101 Dr. Ruth Kastner and the transactional interpretation of quantum mechanics

[00:00:00] Ruth Kastner: Quantum systems really are elements of possibility in a sense that exist outside of the space, time manifold. And so that these interactions are not literally things going forward in time or backward in time, but rather they’re sort of possibilities that are in play.

[00:00:21] Al Scott: The rational view is a weekly series hosted by me, Dr. Allen Scott, providing a rational, evidence-based perspective on important societal issues.

[00:00:38] Soapbox Media: Produced by Soapbox Media (soapboxdigital.media)

[00:00:42] Al Scott: Hello, and welcome to another episode of the rational view. I’m your host, Dr. Al Scott. In this episode, I’m looking forward to exploring more about alternative interpretations of quantum mechanics. In previous episodes, exploring consciousness, I’ve encountered several people who believe that quantum [00:01:00] mechanics is at the root of consciousness.

[00:01:02] The hard problem of consciousness is supposedly explained by quantum mechanics. My current thinking on this is that this just replaces one mystery with another one without really providing an explanation for how consciousness arises and maybe it’s right. Maybe this consciousness is an aspect of the universe, is an aspect of a field or a, a wave function, a preexisting property of some sort, but we’re still stuck with the options of this or some sort of emergent property of a neural network or a processing network. Either way, quantum mechanics is an often misunderstood yet brilliant theory at the basic underlying portion of physics. It tells us that microscopic particles don’t exist at a specific position with a specific momentum. They are however, very accurately represented by something called a wave function, but nobody knows [00:02:00] what this wave function really represents. That it’s been called “the dreams that stuff is made of.” They’re used to calculate very accurately, the distribution of a set of repeated measurements on identical particles. The process of observing or making a measurement, however, is poorly understood. In fact, it causes this wave function to collapse from a universals probability distribution to a single spot in time and space. The process of this collapse is not defined in the theory. There’s a problem with quantum mechanics and this is called the measurement problem, and it’s never been adequately explained. And this is why there are so many different interpretations of quantum mechanics out there.

[00:02:42] For example, you may have heard of the many worlds theorem, this theorem posits that the wave function doesn’t actually collapse; the wave function describes the continuum of all potential universes that could exist. And it says that they all do exist. And the measurement problem doesn’t [00:03:00] collapse the wave function to a point, it merely tells you which of these universes you’re actually in. There are others: the Copenhagen interpretation is the mainstream one where a measurement randomly collapses the wave function based on a probability, which is the, the amplitude of the wave function squared. And there are various mathematical tools which we can use to get these things.

[00:03:24] My current guest is someone who is a leading proponent of another interpretation of quantum mechanics called the transactional interpretation. If you like what you’re hearing, please press like on your podcast app, share it with your friends. I’d love to see you on my Facebook discussion group, the rational view, or come visit my webpage at therationalview.ca

[00:03:48] Dr. Ruth Kastner earned her Masters in Physics and PhD in History and Philosophy of Science from the University of Maryland. She has taught widely and conducted [00:04:00] research in foundations of physics, particularly in interpretations of quantum theory. She was one of three winners of the 2021 alumni research award at the University of Maryland College Park.

[00:04:12] She’s the author of three books, “The Transactional Interpretation of Quantum Theory; the reality of possibility,” “Understanding Our Unseen Reality; solving quantum riddles,” and “Adventures in Quantum Land; exploring our unseen reality.” She’s presented talks and interviews throughout the world. And in video recordings on the interpretational challenges of quantum theory and has a blog@transactionalinterpretation.org.

[00:04:42] She’s also a dedicated yoga practitioner and received her 200 hour yoga Alliance instructor certification in February, 2020, Dr. Kastner, welcome to the rational view.

[00:04:53] Ruth Kastner: Thank you very much. I appreciate the invitation.

[00:04:56] Al Scott: So I’ve been doing a series of interviews [00:05:00] exploring the concept of consciousness, and this is such a broad ranging thought. There’s philosophy, there’s physics, there’s neurobiology. So many different diverse fields of thought focused on what consciousness might be. And I’ve encountered, I’ve encountered several theories that link back to alternate versions of quantum mechanics associating that with consciousness. Now you’re a lead proponent of what’s called the transactional interpretation of quantum mechanics, which is one of these competing interpretations that, that physicists are trying and physicists and philosophers are trying to work out exactly what quantum mechanics means, because you know, a lot of, if you ask a physicist and poke at them, they’ll say, okay, it’s not a complete theory.

[00:05:43] There is, there are problems. There’s the measurement problem, or this wave function collapsing. Could you give us an introduction to the transactional theory and, and maybe walk us through the major concepts of this, of this idea?

[00:05:56] Ruth Kastner: Sure. So I guess I should… you’re interested in [00:06:00] sort of in quantum theory and interpretations, and, and also you’re kind of interested in how does consciousness fit in with all this?

[00:06:07] So, I mean, I should say probably right at the outset that, that the transactional interpretation, really formulation of quantum theory, doesn’t really, it’s, it’s pretty agnostic on consciousness, so it doesn’t have anything specific to say it doesn’t invoke consciousness in, in any, you know, explicit sort of way.

[00:06:27] And, but we, we can still talk about what what might we learn from quantum theory that might have to do with consciousness, and that, that’s an interesting question. But as to the, the transactional interpretation itself, you had mentioned that, that some physicists think that quantum theory, isn’t, isn’t a complete theory. And, and traditionally that description or that characterization of quantum theory is not complete was, was in the context of, of trying to add hidden [00:07:00] variables to it. So you know, trying to kind of say, ‘well, quantum theory seems to have these problems and, and it seems to have this kind of indeterminacy’ and, and the difficulty of explaining how we get measurement outcomes, you know, the measurement problem.

