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Welcome! Here you will find information about the latest, relativistic version of the transactional interpretation of quantum mechanics, ‘RTI’, blog posts, and an opportunity for informal discussion. The transactional interpretation (TI) is a new way of understanding what’s behind the formalism of  quantum physics.

My new book for the general reader, Understanding Our Unseen Reality: Solving Quantum Riddles, was published in 2015 by Imperial College Press. UOUR.cover

Here is link to my 2012 book, The Transactional Interpretation of Quantum Mechanics: The Reality of Possibility  

Preview material from the above book: chapter 7

I recently joined the Starytime Podcast to discuss TI. That episode is available here:http://starytime.weebly.com/stary-time-podcast/episode-008-dr-ruth-kastner-unseen-realities (interview begins at 15 min)

You can listen to an introductory talk on TI and the Measurement Problem at Exelis, Inc. here: Introduction to PTI Here is the accompanying Powerpoint: The Transactional Interpretation

Some of my papers: The Broken Symmetry of Time

On Delayed Choice and Contingent  Absorber Experiments

PTI and Relativity

Here is part 1 of a podcast/Minilecture entitled “Appearance and Reality 1,” created for an extra-credit conference in an online Science and Religion course. It is an introduction to metaphysical questions relevant to the interface between science and religion. Here is part 2 of this minilecture: Appearance and Reality 2

The Serious Flaws In the Popular Dismissal of Free Will

Let me begin by stating up front: I do not claim to know whether we do or do not have free will. We may have free will, or we may not. The only strong claim I wish to make here is the following: if we do not have free will, it is not for the inadequate reasons presented thus far. Since neuroscientist and anti-free-will polemicist Sam Harris has been among the most prominent of standard-bearers for the claim that we lack the power of volition, I will focus here on his arguments as summarized in his book “Free Will.”

The Libet Experiments Do Not Show that We Don’t Have Free Will

Harris begins by asserting an all-but-discredited[1] interpretation of a famous experiment by Benjamin Libet that appeared to show that our physical ‘wetware’ brain causes our decisions before we become consciously aware of them. This much-repeated claim that we passively and unconsciously do whatever our brain tells us to do rests on a highly fallible understanding of the processes underlying spontaneous decision-making, which has been called into serious question [Schurger, Sitt and Dehaene 2012] and apparently refuted by subsequent experiments [Herrmann et al 2005]. For example, Schurger, Sitt and Dehaene (2012) provide an empirically tested alternative model of the measured neural activity preceding a decision and note that:

“Libet et al.’s findings …. suggested that the neural decision to move happens well before we are aware of the urge to move, by 1/2 second or more. According to our [empirically corroborated] model, this conclusion is unfounded. The reason we do not experience the urge to move as having happened earlier than about 200 ms before movement onset is simply because, at that time, the neural decision to move (crossing the decision threshold) has not yet been made.” [my emphasis]

Besides Libet’s prejudicing assumption that volition must be tied to ‘urges’–a debatable notion–more decisively refuting Libet’s interpretation of his experiment was the experiment of Herrmann et al cited above, which showed that the brain’s electrical ‘readiness potential,’ taken by Libet as causing a specific choice, was present in the absence of any choosing situation. It was simply part of a preparation for readiness to respond to an instruction (whether to push a button with left or right hand). Since the subjects always pressed the correct button as instructed (after the RP appeared), their brain did not tell them which button to push.  Therefore, contrary to popular belief (whose continuing popularity may be in large part due to Harris’ promulgating of a claim multiply refuted by his own community of neuroscientists), it has not at all been scientifically established that a choice is caused by the physical brain prior to the chooser’s awareness of the choice. If anything, neuroscience has since shown that there is probably no basis for that claim.

A False Dilemma

Harris then turns to some questionable (even if much-repeated) arguments against volition in the literature. He first repeats the standard argument for what is called ‘incompatibilism’; this boils down to the idea expressed succinctly by Peter Von Inwagen in his Essay on Free will (1983):

“If determinism is true, then our acts are the consequence of laws of nature and events in the remote past. But it’s not up to us what went on before we were born, and neither is it up to us what the laws of nature are. Therefore, the consequences of these things (including our present acts) are not up to us.” (p. 56)

I happen to agree with this assessment–thus, I could be called an ‘incompatibilist’. That is, I agree that under determinism, all our actions are the necessary and unique results of causes that must ultimately be beyond our control. (However, it should be noted here that there are those called ‘compatibilists’ that argue that we can still have free will under determinism. That argument greatly depends on what we mean by ‘free will’. I will not go into the subtle issue of defining free will here, and will just work with the definition that I think Harris has in mind–in which it’s understood that our choices must be ‘up to us’ in some robust way. One way to put this is the idea that we ‘could have chosen otherwise’ than we actually did.)

