Let "Their" be Light

[Amy]

Well, clearly we aren't going to come up with an actual "solution" to the lightwave/photon problem. But I think we can, at least, explain *why* there is no solution, and I think the reason centers on the line "Any time we try to detect photons, they reliably seem to be in one place."

It isn't possible to detect photons reliably, because there is nothing smaller than a photon that we can use to detect them. (Okay, there are theoretical particles that may be smaller, but we still can't use them.) So any time we try to locate a photon by blasting it with more photons, we will end up altering its location--or else its path--in the process. It's Uncertainty, dude!

Of course, this highly sophisticated analysis is based on 2 years of high school physics, so it's quite likely I'm overlooking something...anyone? Anyone? Bueller?

[firemeboy]

What do you mean we are not going to come up with a solution? I already have! Let me put it in the form of a riddle...

This is an interesting topic and I am afraid I am going to have to do a little research before I dare try to make an intelligent comment on the subject.

[Calfaile]

"Heisenberg may have slept here..."

Isn't this just the wave/paticle duality? According to Heisenberg (and my chem professor) the universe is inherrently "fuzzy", and we can not know both the velocity and the position of a small particle at the same time.
I think this results from an equation where the uncertainty of velocity multiplied by the uncertainty in position is equal to a constant.

Electrons also exhibit the wave/particle duality. The electron is not a little particle circling the nucleus, it is a three dimentional wave! (In chem 11, in the middle of the year, they gathered us up and told us "Forget everything U knew about the atom up to this point, it's all WRONG!!!!!")

Hmmm. University is useful for something after all!

-Calfaile

[Calfaile]

Oops, forgot the reason for my original post: So using Heisenberg's uncertainty theorum, we really CAN tell the precise location of each photon. The photon dosn't "know" when we are looking at it, it just depends on where we "focus" the uncertainty.

-Calfaile

[Murray]

Been a while since I did some thinking on this stuff, but I want to note one thing: Minotaur says "If in the above experiment we placed detectors at slits A and B, no photon would ever be observed going through both A and B. In fact, it seems to be the case that light is always a wave, spread out through space, until it is observed, when it suddenly is a particle." I'm pretty sure that if you do set up detectors to find out which slot the photon goes through, then you don't get the wave pattern. You just get two bars directly behind the slits. That is interesting.

[Ghost Post]

My 20-yr-old college memories agree with Murray's statement. That wave-particle duality thing is one of those things that they just tried to get us to accept; when you're talking about particle physics, the Newtonian rules we originally learned simply don't apply.

I never went beyond Freshman physics, so I don't remember if any resolution was ever reached. But I think I remember hearing about some experiment 9or was it just theory?) that showed that if you try to measure a photon in one way at point A, it will still react the same way at point B? Even if that means transferring information faster than light?

If you really want to get confused, look at Feynman's book on QED (Quantum Electrodynamics), in which light simultaneously moves at all speeds - from zero to infinity.

[araya]

I'm not a physicist, certainly not a particle physicist (hmm, but one of my best friends is, I'll have to ask him) but I don't think the problem is the uncertainty principle. The uncertainly principle says that we can't know both the location and momentum with total certainty - but we can find the location if we totally ruin our chances for getting the momentum, which is good enough for this experiment, since we are interested in whether a single proton is at A or B. If the detectors are placed at A and B and allowed to affect the path of the protons (which they certainly do) then the experiment is ruined, since the diffraction patterns won't show up unless the light is allow to pass (directly) through the slits.

By the way the double-slit experiment was (first) conducted in 1804 by Thomas Young, and was taken as proof of the wave nature of light.

What IS of interest in this problem is the fact that when the protons are not being measured, even when they are fired one at a time they seem to be passing through both of the slits at once, or at least acting as a wave in this way. For instance, if you fire the protons at a very low rate, the diffraction pattern still shows up over time. If you close one of the two slits, then the diffraction pattern goes away (you get one fuzzy band instead) even though the proton *seems* to go through either one slit or the other. It is somehow able to feel out both paths, and interfere with itself! This we would expect of a wave, but when we place detectors at A and B, the proton shows up at one OR the other, not both - which we expect of a particle.

