The problem that Block considers is how to define the mind in a non-circular way, which would mean avoiding mentalistic terms and concepts as part of the definition. (This is a notoriously difficult, perhaps intractable challenge.) What about behaviorism, i.e.diagnosing the presence of a mind in some entity by judging its behavior? This is what the Turing Test is supposed to accomplish. But can we describe the test without recourse to any mentalistic concepts, such as thinking? (Remember, thinking is what we want to define, so we cannot appeal to it as part of the definition, on pain of circularity.) So that's the problem that Block is grappling with here:

For example, one might specify that the judge be moderately knowledgeable about computers and good at thinking, or better, good at thinking about thinking. But including a specification of the mental qualities of the judge in the description of the test will ruin the test as a way of defining the concept of intelligence in non-mentalistic terms. — Ned Block

I'm not sure why you think so. The electron doesn't have to be transmitted at all. In fact, wherever the hole is located, we expect no electron to be transmitted most of the time. Any time the hole is at a site where the probability of finding the electron (as given by its wavefunction) is zero, then no transmission event will occur at all, for instance (i.e. you cannot slow the rate down to 0.001 Hz and get an event every 1 ms if the only available hole is sometimes inaccessible). — Kenosha Kid

In our example of a diffraction through slits the wavefunction is non-zero almost everywhere on the back screen, so that is not an issue. If an electron is ready to fire, and there is (in the edge case) just one hole that it can fill, then it will go there almost always, because where else would it go? Which means that the distribution over time will just be the distribution of holes popping up on the screen. We could put one slit, or two, or ten - doesn't matter, the distribution will be the same.

(Unless holes and/or emission events conspire to construct the distribution that we expect to see.)

Similarly if the probability of finding the electron at a given site is 0.2, you would expect an electron to transmit there when there is a hole there at most 20% of the time. — Kenosha Kid

Not if that's the only place where it can go, or one of the few places where it can go. Perhaps the emitter is picky and won't always transact with a hole just because it's available? So in your example if the only available hole is at a 20% probability spot, then 80% of the time the electron will wait out until another hole opens up (and then make another probabilistic decision). That would work, but where is the mechanism for this process?

In reality, the screen is more complex, and electrons will usually be able to squeeze in somewhere. But there should, as per Pauli, always be places it cannot squeeze, and that is neglected in ideal treatments. — Kenosha Kid

Yes, but in order to explain experiments where we see nice diffraction patterns, we must conclude that the number of holes available at any given time is not too few, or else we would be seeing something different (or we need to modify the theory).

You mean this?

Three of the fundamental equations of quantum physics are:
E=mc2,
w=P/mv,
and E=Pf,
where E=energy, m=mass, c=the velocity of light, w=wavelength, f=frequency, v=velocity, and P=Planck’s constant.

If the first two equations are solved for mass, followed by substituting and canceling such that the absolute minimum of variables remain, the simplest synthetic formulation is v=fw. This implies that all matter is in motion, and the structure of this fluxing matter takes the intrinsic form of a wave. It appears that since mass can be vacated from the hybrid expression in favor of a more essential form, namely a wave, the structurality we associate with mass, namely three dimensional particularity, is an epiphenomenon. Then we must inquire as to the sense in which this is true. — Enrique

You seem to be groping around the idea that massive objects exhibit irreducibly quantum behavior, which is expressed in the equation for the De Broglie wavelength. Since massive objects exhibit wave-like behavior, each of them has a characteristic wavelength associated with it. For example, when a basketball falls through a hoop, it undergoes diffraction, just like when light shines through a pinhole - an immeasurably tiny bit of diffraction, which nonetheless we can theoretically estimate via its de Broglie wavelength. This isn't about matter being in motion - that is a triviality. Since motion is relative, everything is or is not in motion, depending on the reference frame. Rather, this is about one specific manifestation of quantum behavior of matter, which you overthink at your peril absent the understanding of its full context.

As for the rest... I couldn't get much further than the next paragraph, which quickly devolves into a word salad. This is not a theory in any meaningful sense.

Not *only*: the wavefunction of the emitted electron still natters; my point was rather that it can't be the *only* thing that matters.

In TQM itself, the probability of a transaction causing absorption at (r, t) is the amplitude of the retarded wavefunction arriving at (r, t) times the amplitude of the advanced wave travelling backward from (r, t). So it depends on the probability amplitude of *both* waves. — Kenosha Kid

Well, the confirmation wave is just an echo of the offer wave: its amplitude is proportional to the amplitude of the offer wave at the would-be absorber. So the information carried back by confirmation waves is redundant, as far as the system as a whole is concerned - it's just a mechanism for establishing a transaction in accordance with the Born rule.

