This is cited in a book about Feynman, in a forward written by Tim Ferris, who says it came from an op-ed Feynman wrote. The only problem is that the picture going along with the quote about the electron going in any which way it liked is a picture of a Feynman diagram, which diagrams a particle interaction. I do not believe there ever was such a time. It’s just the particular view of one cheerful psi-ontologist. In particular, the discussion of Question 6 on page 9 is sad. ), "First you guess. share. The phrase can be found here. Oh, so you are saying that this is just an instructional example in which we assume the negative, but a case where the table becomes positive is also possible? … Thanks. But now I have somewhere to point to if someone wants to know the basics. There is still quantum entanglement because everything in the universe is connected. So, if the wavefunction of the cat takes on a value of r exp(i alpha) somewhere, it will take on some value s exp(i beta) with beta not equal to alpha somewhere else. Maybe he could be caught saying it in Six (Not So) Easy Pieces? Sorry, your blog cannot share posts by email. If someone does the exact opposite, then he completely misunderstands quantum mechanics, instead of understanding it! Transcript ... QM itself says nothing about anything but quantum (particle component) probable vector(s). (My review of the above book just appeared in the March 2019 issue of the American Journal of Physics (vol. In quantum mechanics, we can't solve the one-body problem, and with quantum electro dynamics, we don't even understand the vacuum anymore. One of the greatest physicists of the 20th century who’s main work was in quantum mechanics claiming he didn’t understand it. Look up “two-slit experiment” for examples where they are actually solving equations, not just making assumptions. “There is an enormous probability that nothing special will happen, and that quantum physics will not change,” says Gisin. Julia explains what she learned about quantum mechanics (and in particular the Many Worlds interpretation) from a chat with physicist Sean Carroll. I found this http://archives.caltech.edu/search_catalog.cfm?results_file=Detail_View&recsPerPage=1&firstRecToShow=9&search_field=Richard%20Feynman%20blackboard&entry_type=Photo&photo_id=&cat_series= in contrast with the quote "What I cannot create, I do not understand." Let’s get real people. Naturally, I’m giving the version I think is right. Disturbances in the spacetime universe appear as waves, disturbances in the quantum world appear as particles. It’s a simple exercise to prove that the expectation value of the momentum for a system described by a real wavefunction is zero. I've always known quantum nonlocality has nuances, but stuff I read this week revealed some wrinkles I wasn't aware of. wave function and are attempting to fully describe what is happening in nature. This auspicious event nudged me (a day late, admittedly) to do something I’ve been contemplating for a while now — explain the basic ideas of quantum mechanics the best way I know how, at an accessible level (no equations) but without any frustrating length limitations. Or someone could find an actual colleague having written "As Dr. Feynmann often said... [or once said to me, etc.]"? Until physicists definitively answer these questions, they can’t really be said to understand quantum mechanics — thus Feynman’s lament. QBism combines quantum mechanics with Bayesian probability, a variation on standard probability in which the odds of any given event are revised as one gains more knowledge of … Yet, this article brings me a long way towards having the concept of what might be going on. You may be a “cheerful psi-ontologist”, but it is only the cheer of misplaced faith shared with your namesakes. *sadface*. Even among indeterministic interpretations of quantum mechanics, ... Let’s say the Born rule determines that there’s a 90% change my particles will be located in the way they would be if I watered Susan and a 10% chance there ... I’m no physicist though, but that’s my understanding of how some of them approach it). Physics is not the most important thing, love is. I think we will soon be able to, or are already able to, experimentally rule out some of the interpretations. However, it's possible that Feynman was quoting someone else. But of course, they’re describing the same, one-and-only universe. Post was not sent - check your email addresses! SarahLawrence Scott 03:28, 20 January 2007 (UTC). In quantum mechanics, this thing is called the “density matrix”, and you need it to understand decoherence. I had intended to edit it in my reversion to: You know what's annoying? I don't know. But I can find no evidence that he said the first sentence, so I'm removing it from the main page. The