[00:07:16] And so for a long time, a, a lot of the approaches to interpreting quantum theory had to do with, with hidden variables. The idea that, that our quantum systems really do have some kind of hidden property or hidden feature about them, that, that our quantum states just can’t describe or can’t get at. But if we kind of supplement the theory with these hidden variables, then we’ll have some kind of a better understanding of, of our reality. Well, it turns out that that’s fairly hard to do in a way that is fully satisfactory in a way that is fully relativistically you know, meshes with the relativistic forms of quantum theory and so on. So, and it, it [00:08:00] tends to do things like kind of pick out a preferred inertial reference frame, which you’re not really supposed to do and that kind of thing. But the idea that the standard formulation is somehow missing something, it is an aspect of the transactional formulation. And what it really does is the transactional… I call it a formulation because in a technical sense, it’s, it’s more than just an interpretation because it really does feature a kind of physics. It has physical content that isn’t in the standard theory and that is basically a different way that the fields, quantum fields by which I mean basically influences, you know, that where, where a system can interact with another system, those interactions are typically viewed as being mediated by fields and, and the quantum systems themselves are seen as kind of field [00:09:00] excitations that have a certain kind of, you know description in terms of quantum state. And in the transactional picture, the fields behave very differently and they’ve got this non locality. So in terms of the original formulation by John Kramer, who did the, who kind of created this, this original approach back in the 1980s, you have not only the sort of ordinary quantum state that has a kind of forward, directed component to it, but you also have a response that is actually kind of pass directed, which is called an advanced state of the field. And I mean, it gets quite technical and I don’t know how, you know, how much technical detail you wanna go into, but sort of at the, the nutshell version, sort of the the primer version, and we could always, you could always go into more detail, but the primer version is the idea that what’s missing from the standard theory is not [00:10:00] simply something being emitted, which is called the offer or offer wave in T.I., but something actually coming back and responding to that. And when you include that absorber response, then you get measurement and you get a very clear idea of, you know, what is it that’s physically going on when we do a measurement. So that’s kind of the very, you know, brief overview version.

[00:10:25] Al Scott: That’s great. So the terminology is a little bit confusing.

[00:10:28] There there’s an offer wave from a particle that might emit something and another wave that comes backwards in time from something that might receive that energy or that particle, is that correct?

[00:10:41] Ruth Kastner: That’s correct. But what I, you know, I mean the thing that that really gets problematic and, and confusing is the idea of things going backward in time, you know?

[00:10:52] Well, does that mean the future is sending signals back in time and so on? And I don’t view it that way. I think that that in my [00:11:00] work, what I argue is that quantum systems, quantum states are, are really not space-time objects. So this is a bit radical. It kind of requires a kind of a retooling of our conceptual approaches to understanding reality.

[00:11:15] But it’s the idea that these are kind of that quantum systems really are elements of possibility in a sense that exist outside of the space-time manifold. And so that these interactions are not literally things going forward in time or backward in time, but rather there’s sort of possibilities that are in play that have a kind of time symmetric character simply because they aren’t actualized yet. So you can, you, you typically will get what’s called an offer that has different components that reach a bunch of different absorbers that would be eligible, say to maybe receive a photon. The photon that is possibly is being [00:12:00] offered. And so these different absorbers are going to send back a component of what they received and you basically get kind of a competing set of what I call incipient transactions, and only one of these can really be actualized such that the photon goes to one of those responding absorbers, but not to all of them. So that’s corresponds to the collapse that we get in measurement.

[00:12:29] Al Scott: Okay. So this represents the, the collapse of the wave function that it you want from, from standard quantum mechanics, one expects during measurement.

[00:12:38] There’s a collapse from a a set of probabilities, which is represented by the, the square of the amplitude of the wave function, and it collapses into one of these things based on that probability distribution. And, and so from the transactional theory, the collapse occurs when an offer wave goes forward.

[00:12:57] And a what what’s the return wave called?

[00:12:59] Ruth Kastner: It’s [00:13:00] called a confirmation wave.

[00:13:01] Al Scott: Confirmation wave comes back and all of these then will interfere I assume, following the same rules of quantum mechanics?

[00:13:09] Ruth Kastner: They don’t actually interfere. Yeah, this is the interesting thing; what you get, I mean, interference takes place at the level of, of the, of a single offer component or sometimes a single confirmation component, but once you get what, what you get when you get these these responses, they’re actually very almost like columned, they’re targeted so that the the technical expression of it, I mean, it becomes clear when you look at the math, you know, but the technical expression of this is, is that they each have their own separate character, so that each of these, what I call incipient transactions are really just an offer component and it’s absorber response that matches it and they set up a kind of a, what’s described by what’s called a projection operator in quantum [00:14:00] theory. So these are entities that are autonomous in a sense that, so you have a projection operator for each of these incipient transactions. They don’t mutually interfere. They have a kind of an autonomous character and they each have their own weight. That is this probabilistic weight that you get by technically taking the outer product of the offer wave component and the confirmation wave component. So once you get that interaction, that’s called a non unitary interaction. When you get this absorber response going on, you really do get this kind of autonomous set of projection operators, each of which corresponds to an outcome. So it isn’t a case of just kind of an interfering, ordinary little wave function that has interfering components that the interference actually gets broken by this absorber response.

[00:14:53] And if you look at the math, you know, it’s, it’s, it’s got a mathematical representation that, that kind of captures [00:15:00] this what’s called non-unitarity.

