I understand your post in and if itself, but have no idea how it relates to order being good and chaos being evil. A mass grave of Jewish corpses in a concentration camp is highly ordered compared with a cemetery, yet is a symbol of utmost evil.

If you want to distance yourself from Hitler, you don't go for a toithbrush moustache. Why muddy the already muddy waters? — Agent Smith

Oops.

OK

Well it's still all to play for, but by my reckoning, if it diffracts like a wave and it interferes like a wave, it's a wave. — Kenosha Kid

Of course. The physicist wants his quarks and leptons (or subs within them, to which muon g2 anomaly seems to hint) to be real. What's thought real or not varies and there is, especially nowadays, no consensus, not even for the fundamental, what the right picture is.

Yes. If you reverse basic processes, you can't tell if time goes forward or backward. I don't think though that the absorption of a photon is the reversed process of absorption. The absorption involves a different photon state as the emitted photon. So one can see the difference. Or not?
What about the evolution of the wave function? Reversing motion will still produce collapse. Collapse is insensitive to time reversal. Still, if you reverse the movie of a collapse, a superposition magically appears.

Human behavior, if you'll take the time to notice, breaks this easiest route rule - we do things in very inefficient ways, most of the times failing to take the shortest route between beginning (of a project) and its end. In essence we violate the Principle of Least Action.

Since deterministic systems have to adhere to the Principle of Least Action and humans consistently violate this principle, is this free will? — Agent Smith

I'd say the delay in finishing the project is not due to not taking the shortest route most directly and efficiently. It is because the man, the person, the mind, is taking care of more than one project at any given time. These projects compete for the attention of the individual. Much like as if there were several rivers, and one had to run between all of them, lifting gates to let the flow go, and then putting the gate back before running over to another river to lift ITS gate.

The person must prioratize his projects. Random events also thwart him. I think his responses to the priority-building and attending to unplanned activities necessary to attend to will make him get delayed in the project of the main, but it's not due to lack of efficiency, but due to lack of available attention.

My explanation does not exclude or include postively the determnistic approach or else the religious one. My explanation just shows you why the river gets to flow uninterruptedly, and why the project is still under deterministic build, despite the stoppages on the work of the protject.

Since deterministic systems have to adhere to the Principle of Least Action and humans consistently violate this principle, is this free will? — Agent Smith

This thought experiment here is ill conceived because causality is NOT derived from physics. It is presupposed by physics. The principle of least action is just a variant of the principle of sufficient cause, which is apodictic.

If you want to go after freedom, you have to look at how the things work: long story short, we live most of our lives unfree, that is, bound to the processes of living that are part of our existence's structure: the working, cooking, driving, making plans, and so on--these are not "freely" done. They are done without any second order of thought at all, robotically, if you will, automatically, no more free than my finger hitting the right key while typing. Invisibly done, as an act of instinct: it occurs independently of a free will, even if there is such a thing.
But stop typing, because there is a disfunction, and now you have to attend to this, and now you are "free" of the automatic process. Now pull back from the entire living process of rote activities, allow none to possess your attention. Now you are in a rare state of mind, open, and when a thought does occur, you dismiss it, for thoughts are agencies of control.
You are free, are you not?

The physicist wants his quarks and leptons (or subs within them, to which muon g2 anomaly seems to hint) to be real. What's thought real or not varies and there is, especially nowadays, no consensus, not even for the fundamental, what the right picture is. — Raymond

I'll agree that there are hierarchies of ontology. I don't _believe_ in quarks the way I believe in houses. But it's not just a case of wanting. By that logic, it's equally sensible that something that diffracts and interferes isn't a way, which is linguistically incoherent.

I don't think though that the absorption of a photon is the reversed process of absorption. The absorption involves a different photon state as the emitted photon. So one can see the difference. Or not? — Raymond

Absorption backward is emission, and vice versa.

What about the evolution of the wave function? Reversing motion will still produce collapse. Collapse is insensitive to time reversal. Still, if you reverse the movie of a collapse, a superposition magically appears. — Raymond

Collapse is irreversible, for sure. But probably not real. (Fight! Fight! Fight!) Another aspect is the thermodynamics of the evolution of the wavefunction: its dispersion. If you measure a particle, it has a very localised wavefunction. As time progresses, it spreads out. It never does the opposite.

