issue within the scientific community.   What's your view on that kind of thing?

Richard:    That's a really interesting issue.   We don't really understand what's going on in the very early universe well enough to have a theory that we can trust.   But what we can do is to extrapolate back as far as we can with the theories we have, while well-aware that those theories can't be relied upon in those extreme conditions.   For example, if you just simply extrapolate back with classical general relativity, then there are models of that theory, and indeed models that we have reason to take very seriously based on our knowledge of our universe, which do have initial singularities.   An initial singularity in this context is - I was going to say it's a point at which time began, but that's actually false.   If you trace back along a time-like curve, closer and closer to the supposed Big Bang, at some point the curve simply can't be continued any further, but that doesn't mean to say it has a last point necessarily.   It might be like the numbers.   If you trace back from one, you can get closer and closer to zero, but there is no point just above zero which is the last point you get to.   So within that model, it seems like one can certainly make sense of the idea that the universe has not always existed, but there was no point in time at which it came into existence, and there certainly wasn't any time before there was a universe.

David:   Unless this singularity was produced by a previous universe.

Richard:    When you call it a previous universe, what does that mean?   If it's a singularity, there's no temporal connection between our universe through the singularity and the supposedly earlier universe, so to say that there was a previous universe is literally nonsense in that case.

David:   Isn't there a kind of school of thinking that the universe oscillates from Big Bangs to Big Crunches?

Richard:    Sure!   My point was that if you take that theory absolutely seriously, then the implication is that there was no earlier universe, there was no oscillation, because it would have to be connected temporally to our present universe and it couldn't be.   But this is all within the realm of a particular theory which we have good reason not to trust in such extreme conditions.   So we're looking for a better theory, and physicists have come up with various suggestions, but I take them all to be pretty speculative, frankly.   What's interesting is that you can actually make sense of some of these speculations and, if they turn out to be correct, they do have profound implications for what we say about time, and the universe coming into existence.   It may well be, for example, that a successor theory to our current theories of space and time would be a theory within which the concepts of space and time themselves don't even figure at a fundamental level, so that they emerge from such a fundamental theory in a certain realm, as it were.   If that were true, then the question "Did the universe come into existence or was there something before it?" would be literally meaningless in the context of such a theory.   We don't have such a theory which we have good reason to believe, but it's interesting when considering the question, what we would say if we did.

David:   The problem is of course that it merges more and more into the realm of theology and speculation, because there's no means of conducting the scientific experiments to test some of these theories.

Richard:    It's increasingly difficult, that's for sure, but I don't think one should totally give up hope.   One of the challenges is to come up with ways of testing these theories.   So, maybe it'll take us a long time, maybe we'll succeed and maybe we won't, but that's the enterprise of science.

David:   Have you ever noticed a tendency in physicists to be kind of arrogant about their work?

Richard:    Oh yes.

David:   I get the suspicion that they like to think they're the lords of the scientific community, and that all the other realms of science are the lesser forms.

Richard:    It's even something that occurs within the physics community.   There are physicists who think that all the action is in elementary particle physics, high-energy physics, and therefore it is "entirely justified" that we should be pouring billions of euros into the Large Hadron Collider in Geneva, on the other hand there are physicists who think that's not really where the interesting physics lies and they should get some of the money because what they do is more important.

David:   They have to sell themselves, don't they.

Richard:    That's right.   You're quite right, there is an arrogance there, and to a certain extent I am sympathetic towards it, because there are some very bright people who have reason to believe that a lot of what they're doing is not adequately understood, and therefore they have some kind of knowledge which is not available to other people, so they are an authority.   On the other hand, it's not clear that they always restrict their pronouncements to the domain within which they really are experts.

David:   Yes, I find that when a lot of physicists begin to philosophise, they seem very nave to me.   Their knowledge that they've gained through physics hasn't really informed their philosophical speculations too much, because their thinking can be quite irrational and undeveloped.