[00:15:03] Al Scott: Okay. So there seems to be a lot of machinery to this interpretation. What problems does it solve in, you know, if we were to deposit that this is the proper interpretation of quantum mechanics, how does that improve our understanding of quantum mechanics?

[00:15:19] Ruth Kastner: Well what it does is it actually explains, it gives you the physical process that underlies a lot of expressions that we already use in quantum theory, such as I mean, Von Neumann who is this brilliant mathematician who constructed a mathematical formulation of quantum theory that had all these kinds of processes in it in mathematical form only. So he kind of said, okay, well sometimes it seems like we’ve got a certain kind of evolution that, the technical term is unitary, which means it’s this kind of force based, the action of forces. And then sometimes we have this measurement [00:16:00] transition and he didn’t know, he couldn’t say what causes it, but he said, this is how this is its mathematical character. And he represented that mathematically. So that was a very useful representation that, that seems to when you use it as a recipe it corresponds to what we see, but it, it was very mysterious as to, well, what is it that causes this, what’s called a pure state that I prepare my system in a pure state. And then it somehow transitions into this mixed state, which von Neumann was correct that that is the correct mathematical representation. What I just described with the transactional picture actually gives you this transition from your pure state, your pure unmeasured state to what’s called a mixed state. That is just that set of projection operators with their weights. So it sounds, you know, when you describe it, in words, you know, I’ve got this offer wave and I got that confirmation wave coming back, and it sounds kind of, you know, why, well, that [00:17:00] sounds really, really unwieldy, but in fact, it corresponds perfectly to the mathematics that we already use in the theory. But without the transactional, the physics of the transactional picture, it just becomes some mathematical recipe that you don’t know why it works, and you can never say, well, at what point has the measurement taken place? You know? So that’s why we get the, the Schrödinger’s cat paradox, and we get all these paradoxes. You only get those because you’re not able to say what’s triggering a measurement transition. So with T.I. you can very, you know, quantitatively point out you can, it’s not deterministic. I mean, you can’t say you cannot predict a time, T, I’m gonna have a transactional process. You can’t do that because quantum theory is really fundamentally indeterministic, but you can give a quantitative description that will give you the probability, say that any particular time T [00:18:00] under certain conditions given, you know, what kind of atom I have or whatever, that I’m going to get a me measurement transition.

[00:18:07] So it solves the, it really solves the measurement problem in that respect.

[00:18:12] Al Scott: So this gives a, an objective criterion or an objective explanation of, of how the, the wave function collapses, it projects onto reality effectively onto a, a measurable real world state from its multiple overlapping probabilities.

[00:18:29] So how would this change the Schrodinger’s cat experiment? This is, you know, the Schrodinger’s cat is a very popular and well-known thought experiment about; there’s a cat in a box with a radioactive source and a poison gas vile, and if the radioactive source emits a particle within its half life, then the, the gas is released and the cat is dead. But if you don’t open the box, quantum mechanics says that they’re in a superposition of dead cat and live cat.

[00:18:54] Ruth Kastner: The standard theory does, right. So, so will the, what TI does is it says, [00:19:00] okay, well, the standard formulation is missing some of the physics, and what it’s missing is the idea that you know, we could get into some technical subtleties if we dealt with radioactive decay, it still works out, but we’ll discuss it in terms of, suppose we just had an excited atom that could give off a photon. Okay. So, it has some probability, but this is basically a decay rate. So it has a rate of decay such that, you know, it has a 50% probability within say an hour that it has decayed, but with TI what happens is decays don’t happen, don’t occur unilaterally. So the only reason you get this kind of decay process is because you’ve got an interaction between the emitter, which is the unstable atom, and all the absorbing atoms that are present. In this case, in the Geiger counter or whatever it is that’s going to provide the, the absorption for your photon.

[00:19:56] So instead of kind of just this [00:20:00] superposition that is in this pure state, what you get with the transactional picture is you really get this mixed state that gives you a probability for any time T, that you’re going to get this photon emitted and absorbed. So rather than have a superposition, you’ve actually got a set of projection operators with a very well defined probability and the reason and, so what’s going to happen is that it’s the absorbers in the Geiger counter that are going to trigger a collapse long before any sort of a macroscopic object, like a cat, can become, you know, part of the superposition. So by circumscribing the decay process, the way it does it, it doesn’t let DKS just kind of happen unilaterally. They only happen because there are responses, absorber responses. So when you’re getting these responses, [00:21:00] that’s what’s triggering this transition. It’s a real physical transition that’s missing in the standard picture. So even though it’s indeterministic, I mean, nobody can predict when you’re going to get collapse, but the probability of collapse is overwhelmingly huge that it’s going to occur with respect to these microscopic systems rather than, you know, an entire cat.

[00:21:24] Al Scott: I see. So in this case you typically don’t have macroscopic superpositions in this theory. The way function will automatically, or, it will collapse when the interaction happens and you can’t be in a state where it may have happened, or it may not have happened. It it’s gonna collapse.

[00:21:41] Ruth Kastner: Right. Yeah. And, the key here is that really the probability of a transactional process, which is what triggers measurement and collapse, is overwhelmingly large for any kind of system that approaches macroscopic proportions. So in the theory, you know, I [00:22:00] present this in, I have the latest version of my Cambridge book that just came out this past month, where it’s the second edition of that book, where it does go into some quantitative detail that shows exactly why for more and more complex objects, you know, ma more macroscopic kind of size objects, the more overwhelmingly likely it is that you’re going to get this transactional process within a very short period of time so that you’re not gonna be able to get these kinds of superpositions.