I'll agree that there are hierarchies of ontology. I don't _believe_ in quarks the way I believe in houses. But it's not just a case of wanting. — Kenosha Kid

I can always say that you see quarks because you only belive in them (personally I believe in two even smaller particles and find the believe in elementary quarks and leptons contrived but justified). The believe system of sciences is based on the existence of one objective reality to be explored by us interacting and theorizing. The reality is usually defended by stating that it's a succesful approach. Throw your notion of success and of one reality only overboard and quarks dissappear from the scene. Usually it is replied then that quarks still exist but you just close your eyes to them by. Here I disagree. That's the same as saying God exists no matter if you believe or not. Of course, for people believing in quarks (like me, but not as basic entities), quarks are real. Though the are pretty far removed from daily existence and they show themselves under pretty strict experimental conditions. When quarks were introduced in the sixties it took another 10 years to prove their existence and Feynman didn't believe in them, though he believed in partons. The pre-quark world of hadrons and mesons was completely different from the world of quarks, with a different experimental practice.

Another aspect is the thermodynamics of the evolution of the wavefunction: its dispersion. If you measure a particle, it has a very localised wavefunction. As time progresses, it spreads out. It never does the opposite.
3hReplyOptions — Kenosha Kid

But what spreads out? If it spreads out it can collapse.

By that logic, it's equally sensible that something that diffracts and interferes isn't a way, which is linguistically incoherent. — Kenosha Kid

I'm not sure I understand. Something isn't a way? And why is it a bad thing that something is linguistically incoherent? I can say that I see, interact, with quarks, make triplets and duals of them collide and still say they are not real, however incoherent that might be. The incoherency stems from your concept of reality. If you base that on being able to grab it, then it's incoherent, if not, then it's coherent.

All I can say at the moment is this:

The most incomprehensible thing about the universe is that it's comprehensible. — Albert Einstein

The universe is under no obligation to make sense to you. — Neil deGrasse Tyson

Whatever Tyson was talking about, it's obvious that the universe, save quantum physics, makes sense as in it behaves in ways that a sensible, intelligent being would: It not only does things - a pebble being smoothened in a river bed to galactic revolutions - it does it elegantly...as if the universe were itself a being of genius intellect (pantheism).

Humans though can be and, sometimes, are idiots!

Therein lies the rub.

I can always say that you see quarks because you only belive in them — Raymond

The quark model (and it is just a model) is based on empiricism, not belief. Believing the model to be a high-fidelity representation of reality is, yes, a belief. But the word itself is a label for a hypothetical set of values of conserved properties. The credibility of that model is based on its predictions matching empirical data. We do not "see quarks". We see the world acting as if it is partly comprised of quarks. So the utility you wish to "throw overboard" is empiricism, which is a call to ignore facts in favour of... what? How we'd like the world to be?

When quarks were introduced in the sixties it took another 10 years to prove their existence and Feynman didn't believe in them, though he believed in partons. — Raymond

Beliefs are irrelevant, beyond that manifest in the requisite confidence that an experiment is worth paying for. Newton didn't believe in quarks either, nor did Einstein, because the concept didn't exist. Ad hominem has no place here. The only questions are: 1) does this predict new or previously unexplained phenomena?, 2) does this contradict empirical facts? Beliefs come _after_, not before.

But what spreads out? If it spreads out it can collapse. — Raymond

Assuming collapse is a thing. But to answer your question, the spatial distribution of the wavefunction spreads out over time. It's just thermodynamics again: if you put the wavefunction in a highly ordered state (measure its position), it will tend toward a less ordered state (spread out).

Something isn't a way? — Raymond

Autocorrect, sorry. "... isn't a wave". A wave by definition is a thing that interferes and diffracts. Electrons interfere and diffract. Positing that electrons aren't waves is therefore gibberish (unless you reject the empirical fact that electrons interfere and diffract).

The quark model (and it is just a model) is based on empiricism, not belief — Kenosha Kid

I see what you mean. I think though, that the scientific approach, the empirical approach involving setting up experiments, watch what's going on, report the fidings, and theorize about it is a belief an Sich. If I don't believe in this approach (I do though), then one can say whatever they want about quarks and leptons, they existing whatever I think about them, but if I don't belief in the approach, or if I don't value it, the quarks will be non-existing for me.

About absorption and emission. Isn't the emitted photon different from the absorbed? A creation and destruction operator are applied in asymptotically free perturbative approach, and can't be applied to a bound system like an atom. The photon absorbed is a different one than the emitted one. Only in Compton scattering they can be interchanged, so it looks. Do you agree with this?