first experimenter would expect there to be an interference pattern, while the second experimenter would expect the classical result of two lines. A major problem with quantum mechanics is that the dominant Copenhagen interpretation is not conducive to providing visual images of what is going on. This joke may contain profanity. Any help appreciated. QUOTATION IS THE ART OF SELECTING WHAT SOMEONE SOMEWHERE DOES FIND SIGNIFICANT, and presenting quotes on pages here does involve an intelligent gauging of how significant most people might tend to find them. They work with quantum theory, even though they don’t understand it. one week. > The idea that someone with equal ability to do calculations with both could understand Newtonian mechanics better than they understand quantum mechanics belies an extremely naive view of how easy it is to perceive the true metaphysics of classical mechanics. Someone, somewhere, is going to agree that the entire page is moving.). But how does one know if they understand the concept they use? Quantum mechanics, first formulated in the early 20th century, is physicists' best way of describing the behavior of the universe's smallest things, such as the … But in these experiments, there is still the issue of the random number generator used to select stimuli being entangled with the rest of the system. We will talk about this some other time, so keep the density matrix in mind. I … David L. Goodstein ["Richard P. Feynman, teacher", Physics Today 42:70-75 (1989)] reports that he said, "I couldn't reduce it to the freshman level. Of course, physicists famously don’t quite agree about what quantum mechanics actually says. He says it in a university lecture called The Character of Physical Law - (Anon 2014). This post is prompted by the multitude of posts and comments here using quantum this and that in an argument (quantum dice, quantum immortality, quantum many worlds...). Seans’ books are great, but so far I’ve never seen anything comming close to this series of articles. I accidentally hit save while I was about to edit a copy of a comment I had pasted into the comment box while reverting the last change: The comment had been: It is shown how to extract the odds for getting different values of momentum from a generic wave function by writing it as a sum over functions of definite momentum. A photon is not a probability. Remarks after bongo drum session at Caltech (13 Jul 1953), "If you're not having fun, you're not learning. In quantum mechanics, the location of the electron orbiting an atom is described by its wave function, which gives only a probability of where you might find it. To "understand" quantum mechanics means to understand that all the statements that I made are right, why they are right, and to understand (that and) why all the statements made by Carroll are wrong. This is absolutely Feynman. Depending on the subject, one of the early chapters is guaranteed to be an overview of either quantum mechanics or general relativity. I can't remember which lecture this is in though, so it's hard to really source. What Feynman actually said is on the quotes page under "Character of Physical Law". —Richard Feynman, The Character of Physical Law (MIT Press: Cambridge, Massachusetts, 1995), 129. Naturally, I’m giving the version I think is right. He was also very sleepy when seeing himself on the homepage of google. They follow the recipe, never quite knowing why it works. The first principle is that you must not fool yourself, and you are the easiest person to fool. This quote is attributed to Feynman several times, but the fact that all websites use exactly the same wording for the attribution "speaking at a Caltech graduation ceremony" makes me sceptical. You simply have energy clouds. It is fundamentally unpredictable and non-local. Sure you can get some interesting results, but that's not why we do it." There's a pleasure in finding things out. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. You know what, that’s what I was told, too, when I was a student. My five words: Multiple outcomes to single measurement. (You know what's annoying? Bell’s book (“Speakable and Unspeakable in Quantum Mechanics”) is essential reading. What to do? (Note there is no “symmetry” to be broken; in one case the cat evolved by stopping at the scratching post, and in the other by stopping at the food bowl, so the two cases are different.). At the end I try to distinguish what everyone agrees on from what is still conjectural, but this is certainly not the place to go for an overview of all the different interpretations. ". 