In your example of a screen that has only one absorption site at any one time, only this site can backwards-emit a hole wave. In the language of TQM, only this wave can handshake with the retarded wave, since the amplitude coming from all other sites is everywhere zero.

However, that single hole will move around the screen and, on average, should be smeared out such that the probability distribution we see forming is given only by the retarded wave. — Kenosha Kid

If the hole moves around independently of the impacting wave, while emissions are a Markov process, i.e. a transaction is established whenever a hole is available (as you explain below), with no "knowledge" of what comes before or after, then the resulting distribution of impacts will be independent of the impacting wave. It will only depend on the entropic movement of the hole - most likely just a uniform distribution.

Some dependence on the wavefunction will manifest when multiple holes are available at the same time, but unless there are a whole lot of them (rather than "not many"), the distribution will be blurred.

As someone with nominalist inclinations, I still find this charming, right down to the note of pragmatism: — Srap Tasmaner

Yes, this sounds like where I am at as far as ontology is concerned, though I could never put it as gracefully as Grice does here. I'll have to dig up this paper.

That's so ironic.... That's precisely how I feel about nominalists. — Mapping the Medium

Ooh, burn!

Just curious, what does "nominalist" even mean to you? You don't seem to use it in its usual meaning, but more like "motherfucker."

Is it just me or are Peirce fans rather a cultish bunch? I have yet to meet anyone with a moderate and critical interest in Peirce. It seems like anyone who talks about Peirce more than in passing is almost religiously devoted to him.

That this doesn't hold true is precisely my point. While an individual transmission may depend on the precise microstate of the screen, the screen explores these microstates continuously. A statistical number of transmission events will take place over a period of time, during which one will have a statistical spread across the precise microstates explored during that time, a spread which looks like the probability of finding a given electron at a given position depends principally on the wavefunction. — Kenosha Kid

Let's take an extreme example:

1. The emitter (of electrons, photons, ...) is under experimental control, so that for instance we can ensure that a particle is emitted every millisecond.

2. The availability of receptive absorbers is so constrained by present and future boundary conditions that at any point of time at most one site is available.

Right away, if at the time when we want to make emission happen there are no available absorbers, then we have a problem: some assumption has to give. But even if an absorber is available, the cumulative distribution of impacts will be defined only by the distribution of the available absorbers on the screen over time. And at the same time, in order for the Born rule to hold, that distribution has to match the impacting wavefunction - whatever it happens to be. If we can contrive to emit a particle that hits the screen at times (t₁, t₂, ...), the screen had better supply us absorbers at such locations r_i that (r₁, r₂, ...) form the distribution that we expect to see.

So how can this happen (or can it happen)?

A. (1) and (2) hold, which means that the screen and the universe in its future lightcone have to contrive to match the impacting wavefunction. While no individual absorber is constrained to be in a fixed position at a fixed time, there is a constraint over time on all such absorbers, which is a function of the impacting wavefunction, whatever it happens to be.

B. (2) doesn't quite hold: instead of just one absorber at a time, we have "not many" absorbers. This relaxes the constraint on the screen, but does not completely eliminate it. Unless there is such a constraint, the actual distribution of impacts will inevitably be distorted.

C. (1) does not quite hold: we cannot make emissions happen at will (can we?) This distributes the constraint of producing the right cumulative distribution between the emitter and the screen or shifts it entirely to the emitter, so that now it is the emitter's responsibility to be aware of the state of the screen (and the rest of the universe in the future lightcone) and fire particles under the constraint of producing the right distribution.

The cancellation depends on both waves being advanced waves, so it's not purely terminological. (Advanced waves cannot cancel retarded waves in Cramer's formulation.) — Kenosha Kid

Why not? If I understood it correctly, the reflected wave is out of phase with the advanced wave, so it must cancel it. That the time direction is reversed means that the cancellation occurs everywhere at once, so that to an observer it is as if neither wave ever existed. Only the advanced wave back towards the BB is cancelled; the retarded wave from the emitter is out of phase with the advanced wave, which means that it is in phase with the reflected wave.

Cramer’s proposal cannot work for EM waves, simply because the early universe was not transparent to EM radiation — Darko B

He addresses this concern in the paper, but this physics is way above my pay grade.