If I don't believe in this approach (I do though), then one can say whatever they want about quarks and leptons, they existing whatever I think about them, but if I don't belief in the approach, or if I don't value it, the quarks will be non-existing for me. — Raymond

Or rather ought to say nothing. Conserved quantities themselves are in fact just statements about the apparent behaviour of the world (empiricism). Quarks are just sets of these quantities. Throwing out empiricism and therefore science ought to delete the concept altogether.

About absorption and emission. Isn't the emitted photon different from the absorbed? A creation and destruction operator are applied in asymptotically free perturbative approach, and can't be applied to a bound system like an atom. The photon absorbed is a different one than the emitted one. Only in Compton scattering they can be interchanged, so it looks. Do you agree with this? — Raymond

No, I've never heard the idea before nor know how to make sense of it. In fact, I tend to go the other, more phenomenological, way. The _least_ we can say about the photon is that it is the transfer of a set of conserved quantities from one system to another, in this case energy, momentum, and angular momentum. Whether it exists in the space-time between those events is debatable (photons are clicks in photon detectors). But if it does, as it is assumed to do, it's a worldline (or rather many worldlines: sum over histories) between its creation and destruction (plus a load of other worldlines that disappear if you believe in collapse, which I don't).

Compton scattering is a destruction of a photon that necessitates the creation of a different photon by a charge that is excited but must immediately de-excite. So on the contrary that's a description of two different photons, not the same one.

Whatever Tyson was talking about, it's obvious that the universe, save quantum physics, makes sense as in it behaves in ways that a sensible, intelligent being would — Agent Smith

The obvious counterexample comes from Einstein himself. One can understand relativity, which is what Einstein meant, but there's nothing intuitive about light having the same speed regardless of whether and how fast you're moving toward or away from it, or that one twin could be years older than another. These are not phenomena that manifest in the day-to-day world and most people (who aren't Einstein) have great difficulty wrapping their heads around it. This is why equations and diagrams are essentially, but they are still abstract to intuition, building upon lots of simpler knowledge via analogy.

Common sense, intuition, and generally what our brains are equipped to deal with, is extremely limited to what happens or appears to happen here on Earth where we live and evolved. It is not equipped to understand what happens on the cosmological scale or the subatomic scale, inside black holes or outside spacetime itself.

Nutso theories that turn out to be true, like molecular theory, germ theory, atomic theory, are things that are already long-accepted in the world we, our parents, and our grandparents were already born into. They are, in that sense, normalised. Relativity is (ahem) relatively normalised, though you'll still find plenty of people on here who think it's pseudoscientific gibberish. We lack a way of explaining quantum theory to lay people as youngsters that would normalised it in the same way.

When Feynman says "You don't understand quantum theory, you just get used to it," he doesn't mean the lay person, he means quantum theorists. Lay people are still far from being "used to" quantum theory in the way they are "used to" atomism. Neither are intuitive, but one of them had a good story. If and when quantum theory has a good story, people will get "used to" it, and think they "understand it". Quantum theorists may get to actually "understand it" in the way they understand relativity (a prerequisite of coming up with a good story to normalise it). (Btw, before the inevitable accusations of elitism and knowledge siloing, there's no barrier to a lay person becoming a quantum theorist beyond putting in the reading time.)

Brains aren't magic or divine. They evolved on Earth to solve problems on Earth. The notion of setting a gold standard for theory on the basis of amenability to intuitive understanding is extremely myopic and has nothing to do with how we really (claim to) understand science beyond the mundane. Layers of analogy down to intuitive ideas are key, not intuitive ideas themselves.

What I meant was that the emission of a photon produces a different photon field configuration as the field used for for exciting an atom. If you excite the electron around the nucleus you use the same photon, of course, but the field emitted looks different than that of a photon coming from it. The photon emitted has a different probability wave associated with it than an incoming photon we shoot at it or that is just impinging with the right frequency and right angular momentum. You can distinguish between the two photon fields. Only in, say, Compton scattering (real photon and electron mediated by virtual electron), the proces is symmetric wrt to time). So it's is simply because the real photon in absorption is not the same as in emission. The both have inversed effect. Energy taken away and given. The excited atom is the same before emission and after absorption. But a ground state absorbing a photon and getting excited is a different process than an excited state emitting a photon and getting silent. The processes are each other reverses, off course. But if you would measure all emitted photons of spontaneous emission of a single atom fixed in space, the distribution would be different from the distribution of photons you use to excite. You can use wavepackets to excite, but wavepackets are not emitted (the photon emitted is spherical symmetric). Well, it's difficult to imagine what really happens, but the state of the emitted photon is different from an absorbed one. A transition of an electron from an excited state to a lower one gives rise to a dipole state. This state can be used again to excite other electron states, but generally the exciting photon does not find itself in such a neat state. The emitted photon has the same energy and angular momentum as the absorbed one. But energy states are degenerate, and both states are energy degenerate but different. As long as the energy and angular momentum are as wished, the atom will get excited. If only it were that easy with my wife... :smile:

The obvious counterexample comes from Einstein himself. One can understand relativity, which is what Einstein meant, but there's nothing intuitive about light having the same speed regardless of whether and how fast you're moving toward or away from it, — Kenosha Kid

Dunno. Isn't light exactly the kind of thing you can't imagine to stand still?

Compton scattering is a destruction of a photon that necessitates the creation of a different photon by a charge that is excited but must immediately de-excite. So on the contrary that's a description of two different photons, not the same one. — Kenosha Kid

You can't see though what direction time goes. For absorltion/,emission both photons have the same energy and angular momentum but their states differ. In CS, both photons have different momenta but these can be interchanged.

You can tell by looking at absorption or emission what direction light goes, by looking at CS you can't.

What I meant was that the emission of a photon produces a different photon field configuration as the field used for for exciting an atom. — Raymond

I don't know what you're trying to say (and I have read on). What is the difference here between a "photon" and a "photon field configuration"? If they mean the same thing, you can just say "photon". Or if you mean the wavefunction, just say "wavefunction". If you mean the state of the EM field, there's only one field, not different fields for emission and absorption.

You say:

the field emitted looks different than that of a photon coming from it. — Raymond

What's emitted is a photon, an excitation of the EM field caused by the de-excitation of the atom, in particular a self-sustaining one (as opposed to virtual photons also excited in the EM field by the presence of electric charges). What's absorbed is that same photon in the example I gave. I'm not following your terminology well enough to be more surgical in my response.

You can't see though what direction time goes. — Raymond

Yes, it too is a reversible process.

For absorltion/,emission both photons have the same energy and angular momentum but their states differ. — Raymond

What does this mean? State is what is described by the wavefunction. This can be cast as a sum of eigenstates of some measurement operator like the Hamiltonian (the energy operator). Different states can have the same energy, but they have different other properties: momentum (positive and negative have same energy), and angular momentum. But the momentum and angular momentum absorbed are also the same as that emitted. It's the same photon.

The _wavefunction_ will be different at absorption to emission, but that doesn't mean it's a different photon: wavefunction are time-dependent.

Again, I'm not following your terminology well enough to know exactly what to say.

don't know what you're trying to say (and I have read on). What is the difference here between a "photon" and a "photon field configuration"? — Kenosha Kid

THe state of the emitted photon, the superposition of fixed momenta fields in Fock space, is a different one that the superposition of states for the absorbed photin. The proces just isn't a proces like that in two interacting assymptotically free states as in QFT, where the incoming and outgoing photons are free. And as you said, the basic interactiins in QFT are time reversible. Absorption and emission are not.

You just can't produce the same photon to use for absorption as the one created by emission. The emitted photon and absorbed one might have the same energy and angular momentum though. The emitted photon has a unique state, while the absorbed can have a wide variety. In CS, both photons are unique and can be interchanged.

Again, the photon is described by a time-dependent wavefunction, which will disperse both in real and reciprocal space thermodynamically. It's still the same wavefunction and same photon. I think we're doomed to just repeat the same statements at each other. (Yours is wrong though :razz: )

Again, the photon is described by a time-dependent wavefunction — Kenosha Kid

We are doomed! But the wavefunction emitted has a different form as the one impinging. Try to construct a wavefunction of a photon that gets absorbed so it looks the same as the emitted one but time reversed, and direct it to the atom...you can't. Sorry... :razz:

I'm not getting what you are saying makes will free. That it evolves? — Yohan
I'll give it a try. — Raymond

Thanks sir. Its hard for me to read though. I am impatient to read longwinded explanations.

Easy. The desired outcome was: discuss philosophy with people more knowledgeable about it than me. The chosen course of action -- to visit a philosophy forum -- was the optimal one. — Kenosha Kid

Fair enough good sir

psst! It's the same serially banned crackpot under yet another name. Don't waste your talents and your time on him.