This is quantum mechanics. When both slits are open, the question "which slit did the proton do through" is meaningless. It went through both. Heisenburg steps in when we try to measure the proton - you can't know the path unless you ruin the experiment. In quantum mechanics, the act of measuring the particle is known as "state-vector reduction" or "collapse of the wavefunction". Basically, when the proton is in flight, its position can be considered as a combination of different physical locations (a super-posed quantum level state). When the proton is measured, it is either at one place or another (a classical level location). Somehow the system jumps from one state to another when it is measured. So, how does the proton know we are looking at it? I'm not sure what the Minotaur is referring to, but it seems to be something like "How does state-vector reduction work?" and nobody in the world knows the answer to that question. What we do know is WHEN it happens, and that is anytime we attempt to measure a quantum state by producing a classical-level reaction (one that is perceivable by us).

[AcidFast]

I think that the REAL question here is:

If there were a cat named Schrodinger in a box....

I am a big fan of quantum physics, and I must say that, also being a big fan of Einstein, I am also, like my good friend Al, convinced that there is a simpler explanation than some of the ones that our friends in the field have come up with.

Quantum Physics will try to tell you all kinds of stories about the wave-particle duality, some of them as ridiculous as to wrestle with the nature of reality as a whole. Einstein would not bend. He was convinced that there was a simpler explanation, and even though he was supposedly 'proved' wrong by the very experiment that BobF refers to (more on that later), He still would not bend. I am still with him. Something in me will not let me settle for the explanations that are available to us now. I'm with Einstein. There must be a simpler explanation, we just haven't found it yet...

AcidFast

[Jack]

The most intriguing explanation of the double slit experiment that I have come across is in a book called "The Fabric of Reality" and involves multiple universes that interact at the quantum level. Another involves a reinterpretation of the philosophical foundations of QM which is too long to go into here. Regarding Einstein's comment that God doesn't play dice with the universe, QM theory may not be totally correct (I doubt if any theory is), but it has certaintly given the right predictions to a host of physical phenomena.

[Andy]

Araya - you should fire (or at least reprimand) your spell-checker - it seems to be converting "photon" to "proton." The experiment would likely be similar with protons, but different detectors would be required. Anyway, I don't have anything technical to add, but I offer an alternate view:
There is no reason to expect that subatomic particles should behave in ways that are directly comparable to macroscopic phenomena. "Waves" and "particles" (and "continuity" and a lot of other things) belong to the macroscopic universe. The quantum universe doesn't have to have anything comparable, even though macroscopic phenomena are composed of collections of quantum phenomena (or so we believe). This is somewhat like finding macroscopic patterns in large collections of small dots - such as the text you're reading, which may be composed of electromagnetic waves (at some point in its journey to you), pixels in various colors and/or intensities on a computer monitor, black or colored dots on white paper, etc. The small-scale phenomena don't look much like text when viewed individually. Only when you view them collectively are you able to read the text or see the face or whatever pattern is there. This doesn't mean that the patterns aren't real, but the way they behave as patterns isn't necessarily useful in predicting the behavior of the small-scale components. It may make more sense to ask, "Given the identified behaviors of quantum-scale reality, why do we percieve the things we do at a macroscopic scale?" than to ask, "Given our understanding of macroscopic phenomena, how can we explain microscopic phenomena in the same terms?"

[Amy]

Wow...so if the question has more to do with how we perceive the phenomena, then might it be theoretically possible for us to change the way we perceive them, effectively changing the behavior of matter and energy? I guess this isn't too practical, but it could still be possible in theory. Heavy stuff. Reminds me of Richard Bach's _Illusions_.

[mwf]

I'm putting this all down as the problems you have with see a 4th dimension object in the 3rd dimension.

[Amy]

So the quantum level and the macroscopic level would be like looking at the same 4D object from two different angles?

[AcidFast]

As a matter of fact, Amy, one of the understandings of Quantum Physics is that we actually change reality by observing it.