Getting back to this topic (sorry, this is tough slog for the old cat-brain):

Clearly then the true probability of transmission from cathode to any given site A-E is not identical to the absolute square of the wavefunction (denoted by the blue rays coming from the cathode), but also on whether each site has an electron in it or not. — Kenosha Kid

So the bolded part is what I am having difficulty with. We do, of course, observe that the cumulative distribution of impacts on the back screen is in line with the square of the wavefunction from the emitter. If emission occurs whenever, while the distribution of available absorbers on the screen is constrained by external factors, then we won't recover the expected distribution. (In the edge case where at most one site is available at any time, the distribution won't even have any dependence on the impacting wave!)

The only way to recover the expected distribution that depends only on the impacting wavefunction is if the timing of successive emissions is coordinated so as to compensate for the constraint from boundary conditions and produce an undistorted distribution over time. But I don't see how such compensatory mechanism is being realized.

Cramer claims to have mapped the above arrow of time to the cosmological arrow in the paper here:

Another paper by Cramer (Foundations of Physics, 1973) specifically treating the arrow of time: http://faculty.washington.edu/jcramer/TI/The_Arrow_of_EM_Time.pdf — Kenosha Kid


However the more I read it the less compelling I find it. He actually talks about advanced waves going forward in time, which is contrary to what an advanced wave is. — Kenosha Kid

Yes, he says the entire four-vector is reflected at the Big Bang boundary, i.e. time direction of the advanced wave is flipped, but still insists that the reflected wave is an advanced wave. But other than terminology, do you see any issues with his proposal?

But what did I say that was false? lay it out concisely: what is the problem? — jamalrob

You said stuff that a belligerent moron with no reading comprehension might interpret as you endorsing Putin. Shame on you, sir!

Well, have to say that some progress has happened. — ssu

Yes, you are right, if you look at the numbers, the good old times were pretty terrible compared to now. State and even some non-state actors have become more shy about committing atrocities, although often that just means that they lie about it (not caring very much about whether anyone believes their lies).

But the most immediately painful scars are from the 1990s. Nobody wants to go back to that, and that's partly why Putin has been popular. Pro- and anti-Putin often agree that he did what had to be done in his first years in power. Anti-Putin people differ now in thinking, come on, that's enough, time to go. — jamalrob

Some of that fear of the "chaotic 90s," as well as the nostalgia for the good old days of the Soviet rule has been helped along by state propaganda. So is the idea of Putin riding in to save the day in 1999. A lot of the economic recovery during 2000s can be quite simply accounted by the booming oil prices and the accompanying rise in Russia's oil and gas production.

I suppose piano teachers, especially, are always aware of the issue when engaging a young child. Because it may be the critical stage of development. But also because a keyboard is discussed as a diagram of the pitch dimension? — bongo fury

It was violin in my case.

Why intervals? Just to help find the notes? Or is it the other way round? — bongo fury

Intervals have a distinctive sound to them that has to do with the size of the interval rather than the pitch (that is with modern equal temperament). Once you learn what each interval is called (minor third, perfect fifth, etc.), you can learn to identify them by hearing, regardless of the pitch. Same with standard three-note chords. Such basic music theory and ear training are part of a classical musician's training.

I wouldn't overstate the importance of pitch recognition. I don't know if it's much more than a minor convenience for a musician or a party trick. There are any number of very fine musicians who didn't have a perfect pitch as an innate ability. Also, identifying the pitch of a note is not the only and not the most important ear skill. For example, while I can (could) easily identify individual notes or melodic lines, I am not that good at harmony - most professional musicians are probably much better at it than me. Another sort of discrimination is the purity of the tone: I may be able to identify a tone that is "close enough" to a standard pitch, but a more sensitive ear can pick up finer differences. An experienced conductor can instantly spot a slightly off-key note somewhere in a hundred-strong orchestra or choir.

The idea that nations can lose their will to fight and can be demoralized by bombing their cities was the theory of Douhet. The opposite appears to be the reality with conventional bombing. Yet politicians are sensitive to these kind of issues and many times the response if more about politics than military necessity. — ssu

Brutalizing civilian population on enemy-controlled territory still seems to be the standard tactic in modern conflicts, from soldiers and rebels slaughtering villagers in sub-Saharan Africa, to Russian special forces burning villages in Chechnya, to government forces bombing tenement buildings, markets and hospitals in Syria and Yemen. The only difference now is that perpetrators routinely deny their war crimes. The times during WWII and before were, in a way, more honest, but hardly more brutal than they are now.