But then Harris repeats what amounts to a false dilemma.[2] He tries to argue that not only can we not have free will if determinism is true; we cannot have it even if determinism is false. That is, he rules out free will even in the case of indeterministic laws (i.e. laws that do not completely dictate what must happen given a specified set of events). He asserts that indeterminism fails to allow us free will because of his worries about the apparent inability of science to identify what the ‘Self’ is, and to confirm that it allows us be the ‘author of our actions.’

Specifically, Harris decides, based primarily on his own personal introspections, that because he doesn’t seem to consciously generate his thoughts, that none of his thoughts really belong to him. Therefore, he muses that none of the actions he takes based on those thoughts can really belong to him either; and he instructs us that we should agree with his assessment because (he believes) it’s obviously true.

However, none of Harris’ assessments and conclusions about the relation of his Self (if any) to his thoughts and actions is so obviously true as he seems to think (or–in Harris’ terms–as the thoughts that don’t belong to him (!) seem to imply). A major problem with his conclusions is that they are based on certain unstated presuppositions that he appears to take for granted, but which are not at all necessarily true. Specifically, he uncritically presupposes that in order to be the ‘author of our actions,’ we must either

(i) consciously generate the thoughts pertaining to those actions, or at least

(ii) always know where the thoughts relevant to our actions come from.

But why should we buy into this formulation of what it takes to be ‘the author of our actions’? Does the author of a book know where his/her ideas come from? Probably not—in fact, especially in fiction works, this is the meaning of ‘inspiration’: the artist ‘breathes in’ the ideas. While we usually think of ‘inspiration’ in conjunction with works of fiction, it holds for nonfiction works as well (indeed, many scientists talk about getting ‘inspiration’ for a new theoretical idea or scientific endeavor). Yet according to Harris’ own arguments, he is not the author of his own book. Should we really grant him this extreme degree of modesty regarding the product of his labors?

Harris does not appear to have considered the possibility that the thoughts and ideas that come ‘unbidden’ to us are like visitors that come to our door. We still have the choice whether to welcome them into our home or not, and whether to take them on as the comrades, instigators, inspirations, or all the other things that that they might prove to be.

Nevertheless, it’s important to note that not all thoughts are wholly ‘unbidden’ in this way. Some thoughts are clearly ‘bidden,’ as any scientist ought to know. Einstein searched and searched, and worked and worked, until he came up with the ideas that he developed into the Theory of Relativity and other groundbreaking theories (including vital components of quantum theory). Werner Heisenberg clearly ‘bid’ the insights that led him to formulate quantum theory. The annals of scientific discovery are replete with instances of ideas having arrived in the minds of scientists as a direct result of their fervent searches.

Of course, Harris would likely dismiss all of that by saying “the curiosity that led to their questions that led to their searching was also unbidden.” But if so, he enters a kind of reductio ad absurdum. Such a reduction of all creative endeavors to knee-jerk passive reactions to causes outside ourselves would seem to nullify any vestige of meaning or value to human life (or any other sentient forms of life for that matter). If active engagements–like curiosity, perseverance, and enthusiasm–are actually no more than passive reactions to causes and forces, then it becomes very difficult to argue for any sort of value or meaning. “The marionette exhibited behaviors characteristic of curiosity.” Nobody cares about a marionette’s utterances–it has no intent or motivation, and it gets no blame or credit for anything it does. It is clearly not a person in the meaningful and vital sense that we all take ourselves (and hopefully each other) to be. Thus, calling oneself a marionette–as Harris effectively does–is essentially self-refuting.

Yet Harris seems anxious to retain some vestiges of meaning and value at the conclusion of his book, where he considers what we should say to people about their alleged lack of free will in order to best ‘serve’ good and valuable ends in society.  Even apart from whether or not he would discount the intent of a scientist to seek and to make active use of inspiration as playing a role in the kinds of thoughts he or she entertains, it seems inconsistent for him to speak as if we have live options about what to say, what to believe, and how to behave. For he has spent his entire book arguing that we are puppets on strings–as depicted on his book cover.