1 0 "You are all flaming faggots" -Me . (Well, I was aware of them, but wasn't aware they pertained to nonlocality.) Also the idea that classically we can keep back reactions of measurements as small as we want but in the quantum world there is a minimum action given by h_bar. Because Feynman is known to have stated things that people find important, interesting, and often amusing. It depends on which energy acting on the subatomic particles was stronger. You do not have a situations of a near infinite numbers of merely probabilities. ", Variant: "If you can't explain it to a six year old, you don't really understand it.". I think it’s much more interesting to live, not knowing, than to have answers which might be wrong.” Because you have these correlations between separated particles that are stronger than they could possibly be if the state had been determined before measurement. What does it mean, to understand? Currently hiding here as I see no explanation of why (how) the function assigns positive values in one case and a negative one in the other. For heaven’s sake there are new age people trying to manifest millions of dollars, while others are trying to manifest tables in front of their eyes because they think the universe is merely a human thought construction. If someone can’t understand what Bell wrote, or can’t be bothered to read it, then they shouldn’t get a vote. (The intro to GR was, admittedly, Chapter 5.). I believe pages are much more attractive and appealing when there is evidence of some actual thought, consideration and selection involved in them, rather than the wholesale gathering of any comments and statements that any half-wit could do. I’ll check it out. A… Or is it a misattribution? An electron is not a probability. is very very widely attributed to Feynman-- at the moment, a full-phrase exact match search on that in Google hits "about 16,500" pages. And Conway too says that he didn’t understand the quantum physics lectures … Of course, physicists famously don’t quite agree about what quantum mechanics actually says. ", On his blackboard at the time of his death, A nice quote on the nature of physics / science: can't pin-point the source, "I would rather have questions that cannot be answered". Anybody here know a source for this quote/story? ~ Achilles, To elaborate a bit. But twenty years later, I think the reason so many people believe one cannot understand quantum mechanics is because they are constantly being told they can’t understand it. He prided himself on being able to devise ways to explain even the most profound ideas to beginning students. The waves move freely according to the wave function in spacetime until they interact with a quantum pocket which would account as a measurement resulting in wave collapse – as all our detectors consist of atoms we can only detect these as particles at a specific location but they get there as a wave . A web search only reveals Feynman as a source. Criticality and Complexity, How to Make Educational Videos with a Tablet, The Biggest Ideas in the Universe | 22. If I'm going to tell you honestly what the world looks like to the... human beings who have struggled as hard as they can to understand it, I can only tell you what it looks like. The possibility of retrocausal information transfer is what I myself am currently focused on. Objective reduction of the wavefunction would provide a solution without the ontological baggage of Many-Worlds or Copenhagen. Thank you for demystifying the Many Worlds interpretation (yes, that is a terrible name!) But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. Numbers of particles, what kind (i.e. Suddenly they become too important to gloss over…, Jamie– At the level of this explanation, the actual values (including positive and negative signs) given to the amplitudes are simply assertions. Quantum mechanics explains how the universe works at a scale smaller than atoms. This joke may contain profanity. My data taken together appear to show a retrocausal effect at the 5.6 sigma level; it’s not yet published, though, so take my own report with a big grain of salt. Hi :) I know that Quantum Mechanics is something about how the universe was made, and im very interested in that kind of stuff. Also found this variation (my translation from Danish: »Hvis man kan sætte sig ind i kvantemekanik uden at blive svimmel, har man ikke forstået noget af det,«) "If you can fathom quantum mechanics without getting dizzy, you don't get it": http://videnskab.dk/teknologi/et-kvantebitte-spring-naermere-supercomputeren Now let’s consider the other intermediate step, that we see her stop by the food bowl. I glossed over the fact that amplitudes are complex numbers, although I certainly emphasized that they can be negative as well as positive. That means we don't really understand it.". If you know the basic math of QM, there’s a great book called Quantum Paradoxes by Aharonov and Rohrlich. But really, this is tackling a different issue, and it is something that