In both cases, there's no purely rational decision. — Michael

Well, how would you define a rational decision? Any reasoned decision is anchored in values, and values as such are not rational (I don't think). I would say that as long as a decision is explicitly aimed at achieving that which you value, then it is a rational decision. If you like to gamble for the highest potential reward, then it is rational for you to play two different lotteries. If you are risk-averse, then it is rational to play one.

(As a useful oversight, the expected return is equal to the bet, so as an additional question, is there a reason to play at all?) — Michael

In commercial lotteries the expected return is much less than the bet, so if your utility function is just the expected return, then most lotteries are losers. And yet people buy lottery tickets. Which means that utility for those people is more than just the expected return.

So the answer to your question:

So, given that the expected return is the same, is there a reason to prefer one way over the other? — Michael

Depends.

I had* an absolute pitch as a kid, before any musical training. I don't remember how my first music teacher diagnosed it (since of course I didn't know notes and couldn't yet play any instrument at five), but there must be some standard tests. Pretty soon, once I learned to associate notes to sounds, the notes would just pop into my head when I heard them, sort of like how you recognize letters when you see them on a page.

My sister, who also started learning to play early and, unlike me, went on to train as a professional musician, did not have an absolute pitch. She practiced much more than I did, and she acquired some degree of proficiency in associating notes to sounds, but not to the degree that I had always had. When she was practicing for a college entrance exam, she even had me drill her on identifying notes, intervals and chords. She could recognize notes pretty well, but only after hearing a reference note or chord. She never acquired an absolute pitch.

* I used the past tense here, because as I was approaching middle age my hearing went "out of tune." (This is not uncommon.) This actually makes a difference to how I hear music. It's hard to describe the feeling; it is somewhat disorienting. At some point I realized that my inner pitch became very close to the so-called Baroque pitch, which is almost half a tone lower than the modern pitch. I was listening to a period instrument recording - and suddenly everything fell into place, the notes were ringing out in my head like they used to. Even knowing this, it's not easy for me to gauge the modern pitch. Somehow the shift makes me uncertain about my bearings.

A musical/literary anecdote: The Russian poet (and future Nobel laureate) Boris Pasternak was a gifted musician in his youth. He wanted to be a composer, but he agonized over his lack of a perfect pitch, which he thought was a major handicap. One day he got to meet his idol Scriabin and played some of his compositions for him. Afterwards, while they talked, the famous composer went to the piano and played back some of Pasternak's music from memory... but to the latter's astonishment he played it in the wrong key! It was then, Pasternak later recalled, that he realized that Scriabin didn't possess the vaunted perfect pitch either.

Exceptionally, that is, such a pattern as Three Blind Mice might be first appreciated as properly obtaining only in a particular key (probably starting at a particular place on a particular instrument), and any transpositions of it counted only and specifically (by both parent and infant) as such: as transpositions of the original pattern. — bongo fury

There are, I think, different types of musical memory. I may accurately recall some music shortly after hearing it, or often a day later, together with its original pitch. But in time I may retain the memory of the melody, while forgetting the original pitch. If then I recall or look up the key or the first note, then I can reconstruct what the original music must have sounded like in my head. This is not unlike hearing someone talk: you may retain the words longer than the way they sounded like when you heard them.

God is a transgendered Cat? — Book273

Huh?

The answer is obvious I think.

Heh. The normally reserved New York Times has dropped all pretense of impartiality:

Trump lies in the White House briefing room, and the networks pull the plug.

President Trump broke a two-day silence with reporters to deliver a brief statement filled with lies about the election process as workers in a handful of states continue to tabulate vote tallies in the presidential race. — NYT

I browse NYT regularly (usually just morning briefing Europe), and I've watched with mixed feelings their evolution from the first time when they dropped the L-bomb (there was an article from an editor at that time, explaining why they thought it was appropriate to say that Trump lied, as opposed to using a more neutral word) to this.

My early prediction (from before the pandemic) was that Trump would win reelection with a bigger margin (winning the popular vote as well). The sad thing is that in all likelihood, the main reason he isn't doing so well now is that the pandemic happened at the worst possible time for him. And what is hurting him is not his administration's incompetent and erratic handling of the response, but the fact that when times are hard - and they would have been hard even with the best possible response, for a number of reasons - people tend to allocate some blame to those at the top, regardless of how much or how little they are actually responsible. Any leader would have lost popularity after nine months of misery and at the height of the second (or is it third?) wave of the pandemic.