Take for example an extreme oversimplification of the experiment referred to above by BobF and myself:

A pair of 'paired' quanta are projected in opposite directions from a source point. When quanta A reaches its measuring device, we can measure it a number of ways, and depending on how we measure it, the results can come out differently. No matter how we measure it, however, quanta B always comes out with the same results as quanta A, as if it knew how we were measuring quanta A. We can measure quanta B the same way every time, and come up with a different result every time if we measure quanta A with a different method every time. So the way that we measure quanta A actually seems to effect the outcome ofthe measurement at quanta B, even though they are travelling at the speed of light in opposite directions.

In fact, if no one is familiar with Schrodinger's cat, it is an interesting (if cynical) analogy about the theory that nothing actually happens until we measure it:

If we have a quantum event that has a 50% chance of occurring, put it in a box with a cat and a vial of poison gas. If the quantum event happens, the vial of poison gas is opened and the cat dies. If not, however, the cat will live. Saying that the quantum event does not have a result until we measure it, is like saying that until we open the box, the cat is neither dead nor alive. The cat is in some meta state between life and death until we can open the box and observe whether or not the quantum event happened (in this case, the cat being the measuring device).

Surprisingly enough, much of the physics world thinks exactly that, even though the example of the cat in the box was Einstein's comments on Schrodinger's theory, almost making fun of him.

So Amy, what you proposed about changing the behavior of matter and energy by observation of it alone is EXACTLY how most of the physics world feels about quantum phenomena. All the numbers pretty much support it, even though its a tough pill to swallow. But I'm sticking with Einstein, myself. I think there must be an explanation which is conceivable by the human mind.

[araya]

That's the third time this month my spell-checker has been out of line! Oops. It makes no difference of course, except that perhaps people were wondering what I was talking about.

You're right about the quantum/macroscopic phenomena too, Andy. The only way we can observe the quantum world is by bringing about a macroscopic event - as AcidFast notes, a quantum system reacts to this in sometimes extremely odd ways. In his quanta example, a measurement made on one quanta can instantaneously affect its pair, which could be any distance away - but no information could have been passed between them, unless perhaps it travelled at far faster than the speed of light.

Which brings to mind an interesting problem, proposed by Elitzur and Vaidman in 1993: Imagine a bomb which has a detonator on its nose so sensitive that the slightest touch will set it off. A single photon of light incident on the nose will do this, except that some of the time the detonator is jammed, which means the bomb does not explode and the it is classified a dud. The problem is to find one bomb for which it is certain it is not a dud. The percentage of duds could be very high, but for testing purposes a very large supply is available.

Using classical physics there is no way to solve this problem, but using quantum mechanics there is a solution. In fact, there has been a solution developed which causes NONE of the active bombs to explode, but weeds out all the duds!

I don't want to try and explain it, but read about it here, along with lots of other cool quantum effects: http://matu1.math.auckland.ac.nz/~king/Preprints/book/quantcos/qnonloc/qnonloc.htm

[Ghost Post]

Was it in a Douglas Adams novel where they opened the box... and found the cat had escaped?

I would really appreciate it if someone could clarify the question "How does the photon know we are looking at it?". "Looking" involves a photon(s) imparting energy on a cone photoreceptor (or rod, as the case may be). Photons are very, very small; retinal photoreceptors are relatively large. Does it just come back to the practical problem of us having crude perception, as I think Amy alluded to in the original post?

I am fully aware that this is over-simplified and most probably way off the track.

[AcidFast]

Adam, I am not sure what exactly you mean by your question, but will try to explain what I think you mean:

When we say 'observe' or 'measure', we are talking about an indirect measurement of a photon or electron, etc. For example, when we shoot electrons at a certain type of screen, it causes the screen to glow in the spot that the electron hit it. The same is true for photons when they strike certain metals.

If your question was more along the lines of "how do we see?" then it doesn't really matter how big the photon is, it will still have the effect of activating the photoreceptors in your eye.

If your question was about the changing of behavior of the photon at the point of measurement, then:
The point of measurement is tough to pin down. Physicists have been trying to do exactly that for decades. We can shoot a quantum particle (let's call them "quons") from a 'quon gun' at a detector, we know it will act as a wave because of where it lands, but when it lands, it is obviously a particle, because it strikes the detector at a specific point. so it would seem that the quon will act like a wave until it is measured, when it seems to instantly change to a particle. And it seems to be able to predict the point of measurement because when we change it (say, move the screen to a different distance), the quan will follow suit exactly.

