Introduction

Well, let's begin this lecture on quantum mechanics. To some exceptical I want to explain to you, not quantum mechanics, but again how we have been coping with various ideas as we've made progress. Now, some physicists believe that we know all the basic rules of science pretty well. There is nothing really mysterious missing. We know [00:00:29]alecko away [0.4s], gravity and all the other primary forces. And we think we know some about the inner-molecular forces or the nuclear forces. On the other hand, they've had to admit that something like 90 to 95 percent of the matter in the universe, they don't know anything about. Calculating one way, there must be a great deal mask the Universe. Counting everything they know, they find they missing something within ninety and ninety nine percent of the mass. So physics doesn't know everything yet. The question is how much do they really know? Now you should understand one thing. Science never tells you why, it tells you what. Newton's law of gravity told you 'how' something fell. Indeed, it was in connection with gravity. Newton said, I don't make hypotheses. I only can tell you how it acts, not why, nor can I give you the details. In fact, Newton did not believe in action of a distance. He thought it was ridiculous that any sensible person would believe that two things interact when they were separated. But you've gotten used to the idea. You find nothing strange about the Sun's gravitational field affecting the Earth, and the Earth's gravitational effect being the moon. You are used to the idea now, but Newton's time that was not really considered sensible philosophy. Now, at the end of the eighteen hundreds near nineteen hundreds, physics was going quite well and people were smug about what they knew. But there were some symbols indicating that things were not right. For example, spectral lines occur discrete things, but all about physics ahead was continuous - smooth variation. There was the black body radiation, which is given the temperature what is this fusion of frequencies of the radiation. And, you know, when you heat up, a rod is dark, becomes dark red, it gradually moves up the white heat. It's a color change - that's changing the distribution. Has a function temperature, what's the distribution of light emitted by radiating body? Who ideally want being a black body. Well, they had a theory which fit into one end, but gave infinity to the other end. They had a theory for the other end, gave infinity to the first end. It was unsatisfactory. Max Planck fitted the data with a curve. It fit beautifully. He said to himself: “This fit is not chance. There must be reason behind it. There must be a theory by which I can deduce this distribution. So, out to try and find a theory.” He had a great deal trouble. Sooner or later he latched on a method which you know from calculus. You divide thing up in a finite number of pieces. You take the sum and then you take the limit as the largest interval goes to zero. Well, he tried that with the energy. He broke things up to a bunch of the energy pack sizes and then tried to take a limit. Every time he took the limit, the distribution disappeared. When he left the limit of final size, he had this distribution. In fact, the size he left it finally was Planck's concept. He found apparently that energy occurs in pieces, discrete chunks, because that was what fitted it here. He delivered this thing about around Christmas vacation in nineteen hundred. It didn't really catch on for a long while. Einstein connected with the photoelectric effect, which is to shine light on a medal, and when you get to a certain frequency, the medal will eliminate, no, emit, photons or electrons. Otherwise will not. There were sharp things, and he again uses quantum that began to get people and quanta. And we had the old quantum theory which tried to account for things. The quanta were emitted [00:04:41]as [0.0s] discrete pieces and Bohr made a strange model, looking very much like the solar system. He tried to account for the spectral line spacing. Now those spaces have been known for mathematical reasons. Or he really found a form as it fitted the distribution of lines - for various materials. And they fitted quite well. Well, we tried quantum mechanics, but it lingered around until... Still... Well, let's back up. When a electron ray, no, moves the straight line, you're all right. But if it bends around, it's supposed to radiate. And we proved this experiment in the lab and ensured how it radiates. But in the Bohr model, the electron was running around, and it should have radiated and it should have collapsed like that. But obviously, molecules in the world are pretty stable. Otherwise you would be here. So we had a large number of troubles like that. In about 1925 two people started with new ideas. Heisenberg started with the idea that Einstein had and once believed in, about only dealing with those things you could measure.