Yeah, we don't even know all that much about how animal eyes work - color resolution, etc. We have some idea, but there is considerable uncertainty there. As for vision at the level of cognition, my guess is that we know much less than that. And what we can learn would be expressed in the language of neuroscience or psychology, which isn't the same as conveying "what it feels like."

See The World Through The Eyes Of A Cat

Yes, we are well aware of that. Even ordinary photo-video media (film, digital sensors) don't have the same light sensitivities as the human eye, and that has long been known and accounted for in various ways. But while in a consumer photo camera, for example, you want maximum fidelity to human perception*, when it comes to scientific imaging we have been sensing far outside the human range, and for a long time. Radio telescopes, for example, have been around since 1930s (says Wiki). On Earth we also use a wide spectrum of EM radiation, magnetic fields, ultrasound, electron beams, gravity sensors and other creative sensing techniques.

* Fun fact: digital cameras include an infrared filter, without which they would be picking up IR light. If you have an old digital camera that you aren't afraid to break, you can try and remove it yourself - and presto, you can now take pictures in the infrared spectrum!

I am not sure. The motivation for the Wheeler-Feynman absorber theory is to have a time-symmetric formulation of classical electrodynamics, right? Both Type I and Type II absorptions are symmetric, but I don't see why you have to have both, and not just Type I. Type I is just an interpretation of classical electrodynamics, since it is formally equivalent to it. Type II constitutes a net new addition to the theory, for which we have no evidence.

Of course, if it could be tested and confirmed, that would be quite remarkable. Cramer says (referring to earlier analyses) that if both types occur, one of them is expected to dominate - presumably, Type I in our case. But that still leaves a possibility of some Type II absorptions. Do you think it's likely that they would have gone unobserved/unnoticed all this time? How difficult would this be to test?

I was just rereading part of the paper on type II emission and absorption events, which are interesting. If we take the emitter to be atom 1, the absorber to be atom 2, and the emission to be a photon, from the lab frame it appears as a photon (its own antiparticle) from the origin is absorbed by atom 1 (the emitter) and then, seemingly unrelatedly, atom 2 emits a photon of the same energy, which continues forever.

If the distance between the two atoms is L, the time between perceived absorption and emission (actually emission and absorption) will be L/c. So if type II is possible, it ought to be detectable experimentally in principle, though in practice it would be hard if the phenomenon is limited to CMB radiation (assuming that's all that could constitute a photon from the origin).

What's more interesting is the idea that causal relationships between events can be apparently unmediated in principle. — Kenosha Kid

I wonder why he thinks that Type II emission is equally possible as Type I. Type I is an interpretation of a well-studied phenomenon (emission/absorption of EM radiation), while it takes work to explain away Type II. What's the rationale in proposing it? Just a general preference for symmetry?

Well, Sam put a good deal of work into his posts, and he actually made philosophical points, not just jee-whiz, isn't it special. He was a crackpot and his arguments were crap, but that's for others to decide.

In TI the electron is still essentially its wavefunction, right until its inglorious end. So it will go through both slits, interact with itself, etc. The twist is that there are two interacting wavefunctions - retarded and advanced. You can go with Feynman path integral formulation for the wavefunctions (as I think would be @Kenosha Kid's choice), but that is detachable from TI itself.

It being a wave (waves) takes care of some well-known interpretational challenges that trade on the wave-particle ambiguity, like delayed choice and quantum eraser. That said, some challenges have also been proposed that are specific to TI, such as the quantum liar experiment.

there are a number of alternative relativistically invariant wave equations, at least one of which is first order in time — SophistiCat

But also first order in space, I think? So the four solutions (advanced spin up, advanced spin down, retarded spin up, retarded spin down) reduce to two (advanced and retarded). — Kenosha Kid

He mentions a "relativistic Schrodinger equation," which has has a (P² + m²)^1/2 term.

Sure, but scattering also obeys the Pauli exclusion principle, so there must be two holes: one for the scattering electron to go to, and one for the scattered electron to go to (see the Feynman diagram in the OP). And those scattered electrons can scatter again, each requiring two holes, and so on and so forth. So it's a proliferation of backwards hole emission and transmission events. — Kenosha Kid

Does the incoming electron always scatter on another electron? If it's a solid that it interacts with, wouldn't it be something more complicated? Anyway, let's run with the assumption that in any type of interaction the electron is constrained by the requirement of having a (potentially infinite) chain of suitable boundary conditions.