Richard:   Physics in particular is an interesting science because there's a kind of ideology that one encounters frequently: physicists who take it that philosophy is in some way a bad thing.   There was a wonderful quote I heard from Max Tegmark, that physicists really quite like to talk to philosophers, but they never like to be seen coming away from talking to philosophers, it's rather like being seen coming out of a pornographic movie.   You can see the attraction, but you don't want people to know that you're doing that kind of thing.   So philosophy has a bad name in certain circles, in physics:   "That's just philosophy!" you will hear.   That makes it somehow worse, or beneath contempt.    That's unfortunate.   It's not the kind of attitude one gets in other areas of science, quite so often.

David:   I wonder how much it does persuade them to certain courses of action, like for example we had the famous case back in the late 19th century where the physicists at the time believed that they had solved all the fundamental questions, and it was just a matter of dotting the "i"s and crossing the "t"s and whatnot, and then quantum physics and relativity came along, and nowadays I get the same impression that they're doing the same thing…   There's a kind of natural tendency of the physicist to try and wrap the entire universe within their equations and their models.   You get that with their statements that quantum theory is a complete theory, that there's nothing beyond it, or that there's nothing before the Big Bang.   I find it amusing.

Richard:    Let me just say a couple of things about that.   I think that the Copenhagen orthodoxy is crumbling a little, these days.   Even people who want to defend the Copenhagen view tend to do so in ways that would be considered deviant by the original proponents of the view.   And there are plenty of physicists around today who would not want to defend the Copenhagen view; there are radical unorthodoxies which are attracting significant numbers of followers.   I mean Bohmian mechanics attracts quite a large number of followers, more in the community of philosophers than the community of physicists, and mathematicians also take that very seriously.   Also Everettian approaches, popularly known as many-worlds interpretations, have a substantial number of adherents these days.   So we don't really have the same kind of Copenhagen monolithic orthodoxy as at least was supposed to have obtained after Bohr supposedly beat down Einstein's criticisms.   Things are opening up there.   As far as the physics goes, too, I think that things are opening up there.   All kinds of things are emerging from cosmology these days that really don't fit into existing theories of physics at all well.   There's lots of excitement about the nature of dark matter and dark energy, which is making it clear that the physicists haven't said the last word about what our universe is made out of, and would like to be able to say more.   Indeed, the current investigations with the Large Hadron Collider: when it gets going next year, physicists hope that they will unearth unexpected things that would enable them to do new physics.   They're getting rather bored of having the Standard Model around for the last thirty years, without any advances.   So I don't think that you'll find too many physicists these days saying, well, the end of physics is nigh, we've got it all pretty wrapped up.

David:   Do you think the Big Bang model then is going to be superseded at some point?

Richard:    It depends what the Big Bang model involves.   I think there's very good evidence that the conditions in what we call the early universe were very extreme and that we have a well-developed theory of what happened after the first few microseconds leading up to the expansion of the universe over the past 13.7 billion years, or whatever.   That's in pretty good shape.   But if you push it back and back, then inflationary cosmology is not on such solid ground, although it's doing pretty well, and of course if you push it back early enough, then we have no theory to describe what's going on.   So, something is going to remain, that you can call the Big Bang if you like, but things are going to change.   There's lots of open territory for new theories in the very early stages, as we say, of the expansion.   Unfortunately, as you already pointed out, that's an area where it's very difficult to get good experiments to decide whether the theories people come up with are good theories or not.

David:   Yes, I remember 10 or 15 years ago reading about some scientist's complaints about how the Big Bang cosmology has dominated cosmology so much that it's hard for any alternative theory to get a look-in, but I suppose the younger generation's coming through now, making challenges.