It seems basically to reduce to charge inside matter.

Again, the photon is described by a time-dependent wavefunction, which will disperse both in real and reciprocal space thermodynamically. It's still the same wavefunction and same photon. I think we're doomed to just repeat the same statements at each other. — Kenosha Kid

Indeed. But the wavefunction coming of an electron orbital has a different shape as a localized wavepacket. If we consider the case of an atom in an excited state which emits a photon by jumping to a lower energy state, most often it will be an electric dipole transition. The impinging wf is a localized wavepacket, in general. Both have the same average energy. But they are different and not each other's image reversed in time. Both states in CS have different energies but are the same under time inversion.

In reciprocal space (momentum space) the wavefunction does not disperse but converge. Momentum values converge to a well-defined value, while position gets more and more dispersed. If the wavefunction has dispersed all over space, the uncertainty in momentum is zero. The space derivative of the wavefunction is zero everywhere, if fully dispersed. So the uncertainty in momentum goes to zero.

Decisions originating in the brain propagate to the peripheral nervous system which contracts muscles and applies forces to the system. The system is not violating any physical principle, when these forces are taken into account.

In general when thinking about free will it is helpful to consider robots. You can program a robot to always move up hill. Does this constitute a proof of free will of the robot?

In general when thinking about free will it is helpful to consider robots. You can program a robot to always move up hill. Does this constitute a proof of free will of the robot — hypericin

The will of the robot is not free. You have subjected its will to the will of the programmer, who pushes a structure of ones and zeroes through a structured circuit by means of a programmed sequence of stored ones and zeros at the rhythm of a the computer clock. The robot is then pushed up by means of basic will processes, which means, electrically charged processes that cause motion. So the will of the robot is in fact directed by the will of the programmer. It is a determined will, like all will, but not free, like unforced determined will, because the will is determined by the programmer.

I wasn't talking about intuition alone. It's as clear as day that the universe makes sense in a rigorously logical sense - there are laws, mathematical to boot, that govern the universe and that extends far beyond mere gut feelings.

If you ask logical sensible answers the universe will answer accordingly. At the same time it can make no sense at all. No law to be discovered. How can the universe be "goverened" by laws? That's merely a way of us to objectivize our knowledge and arises from our longing to govern. By saying that the laws govern, it's actually us who want to govern, by knowledge of these so-called laws. Knowledge is power. Like God was thought to govern and the chosen ones close to Him claimed power in His name. It can't be denied that both God and laws of nature exist. But they don't govern. That happens only in our minds.

The _wavefunction_ will be different at absorption to emission, but that doesn't mean it's a different photon: wavefunction are time-dependent. — Kenosha Kid

I'm not sure I get what you mean here. At absorption to emission? What do you mean? The wavefunction at absorption is a different wavefunction than emission, yes. And a photon is a photon, yes. Both have the same energy yes. The proces of absorption, excitation, and emission is asymmetric in time though. The photon that's absorbed has a different accompanying wavefunction than the emitted one. So if you reverse the "scene" you will be able to see in which direction time flows, as the shapes of both wavefunctions are different. For example, if the wavefunction of the absorbed phòton is a wavepacket localized in space, and the emitted one has a dipole pattern, the process is asymmetric. You can't reverse the dipole configuration (shape) of the wavefunction. So, leaving dispersion aside (which is asymmetric in time) you can actually see if time goes forward or backwards, which means absorption and subsequent emission is an irreversible process (of course you can use a new photon to excite the atom again). Which doesn't mean that absorption and emission don't share a photon with the same energy. And off course, emission can be reversed by absorption or absorption by emission, like an open door can closed and opened. But it's asymmetric in time and the very process is not reversible.

And, again, only the process of a photon scattering with an electron is one of the few processes that actually can be reversed without being able to see in what direction time goes.

If the evolution of the wavefunction in space is a dispersive process then doesn't that mean that that evolution can't be reversed in time?

I wasn't talking about intuition alone. It's as clear as day that the universe makes sense in a rigorously logical sense - there are laws, mathematical to boot, that govern the universe and that extends far beyond mere gut feelings. — Agent Smith

Right, which also holds for quantum theory, a thoroughly logical, mathematical theory but that is intractable for macroscopic systems, hence why a) people don't get it, and b) we can't answer macroscopic questions with it. Quantum theory doesn't want for mathematical foundations: it wants for a compelling narrative for human minds.