No, because the probability distribution of the incident electron will still multiply the probability distribution of acceptor sites. — Kenosha Kid

Not if there is only one available site - in this case the electron wavefunction becomes irrelevant. The electron wavefunction removes at most a measure-zero amount of potential interaction sites, so without loss of generality we can assume that for any incoming electron, every point on the screen is available before we consider the conditions at the screen. But if the conditions at the screen are such that only one site is available, then that is what will dictate the actual distribution of impacts, not the electron wavefunction.

In case of "not many" available sites, the impacting distribution will factor in, but it will be smeared.

some relativistic formulations of the wavefunction equation have two solutions: w and its complex conjugate w* — SophistiCat

All, I believe. — Kenosha Kid

I was hedging because in his 1980 Phys. Rev. D paper Cramer writes that for particles with spin other than 1/2, e.g. bosons, there are a number of alternative relativistically invariant wave equations, at least one of which is first order in time. I don't think he considered the full QFT formulation though.

The advanced wave must be similarly causal but in reverse. For an advanced wave to be emitted from a particular point on the screen (describing an electron hole in reverse), that point must be capable of doing so. Otherwise the retarded wavefunction depiction of the electron leaving the cathode is unjustified in the first place. — Kenosha Kid

Are there really any absolutely forbidden points of interaction? Instead of being absorbed, can't the electron scatter instead?

In the case of both microstate exploration and decoherence, the precise state changes constantly. An electron on the screen which might forbid an incident electron at time t might not be present at time t'. A particular configuration of scatterers that would destroy the wavefunction at time t might permit it at time t'.

The signature pattern of the double slit experiment is not one event but many thousands. What we see then is not just the value of the probability density of the electron, but also the statistical behaviour of the macroscopic screen. Over a statistical number of events, the pattern must be independent of changes in the precise microstate of the screen. — Kenosha Kid

So let's consider a limiting case where exactly one spot on the screen is available for interaction at any one time - an advance electron hole, as it were. This is what you hypothesize might indeed be the case, right? We can fairly assume that such points are uniformly distributed over the surface of the screen*. If the availability of electron holes imposes an absolute constraint on where an interaction can occur, then instead of the interference pattern we should see just that - a uniform distribution.

* Or in any case, we can't expect their distribution to coincide with the amplitude of the incident wave.

I think it's more economical than parallel universes. — Kenosha Kid

Well, if I understand correctly, the Everett interpretation is characterized more by what it doesn't do - arbitrarily impose a collapse - than by what it does, so in a way it's hard to be more economical than that (although it does ditch those advanced solutions. Hm... could you combine the two?...) But I didn't mean to imply that parsimony and fidelity to the formalism are the only or the most important criteria in evaluating philosophical interpretations. I am rather ambivalent on that point.

So I went back to Cramer's papers from 1980s onward in an attempt to gain a better understanding of the transactional interpretation. I think I managed to unconfuse myself a bit regarding the "orthodox" TI, but I am still not sure about your take on it.

The core of the theory is an emission-absorption process, such as when two atoms exchange energy or (as in your presentation) an electron is emitted and later absorbed by a solid. (I think scattering is handled similarly, but I haven't looked into it yet. There is also an issue of weakly-absorbed particles, such as neutrinos, which may not have a future boundary; I know that Cramer has looked into this, but I haven't.)

The process is initiated by a "transaction" between the emitter and the absorber, which is described by the following reversible pseudo-time sequence:

• The emitter produces two half-amplitude waves: a retarded wave going in the forward time direction and an advanced wave going in the backwards time direction (with a negative energy energy eigenvalues and phase-shifted by 180 degrees).
• The absorber is "stimulated" by the retarded wave from the emitter (offer wave) and also produces a pair of half-amplitude waves going in opposite time directions. The advanced wave from the absorber (confirmation wave) reaches back in time towards the emitter.
• When there are multiple potential absorbers, they all produce confirmation waves with amplitudes proportional to the amplitude of the offer wave. The absorber is selected randomly, with the probability of selection weighted by the square of the amplitude - this is where the Born rule comes into play.
• Once the emitter and the absorber "handshake" (which is sometimes described by another pseudo-process, which I haven't investigated), the "tails" of the wavefunctions going back in time from the emitter and forward in time from the absorber cancel out, as are the imaginary parts of the waves between them, leaving only the superposed real parts of the offer and confirmation waves. To any observer this will look as if a wave traveled from the emitter to the absorber.

(I hope I got this right.)

The above is offered as an interpretation of the standard quantum mechanics formalism, rather than some additional physics. The steps do not describe a causal time sequence of events - they merely serve a pedagogical purpose.