Now, it could turn out to be true that we are just sentient marionettes. But the point is that failing to be able to explain how volition could work is not a demonstration of that. If (based on an actual sound proof–which Harris has not provided) it did turn out to be true, then we would need to face up to the fact that we don’t have live options about what to think and how to behave, and stop trying to have it both ways–as Harris seems to want to do. If we are sentient puppets, that’s all we are: we have no live options; we create nothing that wasn’t already created by whoever/whatever holds our ‘strings’; nothing is up to us; and if someone wants to retain notions of value and meaning in that face of that, they’re going to have to do better than to just presuppose it, as Harris appears to do towards the conclusion of this book. (Of course, I recognize that this is a key motivation of the compatibilist approach; but I remain skeptical of its success.)

The Self as Active Custodian of a Point of View

As a self-described meditator, Harris should know that meditation presupposes that one has a live option of attending or not attending to thoughts. During meditation, thoughts come to us unbidden. The practice of meditation consists in making a choice to disregard those thoughts when we notice that we are having them, and to return to the mantra or to whatever other focus is the vehicle of the meditation. By taking the position he does against the idea that we have any real volitional power, Harris discounts the essential nature of meditation.

In any case, during meditation, Something becomes aware of the thoughts; and then that Something chooses to disregard them and to attend to something else. This “Something” is what we can identify as the Self. How does this work? I do not claim to know. However, it needs to be stressed that, as a purely logical matter, the burden of proof of impossibility claims is on those making the claims. No reputable mathematician will state that because he has not been able to find a proof of the existence of a mathematical entity, it cannot exist. Being unable to conclusively demonstrate the existence of an entity or mechanism or function is completely different from having demonstrated that it cannot exist. Yet what we see in Harris’ discussion of the issue is a narrative of his unsuccessful attempts to understand how the entity or mechanism or function of free will could exist–that is all. For Harris to infer from his lack of success in this endeavor that it cannot be done is to commit a serious logical fallacy (since failure to find an existence proof is logically inequivalent to having found a non-existence proof).

Moreover, as noted above, Harris does not appear to have considered the possibility that the choosing Self is the sentient and active custodian of a point of view. Thoughts may arise from a seemingly mysterious and unknown source according to that point of view, but that does not rule out the fact that Something–to which we feel intimately connected–routinely decides whether or not to pay attention to those thoughts and/or to act on them. In fact, I believe that this “Something” is what Descartes was referring to when he rejected all doubtable knowledge and was left with only that aspect of himself that was a ‘thinking thing’. If, like Harris, we want to go farther and assert that the thoughts are not necessarily generated consciously by that ‘thinking thing,’ then it is really a ‘perceiving thing’–but it is still an actively choosing, perceiving thing.

Note above that I italicized “according to that point of view” (of our choosing Self). Is it possible for us to expand that point of view, and to gain more awareness of where those thoughts come from? (Harris does not seem to have considered this possibility either.) While I do not pretend to possess any special knowledge of this issue, we might look to philosophers of mind, to psychologist Carl Jung (who posited a nonlocalized ‘collective unconscious’ as well as our localized centers of consciousness), as well as to various spiritual traditions (e.g. Buddhism, Western Esotericism) to learn more about this possibility. I believe that this is where much of the interesting work lies in order to understand better what we can mean by the “Self” and what role it may play in the actions we undertake from a sense that we are acting freely.

Thus, Harris’ presentation (besides relying on the repeatedly refuted experimental inference of Libet and his followers) is not much more than a tour of his own unsuccessful attempts to figure out how volition could work in view of the fact that he cannot figure out where his thoughts come from, and how he could be the ‘author of his actions,’ given that observation. Now, this would be acceptable as a narrative of personal introspection, except that he goes beyond that to elevate his own inability to discover or understand how volition could work (based on his formulation of the problem that might be flawed or unduly restrictive, as noted above) into a dogmatic pronouncement that it obviously cannot work, and that others would be foolish to try to think that it could.[3] Besides being a basic logical fallacy as noted above (i.e. equating the lack of a demonstration of existence of free will to a proof of non-existence of free will), this is a form of arrogance reminiscent of the plentiful dogmatic pronouncements against advances and discoveries that have subsequently been refuted by people with more imagination and creativity[4] than the people who uttered them (e.g., “If man were meant to fly, he’d have wings” and many other examples).