[00:22:28] And it corresponds perfectly to the decoherence that we often hear about. We often hear the word decoherence in the traditional theory, but in that context it’s kind of missing some crucial content. So it becomes a bit hand wavy and a bit circular. But I’ve been showing how we get this real physical decoherence in the transactional picture that really leads to collapse, and as an objective kind of physical process.

[00:22:56] Al Scott: So can you contrast this with the [00:23:00] standard Copenhagen interpretation? Are there any predictions from this that would be measurable or observable that would differentiate this from what people typically think of when they’re, you know, spudding about the Schrödinger’s cat?

[00:23:16] Ruth Kastner: Well, this is an interesting question because at the level of the born probabilities these two formulations are completely equivalent. They’re empirically equivalent in that, and this is actually a theorum that you can, you know, look at at the relativistic level, that the field behavior in this, what’s called the direct action or absorber theory, is actually empirically equivalent to the standard theory at the level of probabilities.

[00:23:42] So, you know, people are often, you know, they’d really like it, if we could say, okay, here’s a test you know, where TI predicts something that would be like an experimental way to discern experimentally between these two. But what I’d like to point out, I guess, is that we do have an anomaly, an [00:24:00] anomalous situation in the standard theory, which is that we experience empirically, measurement results. We get measurement results. And the standard theory is unable to explain that. So at that empirical level that, okay, empirically, we all, you know, we find specific, unique experimental results. We don’t have cats and superpositions and so on. Well, this is what ti predicts.

[00:24:26] This is what the transactional interpretation actually predicts; it predicts that you will get a measurement and a collapse, you know, under these specific conditions. Whereas the standard theory, you know, that is the measurement problem, that it, that the standard theory fails to predict measurement results and even fails to be able to say what measurement is.

[00:24:47] So I’d like to kind of, you know, make that distinction at the level of the probabilities are the same, the probabilities are the same. However, the standard theory just can’t account for our empirical [00:25:00] observations.

[00:25:00] Al Scott: Right. That’s the measurement problem. It just doesn’t say what an observation is and who is an observer. It suffers from this horrible lack of definition as to what an observer is. And there’s been all sorts of speculation, whether it requires intelligence and you’ve got Wheeler and the group, you know, thinking of all sorts of different ideas about, you know, people thinking that you need intelligence is that an observer is an observer, just an interaction?

[00:25:26] So this basically clearly spells out that it’s an absorption of energy that is required, a transfer of energy from one particle another? Do we have a clear definition mathematically of an absorber?

[00:25:38] Ruth Kastner: Yeah. And an absorber is basically a field source that can respond.

[00:25:44] So, I mean, basically what triggers this measurement transition, what precipitates, the measurement is absorber response. And actually that’s a non relativistic statement. At the relativistic level, what you [00:26:00] really have is a kind of a mutual interaction that is non unitary. So there’s a particular kind of emitter absorber interaction. And the basic probability of it is governed by the fine structure constant, which is basically two factors of the charge of, you know, the charge of your electron or object that is the source of the field. So again, it’s indeterministic. But it is a specific non unitary interaction. So, we kind of have two levels in this transactional theory. We have at the level of force, we have what’s called a unitary interaction and that is just a direct connection. So suppose you have, you know, when you have two electrons repelling one another, now that’s not a measurement. Okay. So we could call that just scattering. Okay. So it’s called the scattering process, is not measurement, but what it is, it’s the, you know, the [00:27:00] technical term is they have a direct connection via the time symmetric propagator. You know, that’s if, for people who like the technical details, you know, time propagator connects these two charges and there’s no fact of the matter about which ones an emitter, which ones an absorber. They’re simply field sources and they interact this way, but it’s non local, and that’s why it kind of challenges, you know, we all have been kind of marinated in our macroscopic, you know, experience that we want things to be causal. We want things to be local and so on. So this theory kind of challenges that, but that’s what forces are in this theory; they are this kind of direct connection.

[00:27:40] Now what’s required for, to have a measurement which is a different higher level kind of interaction is that we have objects such as maybe atoms that have internal energy states. So rather than just a couple of electrons, we need some structure. We need some additional [00:28:00] structure such as say hydrogen atoms. Okay. So take a couple of hydrogen atoms and take one that’s excited, in an excited state, so that its electron is, you know, at a higher energy level. And then another one that’s at a lower, say a ground state. Well, now we have the potential for a measurement, for a transactional process. And, it’s again, it’s indeterministic, but this is where our decay rates come into play.

[00:28:27] So there’s a, a clearly defined probability for any particular time that these two atoms will go, hey, we’re gonna do this non unitary; we’re gonna elevate our interaction from simply force based, to be able to transfer energy. So we here, we distinguish energy from force and we get the emitter emitting an offer wave, and we get the absorber responding to that. And if we have more than one potential absorber, then we get a [00:29:00] bunch of them responding. But this isn’t really real energy. It’s kind of the possibility for energy. So, what we’ve got is say, suppose we had three eligible ground state atoms that could absorb it. They would all respond with what would be represented by a projection operator again.

[00:29:19] So we’d have our measurement transition, our mixed state, but only one of these could actually get that hunk of real energy, that is the photon. So there’s sort of two stages to the measurement transition. There’s the response; there’s the initial, non unitary interaction that involves this kind of response and the creation of this set of weighted possibilities that have well defined probabilities. And then there’s a collapse to one of them. So, you know, it’s kind of, it’s a lot of words, but it’s very clearly… you can quantitatively define it. You can, you know, the probability that’s going to happen at any particular time and so on.