The rationale for the interpretation comes from the fact that, as KK mentioned, some relativistic formulations of the wavefunction equation have two solutions: w and its complex conjugate w*. But complex conjugation is equivalent to time reversal (although it also implies negative frequency, energy and charge) - hence the advanced wave that is produced alongside the retarded wave in TI. Plus the Born rule, etc. - the conjugate of the wavefunction is ubiquitous in the formalism.

It is interesting that both the TI and the Everett MWI start from similar philosophical positions. Both are realist about the wavefunction (in contrast to Copenhagen). Both are offered as minimalistic interpretations that do nothing more than take the math seriously (as Sean Carroll, an Everettian, puts it). "From one point of view, the transactional interpretation is so apparent in the Schrodinger-Dirac form of the quantum-mechanical formalism..., that one might fairly ask why this obvious interpretation of the formalism had not been made previously" (Cramer). But they still end up in very different places. To me it seems like TI goes further out on a limb than MWI. I am uncomfortable about the pseudo-causal narrative of the "transaction." But perhaps the more profound aspects of the interpretation escape me.

This bit I don't understand though:

Because the electron's birth and death are the true boundary conditions of its wavefunction! And here we turn to relativity. The relativistic wavefunction is of the form [E−V]2=[p−A]2+m2. This puts time and space on equal footing (both energy and momentum are squared), requiring knowledge of the particle at two times, not just one. — Kenosha Kid

Whether it's the non-relativistic Schrodinger equation (which has only a retarded solution) or a suitable relativistic equation (which has both), the equation alone does not determine where and how the absorption/measurement will happen - hence the "measurement problem." I am not sure what point is being made here specifically about the relativistic equation.

(The Schrodinger equation can be produced as a non-relativistic limit of a more general relativistic formulation. How then do two solutions reduce to one? Turns out that two versions of the Schrodinger equation are equally valid reductions: the other one has only an advanced solution.)


Now, as for the "not many worlds" interpretation:

There is no guarantee here that this will eventually reduce the number of intersections with the screen to 1. But we are a long way from the original Copenhagen picture of an electron that might be found anywhere. I expect that, if we could solve the many-body Dirac equation for the universe (well, it would have to be some cosmologically-consistent generalisation of it), it probably would resolve to 1 intersection. — Kenosha Kid

I still don't see how this can be. Boundary conditions are, by definition, local. And yet when we do experiments like quantum interference, we find that the measurements depend mainly on the incident wave. Why aren't results confounded by such strong dependence on the boundary conditions?

Hey, just to let you know, I want to think on this some more, don't want to reply just for the sake of saying something.

All I can see from your quotes is that Mary Midgley is dissing someone you don't like. If that is what turns you agush... meh. May as well listen to a rap battle or something.

Genes cannot be selfish or unselfish, any more than atoms can be jealous,
elephants abstract or biscuits teleological.

I mean, this is just stupid. I trust there is more to what she says, but you are not selling it well.

U.S. intelligence agencies warned the White House last year that President Trump’s personal lawyer Rudolph W. Giuliani was the target of an influence operation by Russian intelligence, according to four former officials familiar with the matter.

The warnings were based on multiple sources, including intercepted communications, that showed Giuliani was interacting with people tied to Russian intelligence during a December 2019 trip to Ukraine, where he was gathering information that he thought would expose corrupt acts by former vice president Joe Biden and his son Hunter.

The information that Giuliani sought in Ukraine is similar to what is contained in emails and other correspondence published this week by the New York Post, which the paper said came from the laptop of Hunter Biden and were provided by Giuliani and Stephen K. Bannon, Trump’s former top political adviser at the White House. — WaPo

From the overlap integral of the retarded wavefunction with the advanced wavefunction:

In transactional QM, this is the very meaning of the Born rule. — Kenosha Kid

But this only gives the "real paths" of the electron once the "boundary condition" on the other end is fixed, i.e. once the measurement already happened at the back screen. This doesn't explain any actual data though: we have no independent knowledge of those "real paths" besides what the interpretation tells us. What we have from experimental setup and observation are just the boundary conditions, the origins of the retarded and the advanced wavefunctions. And while we fix the former by our setup, all we know about the latter in advance is:

When a particle moves from event (r,t) to (r',t'), it still does so by every possible path (Feynman's sum over histories). If you sum up every possible r' at t' and normalise, you recover the wavefunction at t'. — Kenosha Kid

which is no more than what vanilla QM tells us and doesn't explain the really interesting bit, i.e. the measurement problem. And isn't that what we really want from an interpretation?