Moreover, there are real adverse social consequences for leading people to believe that they lack free will (http://journal.frontiersin.org/article/10.3389/fpsyg.2014.01483/full ). So this is not just an ‘academic’ question, and it is irresponsible for authority figures to promulgate the idea that everyone lacks free will when they don’t really know that this is true–and are disregarding scientific findings (even in their own field) in order to maintain their dogmatic negative claims on the matter. (The article cited above begins by acknowledging that “Weakening belief in the concept of free will yields pronounced effects upon social behavior, typically promoting selfish and aggressive over pro-social and helping tendencies,” and describes an experimental finding in which subjects primed to believe that they lacked free will exhibited a diminished sense of personal agency of a specific kind.)

Finally–while this certainly has not been established—it may turn out that the question “What is the Self and its relation to ideas, actions, and volition?” is a question beyond science’s ability to answer. But that does not make volition ‘anti-scientific’ (a pejorative notion). It might make it extra-scientific. To assume that an inability of science to solve a problem must imply that the problem is unsolvable would be a form of scientism—which is itself an extra-scientific notion.[5]  

[Postscript: After writing this blog, I became aware of Robert Doyle’s page on Sam Harris, which makes very similar points regarding weaknesses in Harris’ arguments: http://www.informationphilosopher.com/solutions/philosophers/harris/     For example, Doyle asks: “Does Harris really believe he is no more responsible for being the author of his book than for his birth? His choice to write it was the cause of its being – even if it appeared in his mind sprung from the void, right?”]


[1] There is probably a consensus that Libet’s interpretation is discredited; however to avoid an impression of overstating my case, I leave that to the reader to decide, based on the references.

[2] Harris is by no means the only one to claim that indeterminism doesn’t allow for free will either. While I will not address those other arguments here, I address them, at least in part, in this publication.   Harvard astrophysicist/philosopher Robert Doyle has also argued that it is a mistake to conclude that indeterminism fails to allow for free will. He discusses many possible models, and offers a specific model of free will.

[3] In fact, it’s eerily (and ironically) reminiscent of the way in which Descartes relied on his own allegedly ‘clear and distinct ideas’ to make categorical assertions about the existence of God. In adopting this practice of introspection-taken-as-decisive, Harris places himself perilously close to engaging in ‘armchair philosophy’.

[4] Even if those people might not be able to trace (to Harris’ satisfaction) where their superior imagination and creativity came from.

[5] The term scientism denotes a philosophical view that science can answer all possible questions in definitive terms. As an example, if scientific enquiry can find no theoretical or empirical basis for meaning in life, then an adherent of scientism would conclude that life has no meaning. Since scientism is a meta-scientific, epistemological doctrine–not subject to empirical corroboration–it is extra-scientific. For a more in-depth critique, see this essay by A. Hughes. Harris may also be influenced by the writings of philosophers such as D. Pereboom, who has argued that the very notion of free will is ‘incoherent’; or, if coherent, is allegedly ‘inconsistent with seeing human beings as part of the natural world of cause and effect’ (e.g., Pereboom 2001; as described in the entry on Free Will in the Stanford Encyclopedia of Philosophy). This tendentious language presupposes a specific view of what should be taken as constituting the ‘natural world’ and its relation to cause and effect–a topic that is not at all settled, especially in view of the apparent indeterminacy of modern physics, and the fact that there is currently no ’cause and effect’ account of the most fundamental origins of life. The basic lesson is that we should remain skeptical of assessments that any concept or idea is ‘incoherent.’ The very strange concepts (such as violation of the law of the excluded middle) that are the functioning aspects of quantum theory would likely have been regarded as ‘incoherent’ and unacceptable from the standpoint of 19th-century researchers.


Review: Unseen Reality; Kastner

Thanks Quine for your review!