[00:29:59] Al Scott: This is [00:30:00] very interesting. So, collapse of the wave function is still to a random possibility amongst the options weighted by the the probability of these things.

[00:30:12] Now, this has been used by a lot of people that I’ve talked to, this randomness in quantum mechanics as a place to hide the will of the gods, or the place to hide volition and free will and consciousness, you know, it hides in this randomness of the quantum mechanical measurement, the indeterminacy of quantum mechanics.

[00:30:30] So does the transactional interpretation close this gap? I guess the gap still is there. There’s still no explanation as to why one is chosen over the other.

[00:30:39] Ruth Kastner: That’s correct. It is. And that’s what you get with genuine indeterminism. So, I mean, rather than the term randomness, I like to just use indeterminism there that’s no, that there’s a, it’s a one to many kind of transition. You get, you know, some prepared state transitioning to several, you know, or many different [00:31:00] possibilities. And I mean, this actually does happen elsewhere in physical theories. You have what’s called spontaneous symmetry breaking in connection with the Higgs mechanism where you have a bunch of different possible vacuum states for the field and there’s kind of no explanation, there’s no causal account for why one of these gets realized. So we do have this elsewhere in physics. So, you know, I always point that out when people kind of say, well, you haven’t solved the measurement problem cuz you haven’t explained, you know, why I got this one outcome. And so the point is, well, that doesn’t mean we haven’t accounted for what measurement is and so on because you have the same situation elsewhere in physics with spontaneous symmetry breaking.

[00:31:42] So I mean that’s one way to understand it. I’ve written a little bit on this point, although I definitely don’t focus on it and don’t claim to have any special expertise in, you know, in issues of free will and so on. But I do think it’s true that if, you know, your world were [00:32:00] completely deterministic, then… I dissent from the idea that, you know, people who call themselves compatible will say, you know, things like, well, free will is compatible with determinism. And, you know, I dissent from that because if physical law is deterministic, and the initial conditions of all our physical laws were set up, you know, way before we were born, then how could anything that we do possibly be up to us. Right? And it’s just sort of, whatever’s gonna happen is literally predetermined. So I’m, you know, I really don’t think compatiblism works at all, and I think it’s kind of a form of denial. However, you know, if the world really is indeterministic, if physics really is at a fundamental level indeterministic, then that’s the only thing that could possibly be, I think, you know, in my view, an entry point for volition. Where else could it come in? You know, I’m not sure where else it would come in. [00:33:00] So, you know, if those of us who do think we have free will, you know, this is good news. I mean who knows how that gets implemented? I don’t claim to, you know, be able to explain that, but certainly there’s at least an entry point where whatever happens in the future is clearly not fated if physical law itself will not tell you, is unable to tell you what’s going to happen. So either nature chooses or, you know, many famous physicists have talked about choice or nature, choosing, Freeman Dyson has talked about that. So it seems that at some level, you know, some kind of a-causal, if you will, process is happening that could correspond to volition at some, you know, in some way.

[00:33:46] Al Scott: I struggle philosophically with this whole thought about free will and determinism because I’m kind of on the fence in all of this. Because if indeterminism allows free will, [00:34:00] then we should be able to influence the probabilities of quantum mechanics with our free will. And I’ve never seen an experiment that can show that.

[00:34:08] Ruth Kastner: Oh, actually though I don’t think that necessarily follows. So, the idea that because you know, that the fact that we might be able to choose, given suppose we’ve got three places for a particle to be,three boxes or something, and we can somehow precipitate, you know, box A, that doesn’t necessarily mean we’ve influenced the possibility. But I mean, it’s a subtle point and I’ve written, I actually have written a paper about this very point, so I could give you that it’s I can dig it out and, and give you that. And we can, you know, at some point, put it in the chat or, you know, put it in some comments for people who want, who wanna look at that.

[00:34:47] One, one place to start is a, a paper by. Clark I’m forgetting his first name Randolph Clark? Anyway, I will dig, it’s in my paper. And he has this wonderful paper entitled “are we [00:35:00] free to obey the laws?” So it’s sort of like, can you have freedom? Is there situation where, you know, someone has different choices they can make that have to be distributed according to some probabilistic law, but for any given instance, they can choose, you know, which outcome is going to be realized as long as the distribution ends up being in accordance with that law.

[00:35:27] And, you can do that. I mean, you can actually do that. So the idea is, you know, it doesn’t necessarily require in order for us to kind of take advantage of this loophole and have free will and say, okay, the, the quantum probabilities are such and such, and therefore if I choose, I’m going to change them. And it actually doesn’t follow. Another reason it doesn’t follow is that at the level of the kinds of macroscopic situations that people would be involved in, it is not the case that well-defined quantum [00:36:00] probabilities apply to those.

[00:36:02] So let me try to see if I can explain this. So suppose, you know, we’re talking about a typical choice, like, well, should I have coffee or tea, you know, after dinner? Okay. Well, it is not the case that there are well-defined, quantum-born rule probabilities for those choices. In fact, there are a bunch of different brain states, different environmental situations that are in play for corresponding to that choice. So the only, you know, the idea that every… this is another mistake that people make, they’ll say well, take the case of Hitler. Okay. So Hitler is terrible example. I don’t know why he came up with that, but so, okay. So for the quantum probabilities, applying to Hitler are, you know, 90% invade Poland, you know, 9% invade France, 1% become a ballet dancer. Okay. So if Hitler could really choose freely. [00:37:00] Then, you know, the idea is that Hitler must be a slave to these probabilities. He has to be bound by these probabilities. So therefore he doesn’t really have free will in some sense. But in fact, these choices are not described by quantum observables, right? In order to get a born rule probability, you must have a well-defined quantum mechanical observable that corresponds to a particular, you know, set of degrees of freedom, and you just don’t have that. At the macroscopic level for people like Hitler or, you know, people deciding what beverage to have there’s no well-defined quantum observable in play. So the idea that we are slaves to the probabilities I think is really overstated. And I think that there’s a genuine, you know, entry point to have where we’ve really got indeterminism. And that’s our entry point for volition.