Also, I would like to add at this time that in order to appreciate the difference between the wave and the particle, we must consider a macroscopic event to compare. It is not so simple as one object which acts like two different objects at different times. If you were to make a wave in a pool of water, and watch it go across to the other side, then take a gun and shoot a bullet through the water, that is the equivalent ofthe difference between a wave and a particle. So a wave is not actually something that moves from A to B, it is more like a concentrated 'pushing' of particles which goes from A to B. Or picture yourself running around the stands of a ball park as the audience around you did the 'wave'. The wave-particle duality would be like you disappearing at the start of the wave, the audience doing the wave from one side to the other, and you reappearing at the other side as the wave disappears. Impossible, you say? Happens every day in the quantum world.

So, I guess we don't really know how the photon knows we are looking at it. But it seems to, doesn't it? maybe these 'particles' are actually some kind of sentient beings sent here just to mess with humans' minds.........

[Ghost Post]

Thanks AcidFast; pretty sure I understand the problem now.

Apologies for being a bit dim - I think I'll stick to the riddles and Chuck's chess puzzles.

[Dave]

I think the answer lies more in understanding differences in concepts. The wavefront represents a physical abstract of all the possible mathematical points that the single photon could pass through at any given time. The photon only occupies one of them and continues along that single path. We can observe that path if we place a detector in front of it. If a detector was placed as described then there would be a fair likelihood of a detection because the detectors are significant larger than the particles being detected, thus not only covering many possible locations for our single photon, but also occupying the most probable locations for our single photon. Hence, we likely observe it. The photon for its part doesn't care who observes it, it just wants to know who gave it the headache by placing the detector in front of it.

[AcidFast]

Adam, please don't apologize. It's no problem, I love talking about this stuff, it really fascinates me. I actually have spent a great deal of time studying this topic in my own time (I've actually never taken a course in this in school...). Please, ask away, and I can only hope that I will help to get others interested in this stuff. I, personally, can't get enough of it...

Of course, then you have the older and still unsolved problem of the medium. Every wave has to have a medium. In other words, there has to be something that is waving, like water, air, the audience in my ball-park analogy above. But with light and quantum particles, there doesn't seem to be any substance that actually waves. Light has no problem moving right through a vacuum (nothing), and neither do quantum particles. So what is it that is actually waving when we talk about light waves? We still don't know.

[Buzzsaw]

Gee, what ever happened to puzzles like 'The 3 lights' or 'Most unique' that even a farmer has a chance of solving? (these icons sure come in handy)

[AcidFast]

Don't underestimate a farmer, Buzzsaw, remember, Albert Einstein was a lowly clerk when he developed his Theory of Relativity

[firemeboy]

Ok, this is way out of my realm here, but I will throw my comments into the ring and you can ignore them, or laugh at them, whatever you choose. The only classes I have had where this topic was covered was when I was a freshman in High School. I was only 13 and remember next to nothing. However here are my thoughts. This may be of more interest for science fiction fans out there. What if light is actually nothing more than a big slinky? We have all seen the wave demonstrations using a slinky. What if there was some type of fabric out there in space that is completely undetectable. Anything that causes 'light' is actually just causing a wave in this 'fabric'. The light causing thing simply effects this fabric and makes it visible to our eyes/sensors. The little photons are acting like a wave (just like a slinky can act like a wave) but when we actually try to trap the photons, they becomes simply a slinky... er photon. A slinky acts like a solid object, but can act like a wave as well. Light is nothing more that a visible wave in this undetectablt fabric.

[Ghost Post]

The evidence:
Light travels at a constant speed relative to everything. Meaning no matter how fast you are going in the same direction the light is traveling when you measure its speed relative to you it will always be 186,000 miles per second (in a vacuum). This suggests that we do not see the whole picture.

Light is seen as a sigle photonic point when measure by instruments engineered in a 3 dimensional world.

Light definitely show properties of being a wave.