Arrays of spectral lines you can measure #QuantumMechanics

So he started writing down arrays of spectral lines that he could measure other such things. And he produced a quantum mechanics. Which was surprisingly good, all things considered. Schroedinger, on the other hand, thought about waves and produced the wave mechanics, which were differential equations. Now you've had enough mathematics to remember, matrices have eigenvalues which are discrete and differential equations have eigenvalues which are discrete. So both theories could account for the discrete nature of the spectral lines and various other things which have been coming up slowly in quantum mechanics. Schroedinger and Eckart Carl, I like it, showed, that these two theories as much as they different were equivalent one to another in the sense that you say, ha, the high school geometry you learned Euclidean and ALEC geometry are equivalent. You can prove the theory one way or the other. But in fact, you can't. Some theories we approved both ways. But sometimes the [00:06:56]allied-method [0.0s] is the only way you're ever are going to get a proof. Sometimes the synthetic one is about the only one you can do. So yes, there are equal, but no, not quite. And in fact, shortly afterwards, Dirac come up with some generalized Q vectors, which were very generalized from what... Heisenberg had done. And there was also a group theory approach about the variance of this and that. So there were a number of different approaches to quantum mechanics. But different as they were, they're common for the same things. Now, I want to do well on this point: I've said it last lecture. I said, one time earlier. Still, you can have different theories which account for the same phenomena. Given phenomena, it is not possible to go to a unique theory. No way. It just doesn't work that way. Now, let me discuss how Plank's experience affected my career. I said to myself, Max Planck found something fitted very, very well and he was led to a significant result. When I calculate for people, let me calculate in terms of the functions which they could understand for which they might create a theory. Let me not fiddle around with these dumb polynomials, that most of the numerical analysis and statisticians use, they sell them off ever have any physical meaning? So if I'm going to do some calculate for somebody, well I go to go lunch with them and talk about the kind of functions he believes in, the kind of things he thinks apply to his field and then try to calculate in those kinds of terms, hoping that if I get a spectacular fit, the man will do what Max Planck did, discover something great. Well, I never had that greatest success. I did, however, get some scientists to see much more in their field than they had by using the appropriate functions. Thus, history, because I want to be associated to great things, affected the way I behave. I behave, so I thought I have a chance to be associate with something great, such as quantum mechanics. Well, I didn't hit it. I did some good things. So, this is an example of what I'm trying to teach you. You look at the world, how it behaves. You say: "oh that's the way great work is done. Let me behave that way. Maybe I will be involved in some other great work." Now, to illustrate this matter of not having the same explanation, I've tried for a decade to get back to the theory, at one point around here, a student quarrel with is professor very badly. And I took over running a PhD thesis. I found that he was measuring, using random input, measuring various outputs and trying to establish correlation as to the structure of what was happening. Thus, you might very well, have a chemical plant. You look at the inputs, you look at temperatures and so on, and you try, and look at the output, to deduce what is the equivalence network theory structure of the chemical plan. I found that it was well known, meaning almost nobody bothered to mention it, but it was true that there could be very different electrical circuits giving exactly the same output for the input that they were theoretically indistinguishable. That's another example I'm saying, you cannot from data go to unique theory. Much as you might want to, it isn't possible. Therefore, if somebody has some ideas and you have some ideas that are quite different about the same thing, it does not follow that either of you are wrong. The theories can be different. Now, the real mechanics dates for about 1925 has had tremendous success. It's more successful probably than any other theory when you consider how many small detail things it has successfully predicted. It's amazing.

The trouble with with quantum mechanics...

Now, the trouble with quantum mechanics is that we are large animals and quantum mechanics are concerned with very small details of atoms. You're not used to it. They don't behave necessarily the way big things behave. Therefore, the way we think doesn't seem to fit the way quantum mechanics behaves - if you believe in mechanics. You see our ways of thinking how we see where part of evolution, those ways of thinking which did seem to match the big material world, which you lived in, meant that those ancestors survived and were your parents. [Those who didn't think quite so straight weren't your ancestors. So naturally, the kind of thinking you can do comes from dealing with a fairly large world. Now, the situation was the Newtonian mechanics, which you familiar with, a counteroffer to normal small details. It predicted unknown planets. It predicted a great many unknown effects. Polarized light was predicted successfully. Nevertheless, at both ends it didn't fit. At the high end of large masses, great velocities and great distances, relativity took over, special theory and general theory. At the very small end quantum mechanics took over. So a very, very well verified theory over hundreds of years from Newton's time to practically round early nineteen hundreds. It reigned supreme. Fit it all everything. And yet, at both ends it was wrong - in the sense that it doesn't really predict as well as the newer theories predict. Now, Newton thought, more or less, now he was pretty cagey when you read him, he thought that light was particles because, light goes straight lines. Now, he knew that there had to be some wave-like motion because he knew about Newton's rings and other things would somehow light had its fits. It fitted together, sometimes so reinforced, sometimes it was dark. So he knew about this, but he seemed to have a favorite, as you read him, he is favoring particles. But he doesn't really say 'it must be', he merely uses a lot, because light goes on straight lines, after all. And particles go on straight lines. Waves don't seem to. Nevertheless, in time, wave theory replaced particle theory for a long while. It's very likely the optics you learned, if you took optics courses, were always based on wave theory that light were wave motioned. And like waves the ocean, if you have very small things, especially, you have a very wide one, the waves tend to go fairly straight. And in fact, around the object, you will find diffraction rings of shadow behind it. And you will find a remarkable prediction, if you take a coin and shine light, and you follow me, there should in the exact middle of the black of small white light spot. And you can find it if you search hard enough and look with adequate equipment. So a prediction made was found to be true.