Kastner’s is one of two “most important” books in physics and cosmology that I’ve read (and in my opinion of course) over the past 7+ years, the other being “Singular Universe” by R. Unger and L. Smolin. How many books have I read addressing the subject of “quantum mysteries”? Paradoxes of the “double slit experiment”, “action at a distance”, “the impact of the observer”, and so on. Except for hidden variables, mostly rejected for good reasons these days, all of the *explanations* are either mere speculative descriptions of phenomena taking place independently of their observation, or they explain them away. Dr. Kastner (building on the work of her mentor John Cramer) does actually explain these phenomena without hidden variables! Whether you like her hypothesis or not, it has to be a contender.

“Unseen Reality” is Kastner’s very good explanation for a popular audience familiar with the basic issues of…

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The Arrow of Time from an Overlooked Physical Law

I’m reblogging this as a counterpoint to a recent book by John Gribbin, “The Time Illusion,” claiming that the ‘block world’ picture of spacetime is settled science. In fact, it is not. There is no real physical evidence for the ‘block world’ model, and there are counterexamples to the claim that relativity requires such a model. The inability of the block world to provide a complete explanation for the 2nd Law of Thermodynamics is another reason to keep an open mind regarding alternative, ‘growing universe’ models.

Transactional Interpretation


In this post, I’m going to disagree with the following statement by physicist Sean Carroll concerning the nature of time:

“The weird thing about the arrow of time is that it’s not to be found in the underlying laws of physics. It’s not there. So it’s a feature of the universe we see, but not a feature of the laws of the individual particles. So the arrow of time is built on top of whatever local laws of physics apply.”–Sean Carroll, https://www.wired.com/2010/02/what-is-time/

That is a common position, but it could very well be wrong. Specifically, what could be wrong with it is the claim that the arrow of time is “not to be found in the underlying laws of physics.” That claim comes from ignoring the possibility that there could be real, dynamical, irreversible collapse in quantum theory. If there is such collapse, that provides the missing link between physical…

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More on Entropy and the Arrow of Time

This is somewhat technical. It’s for those interested in the puzzle of how we get the irreversible processes we see all around us from laws that are supposedly reversible. The trick: they are not all reversible. A crucial part of the physics of Nature involves an irreversible step that has long been neglected. The paper is an invited contribution to the journal EntropyClick here to read.



Observation is Measurement, but Measurement is not necessarily “Observation”

“By final [state], we mean at that moment the probability is desired—that is, when the experiment is “finished.” –Richard P. Feynman, Feynman Lectures, Vol. 3

The challenge of defining measurement is evident in the excerpt from Feynman’s famous Lectures in Physics, quoted above–when is the experiment ‘finished’??. This remark arises in his discussion of when to add amplitudes and when to add probabilities, in order to arrive at the correct probability of a particular quantum process:

“Suppose you only want the amplitude that the electron arrives at x, regardless of whether the photon was counted at [detector 1 or detector 2]. Should you add the amplitudes [for those detections]? No! You must never add amplitudes for different and distinct final states. Once the photon is accepted by one of the photon counters, we can always determine which alternative occurred if we want, without any further disturbance to the system…do not add amplitudes for different final conditions, where by ‘final’ we mean at the moment the probability is desired—that is, when the experiment is ‘finished’. You do add the amplitudes for the different indistinguishable alternatives inside the experiment, before the complete process is finished. At the end of the process, you may say that ‘you don’t want to look at the photon’. That’s your business, but you still do not add the amplitudes. Nature does not know what you are looking at, and she behaves the way she is going to behave whether you bother to take down the data or not.” [Feynman 1965 Vol 3, 3-7; original italics and quotations]

We’ve already observed here in previous posts (e.g., this one) that TI provides the process, missing in the standard quantum theory, that triggers the measurement transition and, in Feynman’s terms, tells us when the experiment is ‘finished.’ As Feynman noted, Nature is going to behave this way whether or not you look at something—and TI is what tells us how she behaves that way! (Yet Feynman was not taking into account absorption, so he could not really pin down what makes the process ‘finished.’ ) That process is the response of absorbers. While there can be no deterministic, mechanistic account of what “causes” the final outcome, the measurement problem is solved by TI to the extent that it succeeds in defining what a “measurement” is, and that definition does not require reference to anything outside the theory itself.

We’ll return to the very interesting question of the apparent mystery of the choice of one outcome out of many eligible ones in later posts regarding free will. For now, we’re going to focus on the history of how the concept of an “external conscious observer” became entangled (pardon the pun) with quantum theory in a dysfunctional way, to the detriment of both the study of consciousness and the study of quantum theory.