Waves themselves are not matter and do not have substance rather they are patterns of movement within a medium created by motion.

conclusion:
We do not see light in its entire. light exists as a multidimensional substance which we only see when it comes in phase with our dimension. This is why we can only see a single point (photon) when we measure it yet it has the properties of a wave.
Imagine that you could only perceive a thin horizontal slice of ocean and you were watching a jelly fish moving up and down with the current. To you it would seem like the jelly fish was disappearing and reappearing. You could even cause the jelly's frequency of appearance to change by moving back in forth in your small slice of ocean. Same concept.
Our slice of ocean is very small.

I beleive that is the answer to the riddle.

[Murray]

I've heard these arguments before, but they don't explain to me how measuring the location of the photon eliminates the wave pattern. I mean, it's a given that we aren't seeing the whole picture, but how does looking at one part of the picture make another part disappear?

[mwf]

jennifermarwhit I agree with you as I have said earler. This is a problem of seeing a higher dimensional object is our space.

Untill we can see into the next dimension this will always be a problem to us.

[Buzzsaw]

To AcidFast: I am a farmer and i ain't no Einstein. Feel free to underestimate me all you wish. It beats the tar out of being overestimated when you can't deliver the goods. Hopefully there are a few Swiss patent clerks among us who can get those melons to market.

[Amy]

Okay, let me see if I understand this argument: photons and light waves are two different projections of the phenomenon known as light, which is actually a higher-dimensional construct, onto our three-dimensional space? (I just want to make sure that I'm grasping the concept--still not sure if I buy it or not.)

[Andy]

A little farther out - approaching Schrodinger's territory...
The photons that pass through the slits interact with a detector (usually film) and thereafter cease to exist as photons. Even if the photons are fired one at a time, nothing actually happens (i.e. the waveform doesn't collapse) until someone removes the film, develops it, and looks at it. Until then, the interactions resulting in detection have happened only potentially. No actual interactions occur until the developed film is observed; at that time, the entire set of waves collapses and an image appears. Since the waves all collapse at once, the plan to fire only one photon at a time has no effect. It would be effective only if someone observed the result after each photon. Has anyone conducted this variation?
Re Schrodinger's cat - could the cat be the first observer? If so, then the wave function may collapse before the researcher opens the box. If not, then maybe nothing happens until the last observer observes it - all previous observations just contribute to a growing wave function.

[Joel]

I found this web page with an alternate explanation. I just perused it rather quickly. someone with a little more physics/math background might want to check it out.
http://www.newtonphysics.on.ca/HEISENBERG/Chapter7.html

[Ghost Post]

Sheesh, you go away for a weekend, and look how many messages are posted!

Anyway, the way I've held the wave/particle duality in my mind can be described with the 'waves in water' analogy: The more energy you put into a wave, the more readily-detected it gets. The 'peaks and troughs' get higher, and they interact in different ways with obstacles in the medium. If you put a huge amount of energy into a 'wave', it starts acting like separate droplets of water, each with a more particle-like identity.

The same holds, after a fashion, with matter and energy. Individual photons have no mass, but they do have a gravitational effect. As the total energy of the photon goes up, the gravitational effect goes up (with the E=mc^2 ratio we've all heard of), and the wave's behavior appears more particle-like. I.e. the wave function drops off faster and faster at the 'edges' of the particle. Thus, an electron is a very fuzzy particle, often better described as a wave function. A proton, being heavier, has a far more distinct wave function, and is usually easiest to model as a distinct particle.

In effect, I suspect that the 'duality' is a matter of perception. Even something as big as a human has a wave function, giving it a finite probability of instantly appearing on the moon -- it's just the probability of that happening within the lifetime of the universe is vanishingly small.

[Amy]

So the old adage, "Nothing is impossible except skiing through a revolving door" is inaccurate--theoretically, even that is possible (though probably not worth taking the chance on).

[firemeboy]

I am not familiar with this cat in a box thing. Does anybody know a good site that explains this? (Maybe all in one syllable words)

[Quailman]

I think I understood what Jennifer said, although most of this theory is over my head. Way over my head.

