I’m inclined to believe that just about everything we now think is fundamental will also eventually be understood as approximate and emergent: gravity and the laws of Newton and Einstein that govern it, the laws of quantum mechanics, even space itself…As readers of this blog know, I agree, because the statement is correct. Particles and spacetime are the two sides of the same basic elements of nature.
Then the trouble starts. Smolin concludes that the laws of nature change, that the universe is fundamentally irreversible, that math is not important, and a lot of other nonsense.
Peter Woit, instead of simply criticizing the mistaken conclusions, also criticizes the correct statement above.
What do we learn from this debate? These two very different men, and probably many around them, both think whatever they want. They do not care about nature or truth; they only care about their personal preferences. They do not care about truth any more. This is especially sad about Peter Woit.
Physics doesn't make sense.
ReplyDeleteHow can one particle go through two different slits at once? How can the particle pass the slits and then, depending on a change to the apparatus, either behave as if it went through just one slit or behave as if it went through both slits AFTER it must already have done just one or the other? Actually, it's worse: the particle goes every conceivable route from one place to the other. If you assume that, your experimental predictions are never wrong. It works, but it doesn't make sense!
If a particle goes one way, to say it goes another is a contradiction. To say it goes lots of differents ways is lots of contradictions. Some people proposed that it skips backwards in time so it can do the route over and over again, but if it did that, the mass of all those time-travelling dopplegangers would bend spacetime. Some people propose lots of universes - with one path of the particle occurring in each. The only effect the universes have on each other is the interference they cause to each other's particles. That is postulating something infinitely bigger than the whole universe just to explain exactly one fundamental phenomenon. For extraordinary claims, extraordinary proof is required. So what is the proof? There isn't any.
Physics is so nonsensical that a lot of people say 'here is a mathematical model; if I apply the model to an experimental situation, it makes accurate predictions about what will happen next; many, many tests have confirmed this; it can be relied upon; I claim nothing further'. Neils Bohr said there is nothing between a measurement called an 'emission of a particle' and a measurement called a 'detection of a particle' - quantum physics is really just a fantasy that somehow captures enough of the truth that it always gives the right answer.
Einstein knew physics didn't make sense. He never denied it's accuracy, but he spent the rest of his life trying to think of an explanation that would make sense of it.
Many people say we shouldn't tell the universe how to be; it is how it is. It only appears strange to us because it is so at odds with our everyday experience. Wrong! Contradictions are contradictions until the concepts are refined so that the contradictions disappear. It has got nothing to do with us clinging to what is familiar. The problem is with physics.
It doesn't make sense. It works; nobody disputes that. That it works doesn't demonstrate that it makes sense. Sense requires absense of nonsense. If contradictions are not nonsense, then anything goes - which is clearly contrary to experience.
Physics doesn't make sense. The only way you can deny it is by very carefully arranging your blinkers and steadfastly and resolutely resisting all demands that you remove them.
Or maybe it is just that physics doesn't make sense to me because I'm too thick to understand it but not too thick to realize I don't understand.
(Anyway, what I mean is I don't think the problem is not caring about nature or truth. Everybody is casting about in different directions because nothing they have heard so far has managed to thoroughly drive out the overpowering sense of being beaten into submission with nonsense.)
Anonymous,
ReplyDeletemany people talk nonsense. But:
Quantum physics makes sense. Wave functions are simple to understand and to imagine. I learned them in high school. The rest of quantum physics follows. So many people say, like you, that quantum physics makes no sense. But you are all wrong. It has no contradictions at all. Contradictions only appear if you cling to false thinking habits, for example, that particles are like small objects. That is wrong, particles are like wavy clouds.
You are right in another topic. "Multiple universes" is nonsense. Quantum physics has no relation to this nonsense. Anybody talking about "multiple universes" needs a therapist. Or a caring partner.
OK, put it this way: when I first heard about special relativity, I was told the story about the train with a light-beam clock on it passing a station. I immediately thought 'Hold on! A clock on the platform would look slow to the passenger for exactly the same reason. They can't both have a clock that runs slower than the other; that is a contradiction'. I wasn't impressed. Later I heard that it wasn't really a contradiction because to compare the clocks fairly, you had to bring the clocks together, and that required one or both of them to accelerate. But I couldn't think how the time on a clock could be related to the acceleration it experienced when the acceleration required to bring the clocks together could be near-instantaneous or very gradual. Only years later did I see the explanation on Wikipedia: the acceleration was equivalent to a gravitational field because of the equivalence principle - if the acceleration was short and sharp, the gravity was strong and so time was greatly slowed for the short duration of the acceleration, and if the acceleration was gradual, the gravity was weak and so time was slowed only a little but for the long duration of the acceleration. The contradiction was resolved by the correct explanation.
ReplyDeleteNow what about quantum mechanics. What is the similar explanation that resolves the contradictions?
Pretty please.
Anonymous,
ReplyDeletequantum physics is the evolution of wave functions. Also water waves behave differently after passing one or two slits. Probably you do not say that water waves make no sense. Wave functions are similar.
"Contradictions" in quantum physics are always invented: either to entertain, or to feel better. If you want to live your life thinking that quantum physics has contradictions and makes no sense, please do. Other people live and think much weirder stuff. This blog is about the search for the theory of everything, not about explaining high school physics. There are so many good physics books: tolle, lege !
Hypothetically, I can look at a distant light source whose light emitted in different directions has been focused by the gravitation of a large intervening body into a beam. Light travelling by the different paths then interferes and creates an interference pattern that can be seen on a screen. Alternatively I can take a telescope and point it at one extreme of the intervening body or another. Any light I see that way can only have come that way around the intervening body and not any other. If photons only interfere with themselves, not with each other (as the respected experts assert - and in which case, comparisons with water don't work), how do you explain that with the telescope, I see light that travelled a particular path, and with the screen I see interference that results from light having travelled all paths, even though it must all have happened many years before I picked up either a telescope or a screen?
ReplyDeleteAccording to special relativity, when you go fast, distances shrink - they have to to explain how you travelled so far in so little time without breaking the speed of light. But then what about photons? They travel so fast that distances disappear altogether. But when that happens, everything must be on top of each other. There is no way to tell which object a photon passes first or whether it ever passes any object. So if a photon is effectively just a plane in a direction perpendicular to its direction of travel, the only way it can know what is out there is to travel in all directions at once - because all the information about what is out there can be combined from all the different perpendicular planes. But to say a photon travelled even in one other direction is a contradiction; to say it travelled in all directions is lots of contradictions. If in order to travel, a photon needs the information obtained by travelling in all directions at once, the conclusion must be either that photons don't exist (because impossible things do not exist) or that they don't travel (because travelling requires impossible behaviour). Well photons move - whether you call it travelling or jumping doesn't matter - but to get the information they need to do it, they would have had to do something impossible (travel in more than one direction at once), so that just leaves that photons cannot exist.
ReplyDeleteWell! Maybe in the Strand Model, that makes sense.
The only observables are crossing switches. Photons are really only an appearance one can infer from the crossing switches. And because they are only really an appearance, that's why they appear to do impossible things.
Anonymous,
ReplyDeletealcohol is bad for the brain!
Clara,
ReplyDeleteIt's OK. I haven't got a brain, so I am immune.