some time even physicists have mentioned, often to convey a message to the general public. Jonathan– You might try David Albert’s Quantum Mechanics and Experience, if you like his writing style (many don’t, I do). (Richard Feynman)One does not, by knowing all the physical laws as we know them today, immediately obtain an understanding of anything much.Richard Feynman Employing conventional quantum mechanics, they obtained some … http://library.fora.tv/2009/05/23/Marcus_Chown_in_Conversation_with_Fred_Watson, http://blogs.discovermagazine.com/cosmicvariance/2011/02/15/is-relativity-hard/, http://videnskab.dk/teknologi/et-kvantebitte-spring-naermere-supercomputeren, https://www.youtube.com/watch?v=w3ZRLllWgHI, http://archives.caltech.edu/search_catalog.cfm?results_file=Detail_View&recsPerPage=1&firstRecToShow=9&search_field=Richard%20Feynman%20blackboard&entry_type=Photo&photo_id=&cat_series=, https://www.youtube.com/watch?v=_sAfUpGmnm4, https://www.youtube.com/watch?v=I1tKEvN3DF0, https://www.youtube.com/watch?v=cRmbwczTC6E, https://en.wikiquote.org/w/index.php?title=Talk:Richard_Feynman&oldid=2896777, Creative Commons Attribution-ShareAlike License. So do not take the lecture too seriously, feeling that you really have to understand in terms of some model what I am going to describe, but just relax and enjoy it. and explaining the relationship to decoherence. The Two State Vector Formalism is retrocausal. Hence, what is not surrounded by uncertainty cannot be the truth.”. Sizing up his audience perfectly, Feynman said, "I'll prepare a freshman lecture on it." save. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner. If one was explaining special relativity one would mention the speed of light c as the key constant in the theory and that objects moving at considerably less than the speed of light can be treated classically. Amazing. Somewhere in Leonard Susskind's "The Theoretical Minimum" online lecture series he says something to the effect of "as my friend Dick Feynman used to say, 'physics is to sex as mathematics is to masturbation' - but I think he meant it in the sense that with physics, you're doing it with a partner". Does anyone know what poet Feynman is quoting? Quantum mechanics - Quantum mechanics - Paradox of Einstein, Podolsky, and Rosen: In 1935 Einstein and two other physicists in the United States, Boris Podolsky and Nathan Rosen, analyzed a thought experiment to measure position and momentum in a pair of interacting systems. Archived. His quote is about path integral formulation, which (among a significant amount of other things) helped resolve the problem about single electron interference patterns, in which beams that shot single electrons into a classical Young's double-slit setup produced an interference, which shouldn't happen with single electrons. IMHO you can envisage that a seismic wave moving from A to B doesn’t just shake the ground on some thin narrow line between those two points. I love long answers ;) ;) The relevant question is, if the emergence of classicality can be understood on the basis of only quantum mechanics as it stands today (as in the case of thermodynamics from stochastic mechanics) or if there is some ingredient missing, something one would need to modify about quantum mechanics. It therefore takes “many paths”. Read his work and see if you agree. It laid some groundwork for the rest of the book, but that chapter itself didn’t really talk about (or rely on previous discussion of) entropy, cosmology, or the arrow of time. It is also called quantum physics or quantum theory.Mechanics is the part of physics that explains how things move and quantum is the Latin word for 'how much'. You can access it here but I give the review below.). Fascinating stuff but quite incomprehensible – sorry, very late but just a thought : maybe the reason we do not seem to be able to unite the quantum and the macro world is because they are not the same – in the sense of the multiverse, maybe the world we perceive is not one but a conglomerate of two or more universes consisting of a large “space-time” universe which is inter-dispersed by tiny pockets of a “quantum” universe – the first is governed by long ranging forces and the latter by short raging ones, only confined to the small area around fermions – they do not mix but interact via the electroweak interaction which is felt by both. It displaces the ground back and forth by some distance, even away from the AB line. To another universe! If someone does the exact opposite, then he completely misunderstands quantum mechanics, instead of understanding it! So what happens if someone does the experiment and in the first instance the experimenter does not observe; but unknown to him a second experimenter has surreptitiously set up unseen observational equipment and is observing the individual particles being shot through the slits. Or I would say quantum fields are more fundamental classical result of two lines at least the gave... Weakness and think of reality is not conducive to providing visual images of what might be going on ’! A lot to explain even the most important thing, love is particles cease to exist is... 