Quantum mechanics asserts; wave and particle theory are partially right

Now, the thing that happens is that we now tend to believe in, quantum mechanics' asserts that things are neither waves nor particles, that both the wave theory and particle theory were partially right. And what comes about is, that you sort of see the particles when the light falls on a photographic plate, it falls right there and develops that grain. But it's also has a pattern. The two slit experiment, you remember, you shine light through two slits and you find a wave like pattern depending on its space of your two slits. But the photon must have gone through one those slits and not the other. But then how for that wave pattern depend upon the width of the thing. So you say, well, you know, it was a wave and wave went through both slits. But somehow that wave became a particle when it hit the photographic plate to develop the grain. So. Light is a wave and a particle. It's both and it's neither. Now, since 1925, this has been more or less accepted belief, and since twenty five to ninety five its quite a few years and every professor of quantum mechanics has said, in one way or another, I cannot explain how it can be both a particle and a wave, you'll have to get used to it. And it is surprising as you work long enough with quantum mechanics, you do get used to the idea that things are neither particles nor waves, and they're both. It's not a thought that you would think very well. And let me make a slight digression to give you something to think about. You are familiar, there are smells that dogs cannot... The dogs is smelling you can't. You're familiar there're various birds can see frequencies of light, you can't see. There are certainly sounds high pitches that dogs can hear, you can't hear. And there taste some taste as some people can taste smell other ones can't.

There are thoughts you can not think

So there are stimuli which you cannot detect - being built the way you are. Why do you get mad when I suggest that your mind's wired the way you... it is. There are thoughts you cannot think. And I suggest you, a candidate is the wave-particle duality. Our mind wasn't wired that way and we have enormous trouble trying to think of how a particle can be a wave and particle the same time. Now, the original stuff was more or less like what you think of ways as particles. But Davisson and Germer at Bell-Labs shot electrons at a graiding and got diffraction just as if it were a wave. And it's been generally accepted that the Davisson-Germer experiment, for which Davisson got Nobel Price, did in fact showed that particles looked like waves as well as waves looks like particles. That they are just dual things about the same thing. Well, this has produced the enormous sea of mysticism. Bohr I think is the reason why there is a, what is called the Copenhagen interpretation of quantum mechanics. Named really after Bohr. Because Bohr had an institute at Copenhagen, which is well supported in privity, every early physicist went through a place and spent some years there at one time or other. Bohr was really a Vienna positivist at heart. And he explained things in what is called the Copenhagen interpretation. There is not one unique one. That's a general philosophy about wave-particle duality and complementarity. The wave and particle are complements, together. You look at one way or you look at another. You can't look at it both at one time there complimentary descriptions of the same thing. And they generally produce a lot of mysticism about how many things, in fact are complementary. You describe it one way, you describe it another. And while they conflict, they don't. You use one one-way and one another way. Thus, this tabletop I would regard a class of licessee as being solid. In a class of physics, I'll say, well, almost all the tabletop is empty space. There's just a few atoms, electrons scattered around thinly in a whole place. The different we use some different ways. It's not always accepted. The original founders did not accept the Copenhagen interpretation Schroedinger, Heisenberg. Einstein particularly, but De Broglie and Pauli and others, all of them, more or less rejected the Copenhagen interpretation, which is horror the dominating religions, as it were the Catholic religion in the middle ages. You're a Catholic or you're out. Well, that's about the way it is in physics. There are heretics all around the place. A guy named BOEM and various other ones they haven't been heretic, too - a lot of us who are heretics, who don't quite believe the Copenhagen interpretation. Because it's got a lot of mysterious things. For one thing, the whole idea of what the particles were in the Matrix or the wave, born to declared one day, "oh, the square of the wavefunction...", really the absolute value of the square,"...is the probability that it will be someplace". And the same way, the square of the composed of the Matrix, which were complex numbers, were the probabilities, meaning the intensities of the lives. Unfortunately, as you look at it, you don't know what they mean by probability. There are two different things, at least, in probability. There's the probability of a unique event. And there's a probability of a whole bunch of events. So you typically think probability is the ratio of the success to the total number of trials when you go to infinity. That's a typical one. But you see, that doesn't fit the why told you about calculating the probability of the [00:20:47]bomoself [0.0s] of the atmosphere. You don't get a frequent number of trials. You either do it or you don't.