[00:37:55] Al Scott: Yeah. The fact that the indeterminism allows for different [00:38:00] futures is effectively the argument that allows us to influence with our free will, the future. Versus determinism where, you know, the future is set and we cannot change it so it appears we don’t have free will, even though the things we are doing are in line with our volition or our wants and needs. I think Bertrand Russell had a very good description of, you know, determinism doesn’t get rid of free will. You are still acting at your own volition. I mean, nobody can predict the future. There’s chaos, there’s [order].

[00:38:32] Ruth Kastner: Did Russell say that? Sounds like that’s a compatibles argument and I’m like, well, no, I’m sorry. If the laws of physics are truly deterministic, then the so-called volition that, you know… I really want some tea, so I’m just gonna choose tea. Well, no, I’m sorry. According to the assertion, if one is going to assert determinism, then one must assert that their desire for tea has been determined by physical law[00:39:00] and it’s not up to you, you know? So I just, I just see people wanting to have it both ways. I have to go back. I don’t know, you know, I don’t wanna be like saying Russell was refuting himself unless I know that, but this is a standard argument.

[00:39:14] I think there’s a philosopher named Stamp. Who made this sort of argument that, you know, well, compatiblism; okay, if no one is coercing you, you know, then you have free will. If you’re not actively constrained, then you have the free will to act in accordance with your desires or something. But again, this is trying to have it both ways. Cuz if one believes, if one is going to assert determinism, then one’s desires are simply determined and we’re just dominoes, right? I mean, that’s the domino picture. So, you know, I don’t believe the universe is deterministic, so that’s not a, you know, that’s not a problem for me. But if someone wants to assert determinism, then really they’re just saying we’re sentient dominoes. Cause you know, initial conditions, deterministic laws… [00:40:00] I’m sorry folks, there’re no live choices because the laws decree unique outcomes in everything. So I just, you know, I kind of go in a chair about that cause, a lot of people just really wanna have it both ways. So I mean, I’m happy to learn, you know, I get told that I’m caricaturing compatiblism, but again, I just, you know, I’m receptive to being challenged on that, but it does seem as though if you’ve got determinism, you’ve basically got people being sentient dominoes.

[00:40:33] Al Scott: Yeah. I’m not the greatest proponent for this either. I’m not a, you know, I’m not a philosopher, but , I’m very interested in all of these arguments and I haven’t, as I say, I’m pretty agnostic at this point. I’m learning all the time about a lot of these positions and it’s quite interesting to see.

[00:40:49] How has the reception been for transactional interpretation in the physics community? Is, is it, is it picking up steam? Is there a large group of support or is it [00:41:00] relatively new to most people?

[00:41:01] Ruth Kastner: I think it’s picking up steam. It’s sort of the little engine that could. My husband happens to be really interested in steam locomotives so it’s a metaphor that I[use]. He does these live steam trains, miniature trains that actually run on live steam.

[00:41:15] But anyway, it has the kind of stigma of, you know, Wheeler and Fineman who were among the original proponents of this absorber theory. Both kind of walked away from it at some point because it didn’t really serve their purpose at the time, but it, it does work. And it’s simply that, you know, I go into this in some detail in my book that, that it didn’t serve the purpose they were pursuing it for, and so it does have this kind of stigma, you know? Oh, these smart guys, you know, didn’t continue with this theory. And it also does have the non-local direct connection, which is viewed suspiciously, you know, action at a distance and that kind of thing.

[00:41:52] So it is gaining some more, maybe not acceptance, but interest. So I think it’s, it’s starting to be [00:42:00] considered a little bit more, broadly, which is nice. And I mean, it is true that back in about five years, I think before Wheeler passed away, he actually came back to it and started saying, you know, absorber theory may have promised for quantum gravity and so on. So it does have to overcome some amount of stigma due to its historical status and the kind of you know, counterintuitive features that it has.

[00:42:28] Al Scott: Well, yeah, and I kind of like the grandiosity of the many world’s theorem to a certain extent and this kind of slays that, gets rid of all those other universes.

[00:42:37] Ruth Kastner: Well, yeah, the many worlds thing, I think you know, was a noble effort by Hugh Everett to to kind of bite the bullet of, you know, look quantum theory, you know, if you really think that it only has this unitary evolution, which is what people kind of tend to think that it really only has unary evolution, then there’s no real collapse. And he kind of, [00:43:00] you know, wanted to be honest about that and say, okay, well then there’s no collapse. Let’s explore that.

[00:43:05] But it, you know, it just doesn’t really work because it does not lead to the kinds of empirical, you know, fruitfulness, that it doesn’t really predict what we see. And in order to kind of get the born rule out of it, you have to, you kind of use circular argumentation and have kind of a preferred basis for how the world splits and kind of smuggle in classicality, you know, and, and it, it gets a bit circular.