John Von Neumann and the “Measurement Transition”

It was the brilliant mathematical physicist John von Neumann who put the awkward, but functional, machinery of quantum theory on a rigorous mathematical footing. Von Neumann observed that there seemed to be two different processes at work in the successful application of the theory: (A) the deterministic evolution of Schrodinger’s famous equation for the wave function, and (B) the mysterious indeterministic evolution that occurred during a measurement. While he provided a useful and seemingly correct mathematical description of this Process B occurring during measurement, he could provide no physical reason for it. And indeed, without including absorber response, there simply is no physical reason for it. Since Von Neumann, and everyone else working in quantum theory (except for a few physicists exploring the “direct action theory of fields,” which is the basis for TI) were unaware of the possibility of absorber response, it was concluded by Von Neumann and the vast majority of physicists that “There is no physical reason for the measurement transition.”

Thus was born the resort to the “consciousness of an external observer.” In this form, consciousness was a mysterious and primitive notion, detached from scientific examination, since it was by definition external to the processes under scientific study. Of course, according to TI, Process B corresponds to a specific process under scientific study, so TI does not need to resort to the “consciousness of an external observer” in this way. However, TI in no way denies consciousness! Under TI, the topic of consciousness and subjective awareness regains its place as a legitimate subject of study without serving as an ineffective placeholder for a missing part of quantum theory.

Why is the appeal to an external conscious ineffective? Because there is no way to say where the required “external consciousness” enters. That is, it smuggles in an ill-defined (and arguably undefinable) dividing line between the “nonconscious” things in the experiment and the “external conscious observer.” In the Schrodinger’s Cat experiment, isn’t the Cat conscious? Why can’t he “collapse the wave function”? Why is he just an internal system and not an “external observer”?

This puzzle is the so-called “Wigner’s Friend” variation on the Cat Paradox. Eugene Wigner, a famous physicist, noted that every observer of the box with the Cat becomes himself entangled with the previous participating systems (atom, Geiger counter, vial of gas, etc). So, if Wigner is the one who opens the box, he must be treated by quantum theory as simply a new part of the entanglement, lacking any reason for “collapsing” anything. Appealing to a friend entering the room and looking at Wigner as the relevant “conscious observer” doesn’t help, because then the friend becomes entangled also; and then the friend’s friend, etc. Without any basis for Process B, the chain of entanglement necessarily continues; there is no principled way to say that a “conscious observer” is external to anything, or even what a “conscious observer” is! Yet, since (apart from TI) there is no way around this, the notion of a “conscious observer” as crucial to accounting for measurement results has hung on like a ragged band-aid that has long since ceased to protect the wound.

So we have the following curious situation: owing to the press of history and the long-intractable problem of explaining measurement (without including absorber response), it is now often considered naïve to expect that measurement can be defined without resort to “consciousness.” The failure to solve the measurement problem has been elevated to the “lesson” that “quantum theory is a theory about the observer,” and/or that “quantum theory tells us that consciousness is necessary to collapse the wave function.” While there is truth in the point that the type of outcome that will occur is dependent on how a quantum system is detected—which is addressed by TI, as we’ll see in later posts–the appeal to an ill-defined notion of “consciousness” fails to serve the function for which it is invoked.

Decoherence Fail

Another very prominent way to dispose of the measurement problem is to say that “decoherence” solves it. This approach assumes the so-called “Many Worlds Interpretation,” in which one denies that Process B ever really occurs. The only thing that is supposed to be going on is Process A, the deterministic evolution of all the quantum systems in the universe, all components of one gigantic universal quantum state. The claim is that if one considers only a part of that gigantic state, for technical reasons which we’ll won’t go into here, its mathematical description will be the same as the one that we get from Process B—that is, it will look as though it has undergone the Process B measurement transition, even though it hasn’t.

The notion of “decoherence” is invoked to try to explain why the system we’re looking at will appear to have undergone Process B. Decoherence is the argument that a quantum system is interacting with a very large number of other, distinguishable systems in its environment, and that we are not interested in those other systems, so we just average over whatever they are doing and look only at the resulting description of our system of interest. When we do that, our system seems to be in the state resulting from Process B (basically a list of outcomes with probabilities attached to them.) Then, we only see one of those  outcomes because we are in a particular “branch” of the Many Worlds, the other outcomes occurring in other branches. (Of course, that begs numerous other intractable questions about what it means to be “Me in this branch” as opposed to  “Me in a different branch.”)