Probability is a limiting the ration of repeated trials

So it's clear that the idea that probability is a limiting ratio of repeated trials will not fit many, many situations. And our boy, Dirac, observed that when one photon goes through the two-slit experiment, it interacts with itself, without the other photons. Because no matter what the light intensity is, you get the same pattern. And if you go so low, a light intensity, that, by enlarge is only one photon, the apparatus at time, you still get the pattern. So it's clear in the photons are referring with themselves, not with the other photons running through the thing. So it's pretty clear that they ought to be interpreting the probability in quantum mechanics as being the probability of a unique event, not an average over a larger trials. But you can read quantum mechanics [00:21:45]in there, [0.2s] people flopping back and forth from one description another. It's very badly [00:21:49]malovers [0.0s] what they mean by probability. It's a very awkward [00:21:53]selvi. [0.0s] Now, when I say Bohr did what he did and what I say Schroedinger and Heisenberg did, they were feeling their way forward. They did not know what they were doing. This is a way a new theory comes up. He explains a few things that you hope will explain more as you gradually build up and develop. They developed the theory. They didn't know, and I told you a moment ago, we really don't understand it anyhow. Nevertheless, we are able to use it. And this is one of the points I want to bring up. Even if you cannot or our minds are not wired to understand some phenomena. That does not mean we cannot build a mathematical structure which will enable us to predict reliably. That's roughly what we've done in quantum mechanics. You get used to quantum mechanics, but under pressure, almost everybody, Feynman certainly, there is a... You just have to accept some things you cannot stand, namely the wave-particle duality. After that, the rest goes along with you don't really understand that. So something we can not understand, we have nevertheless built a theory. Had that bears on your future, I've told you repeatedly that my predecessor at Bell Labs did the easy problems, that seems to me we did the hard ones and we left the worst ones, to people coming afterwards. We've done most easy problems as you attack more difficult problems, it's going to be much harder. Take, for example, the understanding of the human mind. You presume we have some electrical engineering, you know, one technique. Break thing up the black boxes and with comparative few interconnections, one can do the analysis of a complicated network circuit provided there are not too many interconnections. If there are too many interconnections, you're going to have trouble. The other approach we have is if a thing is highly repetitive, such as accessible mechanics, we can build up a theory which tells you how it will behave. Well, the brain obviously is a very complicated thing. If it were highly regular, we could perhaps go out through this mechanics. And if it were a block here and a block there and block there, loosely interconnected, we can go out it the way we do circuit analysis. But all the evidence is, that this is neither. Yes, speeches in some region, but it's connected quite intimately with large of other regions. There aren't any nice separable parts much as we wish there were. There are some regions which seem to do something, but you want to be careful. If you are talking to your mother in New York and somebody in Kansas cuts the telephone line, one doesn't conclude that the speech is originating or read processed in Kansas. It may be only the transmission line. The habit of thinking that the mind is where the thinking occurs is very, very widespread. But it may only be the communication channel because there is one terrible fact. You can take one cell animals and train them in the sense that after a while they will go down this thing and turn right rather than turning it random. Well, a one cell animal hasn't got a nervous system, but it can learn.

