I want my LaTeX

THWOTH wrote:STOP PRESS!! INTUITION IS BOGUS!!

Yep, and that's a really important thing when dealing with modern science. About 100 to 150 years ago, we started seeing things that didn't work well with our intuition that evolved to deal with the world at a certain level of scale. The big confusing things were Einsteinian relativity and Quantum Mechanics.

Both, interestingly, defied two intuitive concepts: lumps of stuff and waves, both of which move and are fairly important for our species. Armed with these intuitions, we delved into the worlds of the very fast and the very small and found our intuitions not to work.

Relativity involved light, something that we think of as moving, and for centuries we had argued about whether it was a corpuscle (to use Newton's idea) or a wave. It turned out to be something really confusing. Like a wave, sort of, maybe, but without a medium, so unlike a wave. Like a corpuscle, maybe, but unlike any other we had experience with, because it only had one speed.

Quantum Mechanics showed wavy and corpuscle-like behavior, depending on how you built and watched the experiment, and then a lot of confused crapola like "particle/wave duality" for decades, mostly because our monkey intuition didn't seem to fit very well.

epepke wrote:

THWOTH wrote:STOP PRESS!! INTUITION IS BOGUS!!

Yep, and that's a really important thing when dealing with modern science. About 100 to 150 years ago, we started seeing things that didn't work well with our intuition that evolved to deal with the world at a certain level of scale. The big confusing things were Einsteinian relativity and Quantum Mechanics.

Both, interestingly, defied two intuitive concepts: lumps of stuff and waves, both of which move and are fairly important for our species. Armed with these intuitions, we delved into the worlds of the very fast and the very small and found our intuitions not to work.

Relativity involved light, something that we think of as moving, and for centuries we had argued about whether it was a corpuscle (to use Newton's idea) or a wave. It turned out to be something really confusing. Like a wave, sort of, maybe, but without a medium, so unlike a wave. Like a corpuscle, maybe, but unlike any other we had experience with, because it only had one speed.

Quantum Mechanics showed wavy and corpuscle-like behavior, depending on how you built and watched the experiment, and then a lot of confused crapola like "particle/wave duality" for decades, mostly because our monkey intuition didn't seem to fit very well.

You both may be confusing intuition with pre-conception. What was confounded by both QM and relativity was people's pre-conceptions.

What epepke said doesn't seem very confusing to me.

Most of my relatives are idiots. Honestly.

THWOTH wrote:What epepke said doesn't seem very confusing to me.

Maybe not, but the phrase, "monkey intuition" was used inappropriately and misleadingly. Relativity and QM theories were both proposed as intuitions, and became accepted theory after many valid experiments.

But epepke was talking about the error in my 'monkey intuition' about thinking of photons colliding head-on as having a combined velocity greater than c. 'Intuition' itself was not really being criticised or dismissed, and my STOP PRESS quip was but a tongue-in-cheek acknowledgement of my personal deficit in this area. And besides, it's not like GR and QM were intuited out of thin air is it? epepke simply explained how and why GR and QM appear counter intuitive to those who's understanding is, like my own, rooted in the physical realm of experience and who might form erroneous concepts in the absence of certain necessary information.

As I said when I joined the thread, I've been accepting of what everyone has been saying about GR but hack posted something which point out that I wasn't really getting it. Thanks to the contributors here I think I've got a little bit more of it now than I did when I arrived.

THWOTH wrote:STOP PRESS!! INTUITION IS BOGUS!!

Translated: Many people had/have misconceptions about relative speeds, based on their experience of the (non-relativistic) everyday world. Einstein followed up his intuition that speeds do not combine in such a simple way when either or both is close to c.
Now do you get the point about "intuition".

Note the smiley, and then move on.

Relativity and qm are not 'intuitive' in any sense.

THWOTH wrote:But epepke was talking about the error in my 'monkey intuition' about thinking of photons colliding head-on as having a combined velocity greater than c. 'Intuition' itself was not really being criticised or dismissed, and my STOP PRESS quip was but a tongue-in-cheek acknowledgement of my personal deficit in this area. And besides, it's not like GR and QM were intuited out of thin air is it? epepke simply explained how and why GR and QM appear counter intuitive to those who's understanding is, like my own, rooted in the physical realm of experience and who might form erroneous concepts in the absence of certain necessary information.

As I said when I joined the thread, I've been accepting of what everyone has been saying about GR but hack posted something which point out that I wasn't really getting it. Thanks to the contributors here I think I've got a little bit more of it now than I did when I arrived.