[00:43:31] So I just think it really doesn’t work. And I think that it’s important to, in order to make progress with these kinds of the increasingly bizarre, paradoxical situations that people are coming up with, you know, and we really get kind of inconsistencies happening now. And those are not, I’ve argued, you can’t really get around them in the many worlds picture, because you end up just kind of hand waving and saying, oh, where is splitting gonna happen? And why should splitting happen for this [00:44:00] interaction, but not for that interaction. And it becomes kind of ad hoc. So I do think, you know, that there is real non unitary that the technical term, meaning this transition from just the mere kind of force-based deterministic process to the in-deterministic process. This is really happening in nature. And, and the transactional formulation is the only one that, that gives you kind of a natural physical basis for that without having to kind of Jerry rig quantum theory and put in, you know, ad hoc kinds of things.

[00:44:36] Al Scott: This sort of providing objective criterion for, for de coherence or for collapse pops up in a lot of theories.

[00:44:42] I know Penrose has his objective reduction theory as well, and he tries to tie in quantum gravity to the criteria for col for an objective collapse criterion effectively. And do so for these ones that, I mean, you could envision a [00:45:00] reputation or an experiment where you could try to put macroscopic things into super positions.

[00:45:04] Are there any efforts. Going towards these sort of experiments or any realistic hopes that something could happen to, you know, try a reputation or, or experiment and dis discern between some of these.

[00:45:19] Yeah, I think, I mean, again, for, for the transactional picture, it is empirically equivalent at the level of the born probabilities.

[00:45:27] Cuz as you know, as we’ve talked about it, derives those. So and, and what you get with ti again is, is that it, it resolves the anomaly of failing to get measurement in the standard theory. However, for these other col explicit collapse theories, they do seem to deviate. They do deviate, I think, and I’m not expert on that.

[00:45:48] I ha you know I, I happen to think the Penrose’s, you know, approach a, again, it is very nice to look for some real non UNITAR in nature, rather than just using your, you know, [00:46:00] observers as, as your placeholder for, I don’t know what, right. I don’t think that’s really the right way to go, cuz I do think that that gravitation is an emergent, basically the structure of space time that emerges from measurement and that that’s what I’ve argued.

[00:46:14] So I don’t think you can kind of use gravity. To do that. And, and I think that’s why they’re get, they’re getting I mean, you know, who knows again, if it is falsifiable then, you know, or, or if it is something where, where it could be corroborated. Well, that would be good information. I do think that from what I’ve heard, there are some perhaps, you know, experiments that are being contemplated that might be able to distinguish the Penrose model, you know, that, or, or falsify it.

[00:46:45] So, and I do think, I do think for the other explicit collapses, because they do have to change the theory. They have to change the dynamics that does change the probabilities to one degree or another. So, so for those theories, which I view as kind of ad [00:47:00] hoc, I view them as kind of ad hoc changes to kind of force collapse.

[00:47:03] But it, but it is, I believe, you know, the case that that’s what they’re aiming for to, to get a test like that

[00:47:11] you, you mentioned in passing that you’ve, you’ve worked on. Your theory of this is saying that gravity is emergent from the, from this picture that, so, and, and time these are timeless type of interactions.

[00:47:26] You’ve also mentioned that. So, so are you thinking that relativity, relativity and, and gravity and all this stuff kind of emerges as something that’s not basic that the quantum mechanical structure is the basic thing, that structure of reality and, and relativity emerges then from this as a, as a consequence?

[00:47:48] Ruth Kastner: Exactly. Yes. I mean, I’ve, I’ve argued kind of in a metaphorical way that, that what we call space time is kind of the tip of the ice. So that, so the idea is that yes, the [00:48:00] fundamental reality is, is what I call a quantum subs, stratum. That’s kind of a precursor domain to space time. And that, that what we call space time is really kind of a construct that is the the results of measurement interactions.

[00:48:16] So those actualized measurement events, that would be the mission event, the, the actualized emission event, the actualized absorption event. So the, the, the absorber that kind of won that photon, and then the photon becomes like an element of space time. It connects. It actually connects the emission and absorption event and it it’s an interval, so it defines an inva interval.

[00:48:42] So, so whenever we’re do, whenever we got this measurement interaction and this actualized transaction, we get a new element of space time. It’s kind of a link. So it’s not just an isolated event. They’re always, they always come in pairs. They always in an emission event, absorption event and that [00:49:00] structure.

[00:49:00] So that structure is just gravity. Okay. So the idea is that, that the, the metrical properties of space time that that are described by general relativity are, are emergent from this transactional process. So this kind of gives us a way forward for, for a quantum theory of gravity, which I don’t claim to have, but I’m working with a colleague right now.

[00:49:25] Andrea Schlater who has already done some work on, on a version of, of quantum gravity. It, it takes off from what’s called entropic gravity. That was pioneered by Eric Lin. And he did very interesting work. He’s still working on it with the idea that, that, again, that, that space time with its metrical.

[00:49:50] Properties that are, that is GRA GRA that’s. All gravity is, is the metrical structure of space and time, space, time. So then he, he showed that this [00:50:00] is really kind of an emergent property that has this entropic character, that, that the attraction of gravity is, is basically that just simply that certain things are more likely to happen when you have areas of higher entropy.

[00:50:16] So that, so that what looks like a, a mass moving toward another mass is simply a series of, of events that actualize these two masses in a way that they’re constantly getting closer because that’s like the philanthropically favorable state. So it’s, it’s a really interesting way forward that that Andreas and I are working on fleshing out in this transactional picture.

[00:50:42] Al Scott: I really like Berlin’s idea of, you know, basically just the volume of space gives you more states. So you have this entity which is associated. Masses that are far apart and very elegant theory.

[00:50:57] Ruth Kastner: It is. It’s, it’s wonderful. It’s a very [00:51:00] elegant theory. And, and so we’re, we’re working with that and we kind of think that, that the idea of transactions helps to explain kind of the information content there.