This may explain why I can walk down the street and not see into the backyard of the house across the way that has a seemingly solid 6' fence around the whole yard, but when I drive down the same street, I can plainly see that the woman who lives there wears a red bikini. The fence is 6" wide cedar pickets, about 1/8" to 1/4" apart.

[Ghost Post]

The best explanation I've ever heard for the quantum measurement process was given by the Harvard physicist Sydney Coleman. I hope I can do justice to his description of the many-universes theory.

The question the Minotaur posed was: how does the photon know that it is being observed? Crackpots (or con men?) like Roger Penrose have attributed to human beings special powers over the quantum universe and have raked in small fortunes from people eager to believe. In reality, no special powers are needed. All that is necessary is to reduce human beings to the level of crude matter. (Evidently Yoda was wrong!)

Every kind of matter has a wave/particle duality. Even the protons, neutrons, and electrons in your brain have this duality. You, the observer are inextricably a part of the quantum system being observed. Every thought you have corresponds to a certain configuration of waves/particles inside your head. It doesn't matter if you observe the photon directly with your eyes or if you are using some kind of light detector which converts the number of detected photons into a number on your computer screen. The detector, being composed of matter, is also part of the quantum system.

Now, back to the problem: How does the photon know it is being detected? We have placed detectors over both slits to see if the photon actually goes through both. Let's step through what happens when you shoot one photon towards the slits.

The initial state is:

photon to slit 1 + photon to slit 2


After the photon wave hits the detectors, the quantum state is:

(photon to slit 1 AND detector 1 registers)
+
(photon to slit 2 AND detector 2 registers)


After you come over and examine the results of the experiment, the quantum state is:

(photon to slit 1 AND detector 1 registers
AND you think detector 1 registers)
+
(photon to slit 2 AND detector 2 registers
AND you think detector 2 registers)


So, the photon really has gone through both slits, but the funny thing is, your thinking process has also become disjointed. You are
now in a superposition of two seemingly contradictory states, just like Shrodinger's Cat!

To illustrate this, we can look at the similar situation when you have the box containing the cat. Before you open the box, the state is:

alive cat + dead cat


After you open the box, the state is:

(alive cat + you think the cat is alive)
+
(dead cat + you think the cat is dead)


Again, we see that the observer has been pulled into a tricky quantum situation. In each case, you think you see only one outcome, but in the full quantum system, there is another state of your mind in which you think you see the other outcome.

This theory is called the Many-Universes Interpretation (probably a misnomer) because if we assume that each person can only think they see one possible outcome, then the two possible brain-states are disconnected from each other and each defines its own seperate perceived universe. When you make an observation, you are really just finding out which of the universes your stream of consciousness is in. The photon doesn't know that is being observed. But, if you get too close to it, your mind's state will be dragged along with it as it traverses all of its possible trajectories.

As an afterthought, here is my own crazy crackpot idea. What if the assumption that people can only think one outcome is not correct? Maybe some mental illnesses are caused by people seeing more than one outcome and not being able to resolve the contradictions. (I guess this idea has been explored a little in movies such as Sliding Doors and The Double Life of Veronique.)

[Ghost Post]

I don't believe light is either a wave or a particle. It, like everything else exists in several dimensions, only 4 of which we observe (i.e. X,Y,Z axes and time). When we observe something we summarise the complete object into our observable dimensions. This does not give us the complete picture so we sometimes get confused results such as in your experiment.

If you imagined observing only shadows on a wall. Looking at the shadows gives you some information about the forms which pass in front of the light source and you would believe that they are exactly the shapes that you see. In truth, however, they are more than just those distorted 2-dimensional shapes.

What I am trying to say is that light "behaves" like a wave when you construct an experiment to observe the wave characteristics of light and "behaves" like a particle when you want to observe its quantum characteristics.

It's like asking, "Is that desk heavy or brown?". You could construct an experiment to prove each. It would "behave" brown in a colour matching experiment and "behave" heavy when you try to lift it.