If we ignore the troubling questions about which “Me” I am, this sounds like a way to get around the measurement problem. However,  it doesn’t really work. For one thing, the mathematical description of the part of the universe we’re looking at (say our Geiger counter in the Schrodinger Cat experiment) is not exactly a match for the Process B transition—it’s close, but it’s really not the same. (In technical terms, the matrix describing the system has off-diagonal elements, even if they are very small. They need to be strictly zero in order to pass as a real measurement transition.) Another, deeper reason why it doesn’t work is given in an earlier blog post . Put briefly, the whole program is circular: it depends on assuming that the kinds of objects required to be distinguishable, in order to effect the appropriate decoherence, must have been distinguishable from the beginning–before there were any ‘conscious human observers’ around. If the universe was one giant quantum state (with any and all possible quantum entanglement), where did this distinguishability come from? It has to be put in by hand, in a circular and ad hoc way, seemingly based only on our otherwise unexplained experiences as observers.

Thus, standard quantum theory always ends up getting stuck on an ill-defined, primitive appeal to a “conscious observer,” outside whatever it is the theory  is describing.   In contrast, including absorption in the theory allows us to quantitatively explain the conditions for the measurement transition of Process B (even if it is inherently indeterministic). Then consciousness becomes freed from its misguided use as an ineffective explanatory band-aid, and can be considered instead in the more appropriate context of such topics as the “Hard Problem.”  This is the argument that if we assume that all matter is inherently nonconscious (as in Descartes’ conception of matter as pure physical extension and nothing else), then no process involving that sort of dead matter can ever lead to anything conscious.  That is, every aspect of the behavior of such a system is accounted for without its ever having any consciousness or subjective experience.

From this standpoint, it may very well be that consciousness and the capacity for subjective experience is an essential ground to all that is. TI itself takes no position on that issue, which is a metaphysical one. But there would be no inconsistency with TI in taking the fundamental ontology of the universe as consciousness or mental in nature. In such a picture, there would be no artificial dividing line between non-conscious stuff and conscious stuff; all would be inherently conscious. Then the arising of conscious biological organisms would not involve any sudden discontinuity, but would be a process in which consciousness gradually manifests itself in more and more complex and volitionally capable forms, through self-organization. Again, all of that is speculative and open for debate–not part of TI, although certainly consistent with it.

Returning now to the title of the post: TI provides an account of the “measurement transition” from within the theory, by taking into account the response of absorbers. Thus, all we need for “measurement” is an absorber–and this is well-defined in the relativistic version of TI (see this and either of my books for details). Now, observers like humans have absorbers too (our sense organs)–so of course when we interact with quantum objects, we trigger the measurement transition! This is why we can see, e.g., a single photon from a light source like the Sun. But the fact that we are ‘human observers’ is not what is required for that transition. Being a human being is a sufficient but not necessary condition for the measurement transition. The existence of an absorber, whether a human retinal cell or just a ground state atom,  is the necessary and sufficient condition.

Now, are all absorbers (indeed all quantum systems) inherently conscious? Does a photon really make a “choice” as to whether to go through a polarizer or not, as Heisenberg mused? Do quantum systems have some primitive form of volition? Freeman Dyson certainly thought so: “…mind is already inherent in every electron, and the processes of human consciousness differ only in degree but not in kind from the processes of choice between quantum states which we call “chance” when they are made by electrons.” (from Disturbing the Universe.) So this may be the case; but again, that’s a separate, and now well-defined, issue. Indeed, it can figure in providing a basis for free will (already explored here). But we no longer need to use consciousness as an ineffective band-aid for measurement in quantum theory. The study of consciousness deserves better.


The Arrow of Time from an Overlooked Physical Law


In this post, I’m going to disagree with the following statement by physicist Sean Carroll concerning the nature of time:

“The weird thing about the arrow of time is that it’s not to be found in the underlying laws of physics. It’s not there. So it’s a feature of the universe we see, but not a feature of the laws of the individual particles. So the arrow of time is built on top of whatever local laws of physics apply.”–Sean Carroll, https://www.wired.com/2010/02/what-is-time/

That is a common position, but it could very well be wrong. Specifically, what could be wrong with it is the claim that the arrow of time is “not to be found in the underlying laws of physics.” That claim comes from ignoring the possibility that there could be real, dynamical, irreversible collapse in quantum theory. If there is such collapse, that provides the missing link between physical theory and the phenomena we see that reflect the arrow of time.