Richard:    I'm not sure that's the right way to put it.   They're not making challenges to the fundamentals of what people call the Big Bang model, they're making challenges (if they are challenges, maybe there's nothing to be challenged) about what to say in the extremely early universe.   But let me just throw something else out – to change the subject slightly to what we were talking about earlier.   One rival to the Big Bang model a long time ago was the steady-state theory, and that came to be ruled out pretty definitively by observation, but there was one feature of the steady-state theory that I wanted to draw to your attention, to see what you thought about it.   The steady-state theory postulated that over time the condition of the universe could stay pretty much the same.   How could that be compatible with the expansion of the universe that was observed?   Well, because hydrogen was being created out of nothing, at a very slow rate, everywhere.   And even though the universe was expanding, there was more matter being created to fill the gaps as it were, and therefore the overall state of the universe would be pretty much, on a large scale, unchanging with time.   So, wouldn't that be something popping into existence out of nothing.

David:   It would, yes, that would be unfeasible from my perspective, for sure.   I don't have an opinion for or against the Big Bang, but my intuition is that Nature on a large scale operates fairly similarly to how Nature operates in our normal perspective, and the Big Bang seems like it's a contrivance.   This idea that everything's contained within this explosion, and expansion, and so forth.   It just doesn't seem to ring true to me.

Kevin:    I think there's a problem there too with the definition of "universe".   I grew up thinking that the universe was one thing, one thing only, as the name "universe" would imply: "universe" comes from "uni", which means one.   But then in the last couple of decades you hear people talking about different universes, and that gives me a headache.....

Richard:    The language is getting stretched there, you're right about that for sure.   I think the best way of talking about it is to distinguish between the universe and the multiverse, so the multiverse is what you think of as the universe.

Kevin:    That's exactly right.   So if there is a Big Bang, and if what we see around us are the remnants of this Big Bang, then I think we should come up with another word for it than "universe".   We should probably call it our observable universe, if you like, as opposed to "the universe", which may include an infinite number of "observable universes".

Richard:    I am sympathetic to your proposal.   There's actually a problem with the way you put it, though, because right now, even if there's only one of these things, we have to distinguish between the universe and the observable universe, because according to current cosmological models, there are regions of our universe which are not observable, because nothing from those regions could have reached us even if it were travelling at the speed of light since the Big Bang, so there's no way that we could observe what's going on in those regions, even if it's regions of our universe.   So that's not going to be the right linguistic reform, but I support your proposal for linguistic reform, and I guess the best thing that's on the market now is to talk about the multiverse.   But then maybe you wouldn't like that because that suggests there's more than one universe and you don't want to say that.

Kevin:    No, we don't want to do that.

David:   It's just definitions, it's a semantic argument there isn't it.

Richard:    Important to keep terms straight, otherwise people get confused.

David:   It strikes me as intuitively plausible that what we call the observable universe – everything created by the Big Bang and whatnot, is just one –

Richard:   - That's different, though.   I just said.

David:   Okay, but what we call this cosmos, space-time cosmos, which we tend to think of as being all there is, is really just one tiny little speck in a vast infinity of Reality.   It's just speculative, but it strikes me as being plausible.   Given that, all the theorising by science and physics and this idea of completeness of quantum physics and all this kind of stuff, comes across as being absurd.

Richard:    I'm not sure "absurd" is the right word.   You're putting it in a perspective which is a useful perspective.   One thing that I think is really significant about the advance of scientific knowledge is that it seems to have been accompanied consistently by an advance of scientific ignorance, if you like.   When the world was just a friendly familiar place within Aristotelian cosmology, even though the theories that we had of it weren't very good, at least the world wasn't such a big place, and we didn't have a huge sphere of ignorance.   But today we have to admit that we're enormously ignorant about a lot of what's going on, just in terms of the composition of the universe.   We now know that almost everything in what we think of as our universe is quite different from matter around here; we think most of the matter and energy of our universe is nothing like what we see on the earth, in the solar system, in our galaxy, because most of it's made up of dark matter and dark energy – if dark energy is a form of matter.   So we have massive ignorance here, accompanied by increasing knowledge, and that's kind of the pattern that science has displayed to us.

Kevin:    Well, we'll call it a day for now, so thanks very much for talking to us Richard, and thank you David.

David:   Not a problem.

Kevin:    So till next time, it's goodbye from The Reasoning Show.

 

 


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