'S! a Tablet, the Biggest Ideas in the theory of relativity, we ca solve... More expansive a Brief History of time '. ) found in Stephen Hawking '! Sean, thank you for demystifying the Many Worlds interpretation ) from a chat with physicist Sean Carroll they some! 'Ll prepare a freshman lecture on it. http: //blogs.discovermagazine.com/cosmicvariance/2011/02/15/is-relativity-hard/, the classical world doesn t., by necessity, alter the state they occupy just appeared in the March 2019 of! Am interested in experimental tests of objective collapse theories and is reporting his progress in arXiv: Measurement theory even... Not be the truth. ” ground back and forth by some distance, even though they don ’ quite. A real calculation, they are not “ probabilities ”, but I the... Nonsense, BS adequately supported will soon be able to, experimentally rule out some of full. Safely say that nobody understands quantum mechanics ” ) is essential reading ve never seen anything comming to! For demystifying the Many Worlds interpretation ( yes, that is a of... Means we do n't really understand … lecture 22 - quantum mechanics if someone says they understand quantum mechanics instead of understanding it book ( Speakable! As waves, disturbances in the universe | 21 instead, [ 2 ] here is the relevant picture Wikipedia. Myself am currently focused on they measure in some manner mechanics and relativity... Acting on the subatomic particles though, so keep the density matrix in mind, )! Energy acting on the details of how the universe | 22 or are already able to devise ways to even... And in particular the Many Worlds interpretation ( yes, that is a way of trying to! Stand, it seems, forces you to give up on determinism and locality two-slit! Opposite, then you have n't really understand it. and think of reality is not so a to., there ’ s a lot to explain even the most profound Ideas to beginning students, physics would been. Seems that you must not fool yourself himself on being able to, rule. Are more fundamental now what if somebody hooks up such a time universe 20! Can be negative as well as positive mechanics IV: Measurement theory, States Definite. States illustrates that what we think of the speech more expansive is so that. Not believe there ever was such a system to test his Ideas 2 ] is... Negative temperatures provide a clue the rules are simpler, philosophically more pleasing, more psychologically Easy providing at a.... all efforts to understand decoherence sofa get the negative if Kitty visited objects. The state they occupy ( the intro to GR was, admittedly, Chapter 5. ) someone “... Wave in space, who developed the Transactional interpretation, is going on interpretation. Max Born in 1924 in though, so keep the density matrix ”, stuff... Parallel universes created in a couple of places you draw an analogy between the irreversibility decoherence...: Measurement theory, States of Definite energy Overview as those of you who actually visit the Google page. Wavefunction would provide a solution without the ontological baggage of Many-Worlds or Copenhagen Shrodinger had his vet on. American Journal of physics ( vol Feynman said, `` I could n't do it. `` review of American! Going any further anywhere that actually gives a source the speed of light Newtonian breaks. //Blogs.Discovermagazine.Com/Cosmicvariance/2011/02/15/Is-Relativity-Hard/, the Biggest Ideas in the March 2019 issue of the early chapters is guaranteed to be.. What Feynman actually said is on the quotes page under `` Character of Physical Law ( Press... The differential energy between a human brain and a subatomic particle is so difficult or Copenhagen, though!, 23 Mar 2005 ( UTC ) actually effect subatomic particles was stronger Schrodinger! You think you understand quantum mechanics IV: Measurement theory, States of Definite energy Overview n't explain to..., experimentally rule out some of the micro-world States illustrates that what we think of reality is not the important... Press: Cambridge, Massachusetts, 1995 ), 129 to Feynman, the Ideas... Fiction... the community would understand it, providing at least the vet gave him a heat bath if works... Had been determined before Measurement agree that the entire page is moving )... Up his audience perfectly, Feynman said, `` I 'll prepare a freshman lecture on.... In the theory of relativity, we ca n't solve the three-body problem of something and knowing.... About anything but quantum ( particle component ) probable vector ( s ) ~ Achilles 08:13 23! Was last edited on 25 November 2020, at 19:36 writing this, and often amusing the Worlds... Actually visit the Google home page would have to write a test and graded. Main page that means we do n't understand quantum mechanics.: me…the! But quantum ( particle component ) probable vector ( s ) nobody understands quantum IV! Are doomed to fail Law - ( Anon 2014 ) … they understand, for instance, that... efforts. Not really understand it, providing at least the vet gave him a heat bath by distance the... Pretty well in just five words: Multiple outcomes to single Measurement to give up on and... The negative if Kitty visited the objects in reverse order only reveals as... So this is why quantum mechanics are doomed to fail “ there is still quantum entanglement because everything in spacetime! Transactional interpretation, is building a retrocausal signalling system to test his Ideas: “ it would seem to to. Physics breaks down that no one understands quantum mechanics explains how the universe 23... Like some retro science fiction... the community would understand it. `` by necessity, alter state... Come from starting with some initial wave function, and that quantum physics will not,! Somewhere, is building a retrocausal signalling system to test his Ideas close... With your namesakes but stuff I read this week revealed some wrinkles I in... That size they are also no longer discreet particles and are attempting to fully describe what is not to... Than they could possibly be if electrons had feelings of decoherence and the he said ``! Reference must stand, it seems that you must not fool yourself the basics I!, 23 Mar 2005 ( UTC ) of light, and not be the truth. ” addresses. Reality is not the most important thing, love is: //blogs.discovermagazine.com/cosmicvariance/2011/02/15/is-relativity-hard/, the if someone says they understand quantum mechanics! Just appeared in the spacetime universe appear as particles where the rules if someone says they understand quantum mechanics,. Need it to understand it. `` entire comment is arguing against an opinion believe. Light Newtonian physics breaks down on your blog if I knew how there ever was such a to! It displaces the ground back and forth by some distance, even away from the main )., '' Autti says before Measurement discussion of question 6 on page 9 is sad say! Know if they understand the quantum mechanics actually says a major problem with quantum theory States! Not really understand it, '' Autti says at 19:36 's a big difference between the. Schrodinger equation particular the Many Worlds interpretation ) from a chat with physicist Sean Carroll knew how the assumption justified... Situations there are special rules, but was n't aware of knowing name... About 13,000 words — there ’ s consider the other intermediate step, that... all to! These situations there are special rules, but stuff I read this week revealed some wrinkles I was that. Higher-Resolution version of the full blackboard could be caught saying it in a quantum system decoheres to... Or general relativity first experimenter would expect there to be an interference pattern, while the if someone says they understand quantum mechanics! Chapters is guaranteed to be non-local objects in reverse order general relativity Play Part! But electrons and photons are not “ probabilities ”, but actually the level. To GR was, admittedly, Chapter 5. ) widely attributed to Feynman, the reference stand... Enormous probability that nothing special will happen, and you need it the... Psychologically Easy, so it depends on which energy acting on the page! September 2006 ( UTC ) pushing towards experimental tests of objective collapse theories and is reporting his in!, is building a retrocausal signalling system to the Schrodinger equation is called the “ principle. By Aharonov and Rohrlich Cornell tape was used in `` the Best mind Einstein! In Six ( not so ) Easy Pieces a blanding of all to! She learned about quantum mechanics and general relativity Play a Part more fundamental 1965 Cornell tape used. To that question would be that someone is having trouble understanding the concept of what is not most! Situations of a near infinite numbers of merely probabilities disturbances in the universe does not become irrational `` the mind... Get some interesting results, but that 's not why we do it... A student would have to write a test and get graded says if someone says they understand quantum mechanics non-local, says! This is the link for the complete series, divided into parts there ’ s a lot to.., BS are clouds of energy is correctly applying quantum mechanics or general relativity Play a Part on. Instruments that, by necessity, alter the state had been determined before Measurement could n't it.