You understand what I'm saying. I was saying a bit more, though. Both Einsteinian relativity and QM happened because we went as far as we could with monkey intuition, and they stopped. Sure, Einstein and others had some good intuitions, but other monkeys had been scratching their heads about the nature of light for centuries and the specific weirdness of Maxwell's Equations for decades. At first they came up with monkey stuff such as the Luminiferous Æther, a pretty obvious intuition available to any monkey who splashes in water.

I also don't think that many understand what I mean by a monkey intuition. (or maybe they're just being snarky and think they can win points; it's hard to tell with monkeys, who are pant-hooting all the time). A monkey intuition is the intuition that a brain gets from evolution on a period of monkey behavior. Namely, swinging through trees and also spending some time, eventually most of it, on the ground, though the former is a bit better. We got intuitions from this about motion, which is where physics started and still where a lot of physics is. These monkey intuitions involve running into another monkey going in the other direction, and we intuit that it's twice as fast. It ill equips us for dealing with something like light, which always goes at the same speed (though as I've explained, it doesn't always propagate as fast).

Give him a banana!

campermon wrote:Relativity and qm are not 'intuitive' in any sense.

Not to most people at the time, but they were only proposed as intuitions, based on experimental results.

EDIT: In other words, what is or is not "intuitive" depends on the information available at the time.

... In short, a scientific hypothesis IS only an intuition, unless and until it is supported by experiment.

So, this thread has made me go back to -- and hopefully actually take in this time - the Feynman lectures on QM published as "QED : The Strange Theory of Light and Matter." (amazon) I've been curious about the photon for a while now, and though I scanned this book, admittedly without giving it much attention, quite a few years ago now, even the introduction to the book has settled a few things I've been confused about for quite a while.

Feynman says light is a particle. Yeah, it has certain wave-like properties, in certain circumstances, but basically if you're not thinking about photons as particles your getting it wrong. Is this still current?



See what you've made me do now?

THWOTH wrote:Feynman says light is a particle. Yeah, it has certain wave-like properties, in certain circumstances, but basically if you're not thinking about photons as particles your getting it wrong. Is this still current?

Yes. Well, of course, viewing it as a wave works for a lot of cases, too.

The best thing that Feynman said wasn't that light is a particle but that it comes in lumps. That, for me, hits the sweet spot in terms of understanding. It states an important property without trying to define what light is.

"Particle" is just the English word we use for that mysterious thing that makes up everything in the quantum universe including matter and light. It's lumpy, and it's also wavy. You can sort of think of it as a point in some sense, but it's also a kind of blob with a distribution function that extends over space and time.

The thing is that hardly anything in the macroscopic world resembles this kind of thing. The stuff in the macroscopic world is a bunch of these things working together, and a lot averages out, so that we can use a simpler model. Light is a bunch of photons moving fast, and so a lot averages out except for the waviness. Matter is a bunch of particles moving pretty slowly in about the same place, and so a lot averages out except for the lumpiness. These two extreme cases are what we are used to.

I guess the closest thing would be the soliton. It's a self-reinforcing wave in a medium like water that moves. It looks like a moving bump, and people have mistaken them for sea monsters. But I doubt that sea monsters played a huge role in our evolution.

Surprisingly, there's also something pretty similar in our heads, in area 7 of the visual cortex. It's called a Gabor function, and it's a normal curve multiplied by a sinusoidal. It looks a bit like this:



Our brains use something quite like them for edge detection and direction in a plane.

I'm not saying that QM reduces to Gabor functions, not a bit. I'm just trying to give a picture to spark intuition. Now, is that a lump, or is it a wave? It's a bit of each. Seen from far away, too far to see the wiggles, it would look like a dot. A bunch of them together would look like waves.

Incidentally, once, many years ago, I tried using moving Gabor functions to visualize a vector field. I reasoned that, because it corresponded to our best guess of how part of the visual system worked, we could sort of short-cut to it and give a good impression. I found that not only did it work, it worked way too well. When I turned it on, it felt like being hit in the face with a frying pan.

Also, Feynman's QED videos (QED in NZ) are good. I like them better than the book. You can find them on Youtube.

THWOTH wrote:So, this thread has made me go back to -- and hopefully actually take in this time - the Feynman lectures on QM published as "QED : The Strange Theory of Light and Matter." (amazon) I've been curious about the photon for a while now, and though I scanned this book, admittedly without giving it much attention, quite a few years ago now, even the introduction to the book has settled a few things I've been confused about for quite a while.

Feynman says light is a particle. Yeah, it has certain wave-like properties, in certain circumstances, but basically if you're not thinking about photons as particles your getting it wrong. Is this still current?



See what you've made me do now?

The wave-like properties of photons comes from the wavefunction for the particle (ie the photon).