First, it should be noted that collapse has been a formal part of standard quantum mechanics since the brilliant mathematician/physicist John von Neumann formalized the theory back in the 1920s. Von Neumann referred explicitly to collapse as a discontinuous, indeterministic process, and noted that it was irreversible. However, in recent decades, it has become fashionable to ignore collapse, which means to (explicitly or implicity) use an Everettian or “Many-Worlds” approach to quantum theory. The Everettian approach denies that collapse ever occurs, so in that interpretation, all the laws are time-reversible. This assumption underlies the usual negative conclusion (exemplified above by Carroll’s statement) about the existence of any physical law that could account for the irreversibility we see around us.

This evolution toward Everettianism has occurred for several reasons, probably chief among them the ad hoc nature of many of the specific models of collapse, which make changes to quantum theory. Alternatively, many physicists assume that collapse is just something that happens in our minds–that it corresponds to updating our own subjective information about the world as we advance through spacetime. But in that case, it is assumed that we somehow ‘move through’ the world, following an unexplained arrow of time. Clearly, if we are going to just help ourselves to an arrow of time in our ‘movement through the world,’ we are not explaining it.

Carroll’s assumption that the arrow of time has to be ‘built on top’ of laws that lack such an arrow involves appealing to notions of entropy increase– roughly, the idea that in a closed system, disorder always increases over time. But entropy increase, which is a time-asymmetric law, cannot itself be obtained from the allegedly underlying time-symmetric laws; that’s part of the ‘mystery’ of time’s arrow.  Moreover, trying to get time’s arrow from entropy considerations alone involves identifying the future solely with the direction of decreasing order in systems. This identification rules out identifying a future direction with processes of increasing order, which are commonplace (e.g., plant growth). Allowing exceptions for ordering process associated with living things on the basis that they are open systems doesn’t take into account that the universe as a whole is a closed system, and that such order-increasing processes take place, alongside other order-decreasing processes, within that closed system. Since entropy both increases and decreases all around us, and yet our experience is always future-directed, appealing to entropy increase is inadequate to the task of explaining time’s arrow.

Thus, the problem will not be properly solved unless physical laws really do have some irreversible component. But maybe they do: maybe we should not be neglecting collapse. And there is a model of collapse that does not involve changing the basic theory–it’s the Transactional Interpretation (TI). The transactional process corresponds precisely to Von Neumann’s intrinsically irreversible ‘measurement’ process. According to TI, ‘measurement’ is not about the consciousness of an observer (a very common misconception)–rather, it’s a real, physical process. That process is defined non-arbitrarily here,  here  and here.

Thus, we gain an irreversible step at a fundamental level of physical systems. For example, take a closed box of gas. With only time-symmetric (reversible) laws, it’s actually impossible to explain why entropy does not decrease in that box of gas. Appealing to ‘random thermal interactions’ doesn’t help, because the sort of ‘randomness’ one needs is time-asymmetric (this is explained very nicely by Price).

With collapse included, as in the transactional process, the thermal interactions between the gas molecules give rise to true randomness. Each such interaction consists of one or more photons being delivered from one gas molecule to another, in an irreversible process (the technical term is ‘non-unitary’). One molecule is the emitter and the other is the absorber, and the process of delivery of the photon(s) establishes the future direction. (For details on this account of spacetime emergence, see this paper.)

Interestingly, this picture also disagrees with the common assumption that ‘even in empty space, time and space still exist.’ (S. Carroll, same reference) However, Einstein himself also disagreed with that common assumption: he stated that ‘There is no such thing as an empty space, i.e. a space without field. Space-time does not claim existence on its own, but only as a structural quality of the field.’  (Einstein, Relativity and the Problem of Space.) The transactional account of spacetime emergence is completely consistent with Einstein’s observation. In that account, transactions establish, through exchanges of mass/energy,  the structure that we call ‘spacetime.’ Without those transfers of mass/energy, there is no spacetime, and therefore no arrow of time.