[Amy]

Sean--your "shadows on the wall" analogy sounds like Plato's in _The Republic_. He said that whatever ordinary humans perceive as reality is really just the shadow-like reflection of a higher, absolute reality. His pupil Aristotle took issue with this, saying (if I remember correctly) that the only reality that exists for humans is the one that they perceive. What this wave/particle discussion now suggests to me is the idea that in a way, they were both right: we can only perceive one particular reflection or projection of "reality," but that perception itself *is* our reality. And that's why our reality sometimes appears contradictory: we can sometimes see a particular phenomenon from more than one angle, but we can't see them all at once, so when we try to superimpose them it comes out looking like a cubist painting--something that doesn't register as "reality" to us at all.

To cleverly segue into my comment on Sanction's post: it does indeed seem plausible to me that people who do perceive more than one reflection of reality at a time would be, for all practical purposes, insane--even though they were seeing nothing that wasn't, in a sense, real. The superposition of one projected reality onto another, in our limited universe, would be like the superposition of two waves: they would add up to something that looked like neither one, and that perhaps wouldn't even make sense as a wave produced by itself. Likewise, the juxtaposition of two equally possible realities could create an "impossible" one--something that just doesn't make sense as a reality.

The best exploration I know of this idea (the kind of insanity that results from perceiving two realities with equal clarity) is in Stephen King's _The Waste Lands_ (the third book in the _Dark Tower_ series). It has to do with a time traveler who goes back and alters the time stream so that the events he has experienced could not have happened the way he remembers them. He then begins to have two sets of competing memories--one of the original time stream and one of the altered time stream he has created. I don't know of any other author who has explored the potential paradoxes of time travel in quite this way, though Roger Zelazny [oops, I spelled this wrong in my original post] has handled it in a somewhat similar way (instead of one person with two sets of memories, you get two distinct people--with the same identity). But that's a tale for another forum.



[This message has been edited by Amy (edited 11-17-1999).]

[Ghost Post]

Re: being insane: by some of the older definitions of mental illness, Physicists, Poets, Shamans, and Saints could all be classed as insane. They see/hear/perceive/apprehend things that are outside of 'normal' experience. Fortunately, they perform useful functions, and rarely cause too much trouble...

More seriously, there are rare people who can visualize four or more spatial dimensions. (Try visualizing a hypercube, and rotating it... I can do it on my computer, but the whole is beyond my comprehension. If you like that kind of imagery, try reading E.A. Abbot's "Flatland" and the 'sequel' (by a different author, whose name I forget. Barron??), "Sphereland". I'd love to hear the descriptions by one who has also studied physics of the wave/particle question...

[Amy]

But a few of them cause enough trouble to make up for all the rest. :-)

I found _Sphereland_ vastly inferior to _Flatland_, because the original was primarily a work of social satire, and the sequel, in my opinion, completely misread that aspect of it. He wanted to use Abott's world to talk about space-time (something I don't feel it was inherently suited for), and he felt like he couldn't do that without first updating the attitudes of its inhabitants. So he made them more enlightened--disregarding the fact that the "flatness" of the world was a symbol for narrowmindedness. The book was still okay, but I thought its use of Abbot's universe was inappropriate.

[Ghost Post]

To the earlier question - how does light change its characteristics depending on how we observe it?
It does not. It is just tricky for us to comprehend something that acts as both a particle (photon) and a wave. Since a particle is something solid with mass and a wave is only the summation of inertial changes caused buy something of mass (force) bumping into another something causing it to move and bump into yet another something. So we are perplexed that light can travel through a vacuum and effectively impact whatever it hits at the other end (like all life on the planet earth) - yet when observed it shows strong symtoms of being a wave. We all know a wave can not travel through a vacuum. You have to have something to make a wave in.

What MWF, Sean, and myself have been proposing is that light is a "substance" that exists in more dimensions than we are capable of observing. We only get to see this substance when it phases into our observable portion of time and space.
This is how light can have the power to impact photo sensitive material and still move as a wave.

It is not that light changes its properties as we observe it - it is that we change the way we observe it. And up until very recently the notion of deminsions outside of our observable 4 (three if we ignore time) was considered hog wash. So in a 4 dimensional world light would have to change itself when we measured it for us to maintain the illusion that there is nothing out there we can not know.
Funny for a long time scientists would rather attribute light particles with cognitive reasoning ablity than admit the universe was something more than wo/man could ever hope to comprehend.