All learning does not occur in the nervous system

Therefore, all learning does not occur in the nervous system. In simple, very simple animals, there is no nervous system to work with. It must be done some other way. So we really don't know much what we're doing. We tended to think that the nervous system, the connecting wires of the telephone company is a telephone company. Rather than asking more the question: isn't it really the people talking to the people that matter, rather the telephone line connecting it? I don't know. We don't know. But you're going to work in these more complicated things because we've done the easy problems. And so one of the things you have is you may be able to build a mathematical model which will work pretty well predicting, without genuinely understanding. And if you predict / produce a model and somebody says, well, what's the meaning of this? You say: I don't know. It doesn't matter. It’s success we predicts. It's not satisfactory. But that's what we have done in quantum mechanics. We've done it since nineteen twenty five at least, if not nineteen hundred. We've done exactly that and got away with it. More or less. Now, because we had probability in quantum mechanics, there was immediate hope that below what we could observe, there was a deterministic where we were only seeing the random results of it. But below it was deterministic. Well, I know I've been proved that there were no hidden variables is a word that was nothing regular to belief it. But it was found that the theorem was not we approved. So somebody else proved it. There has been a sequence of proof and this proof of hidden variables. The chief one is still dominant, its that there is nothing below the probabilistic version of what the wave-function tells you. That probably is particle happen, or probably that will happen, but there is no mechanical thing below that which got definite. They can't prove it because any proof of that kind of thing must rest on a large number of other assumptions. You don't prove something with just a few assumptions. So they have this awkward thing of trying to believe that below at the very bottom of particles is a essential randomness in the universe. Well, it's not too widely accepted. On the other hand, of philosophers tried to jump on it and conclude that that was where free will lay. After all, if molecule bangs on molecule and everything is predictable, where's this free will or all the other things you think you've got? Well, I wouldn't bet on using quantum mechanics reduce any free will, although the latest book by the guy in England, he wrote The Emperor's Clothes, he has written another one, tries to somehow rather connect the uncertainty quantum mechanics up with freedom of your action.

Whether there is freedom of choice

It doesn't make sense to me, but he does like it. So you have a problem of whether there is freedom of choice, whether world is in fact random or whether it's deterministic. You can pick what you want. We have no way of proving anything. It is a religious question, as a religious question for a number of reasons. Most religions have a God which punishes you for ill and rewards you for good. But if everything is perfectly determinate [00:28:58]you hold, [0.5s] you could do what you did. There wasn't any free will. What's this God who is punish you for doing what you had to do? It's not too popular. Therefore, if you're highly religious, you just don't care for the idea that the whole universe is completely determinate. Even with our randomness at the bottom, there is no freewill or anything else like this, it's kind of hard to reconcile. On the other hand, there are other sides that are equally hard to reconcile. For example, the other side, God, being infinitely merciful. This was pushed to the limit by one the Buddhist sects around the thousand A.D. in Japan, the Emerald Buddha, which if I had to choose a religious sect, I'd pick that one. The general belief was the Emerald Buddha was infinitely merciful. And if when you died, no matter how evil life you led, if when you died you had to appeal to be the Buddha, you will go to the Western Paradise immediately. No question. After all, God was infinitely forgivable, infinitely merciful, it doesn't matter what you did, he would forgive you. Well, you can see the problem religions have between these various things, and you can see how what you are going to believe in quantum mechanics will depend to a great set upon your view of religion.

Religion

Now, religion is a very strange thing in organized religions with [00:30:27]hiding [0.0s] a structure, if you want listen at least not to your religion, but listen to somebody else's. You will get the impression sometimes that the priest or the minister has got a contract with God, and if he delivers his part, God will deliver his part. Certainly in one religion, which I was a consultant for a while, it's pretty clear that if you give enough money, they do enough religious things, your grandmother will now go up to heaven immediately. Contract job. You will find a fair when people say, well, we will do so and so and then such a such will happen. We will pray for you and you will be saved. One religion, originally the Muhammad one, Muhammad knowing this, was annoyed, to say at least, and he said, you as individual face God [00:31:19]want to [0.0s] want us nobody between you and God. As part of the reason why the name comes, you face God directly and you just ask God, what is it God, you want me to do? There is no negotiating in the original. Well, organized religions generally get some negotiation in, so they will have a position. And this is what you find in most religions. Sooner or later, a good deal structure which doesn't fit in too well with the founding fathers. The [00:31:48]boot [0.0s] again wanted no part of having an organized church. The [00:31:53]Bush [0.0s] religion now is highly organized. And the Christian religion is much different. [00:32:00]You remember Christ, that did go all to hell with it. I saw around his church because he didn't really behave yourself properly. [4.8s] Well, he didn't think too much of it. Move on, got a great hierarchy. So all religions tend to do this. And it comes down to this problem, it's not separate from quantum mechanics. Your religion will to some extent, determine what you will believe about the world. No, I'm not [00:32:22]condemning [0.0s] it. What you believe, what the world may influence your religion, but it's very likely be a religious question how you will react to quantum mechanics and various things said it's a very, very awkward question when you come down to it. Now, I personally do not believe it's worth arguing freedom of will or any other things based upon our current beliefs of quantum mechanics. I think the attempt to argue about how God or the world is that part of the world, you relation to God, that part that you should try to argue that the basis of science currently believed, does it seem sensible to me at all? It does going to change our beliefs about current science, and it ought not to be that we change our ideas of sciences, God changes. It doesn't seem likely. But there is the stuck position. If you believe the materialistic world, how do things that are not materialistic affect the motion of molecules? How do ideas or how does God come in and affect the motion molecules so that you saw this happening? That will happen. When I took a psychology course back in the thirties, the problem was one of the solved by what they called psycho physical parallelism. There was a physical world, a psychological world, and the statement was made that these two go on parallel tracks. There's no interaction, but they perfectly correspond. That seemed absolutely ridiculous to me at the time. But you are faced with this problem. If you think that is two different things, how does this materialistic world change because of this other world? Where is the interaction occur? How does occur? Is it limited to you or does it also fly cats and dogs? Do they have free will? Does a mouse have free will does a worm have free will? These are awkward questions that they have best answer, not by appealing to quantum mechanics, but appealing to what you believe, because this is probably just as likely or better. Now, quantum mechanics got worse. A guy named Alain Aspect in Paris did some experiments. You sent off a particle this way, a particle this way. And we believe they have spins in opposite directions. This way, but it might be plain, but wherever polarization is, one does, that's the opposite.