[00:51:09] There’s sometimes there’s a little bit of hand waving about, well, why is the entropy, you know, have this character, why is your larger entropy, you know, around, in closer proximity to, to, you know, when the masses are closer together. So you there’s some work to be done to, to kind of quantify that. But, but the idea that, that the, the space time construct is, again, it’s not a con in our picture, it’s not a container.

[00:51:33] I mean, that’s kind of what, what we’re up against in, in the kind of what we need as a paradigm shift here, because we, we, we all kind of grew up thinking. That the word space time means container for everything that’s real container for everything physically real. And so, so in, in the picture I’m working with, that’s really not the case.

[00:51:54] And in fact, a lot of what’s real is, is not in any sort of space time [00:52:00] container. It’s, it’s a kind of a, if you will, it’s a domain of possibility that gives rise to just really just this kind of tip of the iceberg manifold, that, that, that is space time. And that’s really just a set of a structured set of events that, that we can be corroborated so that we can send signals.

[00:52:20] And, you know, we can all corroborate that yes, this event occurred and we can give a a well coordinated, consistent description of, of an event through the use of communications, you know, involving light signals. So that’s, that’s kind of what the space time structure is, but it’s not a contain. For everything.

[00:52:43] Al Scott: Wow. I’m just rearranging my mind now.

[00:52:47] Ruth Kastner: Yeah, it kind of, it does kind of turn your mind inside out. And I, I do talk about the, these these more recent developments and my second edition that, that just came out the Cambridge university press [00:53:00] that the first edition was, came out in 2012 and it was called the transactional interpretation of quantum mechanics.

[00:53:06] Subtitle was the reality of possibility. So this one has the same main title, but the subtitle is now a relativistic treatment because it, it I’ve, I’ve developed it a lot more in terms of the specifics of the relativistic features of, of the interpretation, because it really does go beyond the, the Kramer version on it.

[00:53:28] And, you know, in a very, very specific ways. And it, and I do have a chapter now on this idea of, of measurement via transactions. As the mechanism for the emergence of specific space time, you know, units of space time, and, and how does that work and, and so on. So it, the, the book has different kind of levels and the, the first half or so is, is more conceptual and, and hopefully fairly accessible in, in talking about the general concepts.

[00:53:59] [00:54:00] But then the later chapters get a bit more technical and, and so on, but I believe chapter eight is the one that has the information about you know, this idea of space, time as, as emerging.

[00:54:12] Al Scott: Yeah. I love, I love the, the thought of this because it does, it fits well with relat and relativity and time dilation.

[00:54:20] You know, if you think about photons and relativity and, and time dilation, anything that travels at the speed of light moves from one point to the other, without any local time passing. So these transactions. Happen, instantaneously from the point of view of the photon, the photon doesn’t traverse space in its own frame.

[00:54:40] It, it is just at one particle and at the next particle, this is the framework that, that holds the universe together. That’s that’s I love that. It’s good.

[00:54:50] Ruth Kastner: Yeah. And it’s only from, from different inertial frames that it, it, it, it seems as though sometime has elapsed between emission and absorption, but again, [00:55:00] as far as the photon’s concerned, no.

[00:55:01] Okay. Well, these are just, these events are connected really from the point of view of the photon. So it’s, it’s only from, you know, the point of view of, of systems that have non vanishing rest mass. That, that there’s an experience of a time lapse. And again, that’s not an inva, you know, thing at all. It it’s, it’s depends on your, your relative motion. How, what kind of, you know, time lapse you’re going to record.

[00:55:29] Al Scott: Well, I think we’re, we’re getting towards the end of our time slot, and this is been really interesting, and I really appreciate you taking the time to explain all this to me and, and, and our listeners in a way that we can understand it.

[00:55:39] It’s been great. I have one last question that I ask a lot of my contributors and I’m, I’m interested to hear what, what kind of science fiction do you like to read?

[00:55:51] Ruth Kastner: Oh, science fiction. Well, it’s been so long since I’ve read science fiction. But I’m an Arthur C. Clark fan. I mean I do like [00:56:00] science fiction.

[00:56:01] I, you know, I’m not much on kind of the classic literature. My sister’s a poet and she’s the English major and she’s know. Yeah. I guess Arthur C. Clark, “the city and the stars” was one of my favorite novels. And back when I was, you know, a little kid, I guess I was around 10 or 12, my back then they called it junior high school.

[00:56:21] Library had this wonderful story called “the star seekers” by Milton lesser. And it was, it was just a wonderful story about basically I don’t wanna give it away in case any of your viewers wanna, but I, you know, definitely look it up the stars seekers. And it was, it was about basically kind of a journey, a multi-generational journey of people going from, from, I guess, the earth to some, some you know, extraterrestrial home and a great, great story.

[00:56:53] Great, wonderful story. So, and I I’m a tracker I, I like star Trek and I, I like Babylon [00:57:00] five. Mm

[00:57:02] Al Scott: Yes. It’s got very good reviews, indeed. So, thanks again for coming on. I’m gonna send you a rational view t-shirt for taking the time to, to chat with us. So it’s been a pleasure chatting with you. I hope I hope we can talk some more about some of the philosophical implications of this theory and look forward to learning more about it as we progress. Thank you.

[00:57:21] Ruth Kastner: I’d love to thank you again for the invitation. It’s been fun.

[00:57:27] Al Scott: If you’d like to follow up with more in depth discussions, please come find us on Facebook at the rational view and join our discussion group. If you like what you’re hearing, please consider visiting my patron page at patron.podbean.com/therationalview

[00:57:44] Thanks for listening.

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