So what mechanism fixes the forward boundary condition?

Ah, I see. This is deeper than I'd realised. Simply multiply whatever complex number by whatever physical unit: we never see that. I see I have 10 fingers and that I'm 5.917 feet tall, but I have never weighed (12 + 2i) stone. — Kenosha Kid

Well, of course, if you take something that is usually represented by a scalar, such as height or weight, then a real number will be optimal as a mathematical representation. But take something like stress, for example, and you'll want a tensor or a vector at the least. (Although if you really set your mind to it, you can map a quantity of any dimensionality to any other dimension. You can map 6-tuples to scalars and back - it'd just be horribly impractical.)

I'm getting confused now between ontologically real and real as in has no imaginary component. — Kenosha Kid

Yeah, I suspected as much.

The OP holds that the complex wavefunction is an ontic description -- or fair approximation to such -- of how particles propagate through space and time as we represent them. How we describe the relationship between time and space is intrinsically complex, just from straight relativistic vector calculus, which happens to be the language quantum field theory is written in. There are other languages for describing relativity that can do away with the imaginary number and it may well be that in future we can generalise QFT in a similar way; such an endeavour would be part of a general relativistic quantum mechanics. So I don't hold the complex wavefunction to be an ontic description of the particle itself, rather it encodes the ontology of the wavefunction in our spacetime representations accurately, e.g. encodes information vital for doing the physics. — Kenosha Kid

Fair enough.

As I read your reply I realized that I didn't really understand the OP :confused: So let me try another question to see if that helps a bit: How does your (transactional?) interpretation recover the Born rule? How do you get the interference stripes in the double slit experiment? Unless I misunderstood again, it seems like you were saying that real-world constraints (availability of holes, etc.) should cut down on indeterminism and perhaps completely eliminate it in the limit. But then we have to believe that these constraints just happen to conspire to produce results consistent with the probability distribution?

But these aren't physical either. It is simply that complex exponentials are much easier to manipulate than individual sines and cosines. — Kenosha Kid

Well, exactly. You can reproduce all complex-valued math without recourse to imaginary numbers or complex exponentials - it would just be more work. But then I don't understand why you insist that

But no complex quantity can be physical in itself, i.e. we can't observe it in nature. — Kenosha Kid

Complex quantities are no more and no less physical than real quantities, tensors, vectors, and whatnot. They are all mathematical objects.

That's actually not an uncontroversial statement. The wavefunction is frequently referred to epistemologically as the total of our knowledge about a system. The OP basically states that it encoded more ignorance than knowledge. — Kenosha Kid

he wavefunction can be written as a real function multiplied by a complex phase defined everywhere (this is trivial: a complex number has magnitude and phase). The phase is important for interference effects, but makes no difference when it comes to observables. The former is why I believe in an ontic wavefunction, and the latter is why the wavefunction might be considered epistemic. — Kenosha Kid

Sorry, you seem to be making a distinction without a difference here. Both the amplitude and the phase are essential for encoding our knowledge about the system. So if that makes the wavefunction real in a broad sense (which is fine by me), then the whole of it has to be real, not just the amplitude.

You are overthinking it. I haven't looked at the video, but the wiki on Penrose tiling explains the sense in which the pattern doesn't repeat: it just means that the entire tiling doesn't possess translational symmetry. If you shift it by some amount in some direction, you can never get the same picture - unlike patterns printed on fabrics, wallpapers, etc. The connection with numbers like pi is that those numbers are irrational, which means that their decimal expansion also does not include an infinite periodic part (semi-infinite in this case).

If you can identify a repeating part in a pattern, you can just do sort of a variable substitution, designating that repeating part as one super-tile. Then the entire tiling is simply that one super-tile repeated infinitely in all directions, like squares on a chessboard or hexagons in a honeycomb. With an aperiodic tiling you cannot do that.

I hope to provide an argument that utilizes the prime principle of confirmation to show that objective beauty provides evidence in favor of the hypothesis of theism over that of atheism. — Daniel Ramli

Collin's so-called prime principle of confirmation notoriously provides spurious support. Collins tries to repair it with an injunction against ad hoc hypotheses. Whether or not that is a successful strategy for Collin's argument, your argument doesn't even attempt it: your God hypothesis is blatantly ad hoc, i.e. it presupposes everything you need to make your probability as high as you want it to be.