In quantum mechanics the measurement determines

Now, we also believe in quantum mechanics that the measurement determines before that there's a [00:35:03]probability distribution, [0.6s] but the measurement puts it in a definite state. Thus, the thing had a probability [00:35:09]distribution, [0.0s] when the photon finally hit the photographic plate, the probable distribution collapse to one point and it hit right that one point. Well, we make this measurement, six meters up instantaneously, this is found in the opposite. Not with the velocity of light, but instantaneous. Now, we set the [00:35:34]crept up. [0.1s] So after they're separated, only then do we choose which way we'll set this one to measure this will be found the opposite [00:35:41]say. [0.0s] It violates, in some sense, relativity, which says you can't signal usefully fashion of loss of light, but then that's not useful signaling. Apparently, it's not. In fact, when I heard Alain Aspect talk one time in Chicago, there was a question afterwards about what relations at bear to relativity. And he said, I'd rather not discuss the question. I've kicked myself ever since for not raising mindset. Why don't you want to discuss it? But I didn't. And so I don't know why he doesn't, because it's a very awkward problem. Now, I can swing a searchlight so fast that the end of the beam is moving fast we've lost your light, but that doesn't mean I can communicate from there to there by that beam. I'd go from here to here, but not from there to there. So that things can go fast. I've lost too. Light isn't really too bad, but it's bothersome. This kind of experiment, which I call entangled, wants to do parts or entangle they had a common source. They are now connected to something here which will affect that instantaneously. Well, that says something happened on Mars instantaneously. It has this effect here. Two particles, once connected and tangled, are permanently entangled in one behavior can instantaneously transport the other. This is action at a distance, but it's non-local action. We've been used to the idea that something's going to happen here. The effect has got to come through and I can catch the effect before it gets here. And measure what it is. No, this happens instantaneously. Einstein did not like that one bit.

EPR paper; Bell inequalities

He got to his buddies, Podolsky and Rosen, they wrote the EPR paper, which they tried to show there are some limitations of kind of things you could measure and produce many qualities. And these led to a guy named Bell producing some much more serious "Bell inequalities" which quantum mechanics has to obey. You can't have every possible measure. Only some kind of thing is going to happen, if that's true. But this instantaneous action at a distance is disconcerting to most of us. I find it very disconcerting, very. Things across the universe instantaneously happens there a million light years away, the sullor responds the other way immediately. When you measure once up, there the other goes. Now, is it true that the way the measurement sets the distribution. This is the belief. And in fact, the belief goes further. Generally in the Copenhagen interpretation. You have to have some conscious mind: measure. Some consciousness is required to set the wave-function. Well, if you can believe that, typical interpretation then I say to you, from the Big Bang until consciousness arose in the universe, the whole universe could be no particular state because it doesn't settle down to the state. Until this measure by some conscious mind. But that doesn't go with me as well as you either. So although that's the official doctrine of measurement, that the measurement is not fixed until someone conscious measures up in the season, doesn't go. In fact, Schroedinger one of the founders, invented a cat. He has a cat in a box. He has a detector for photoelectric, no, for a electron coming by from some radioactive particle with 50/50 chance. And if the particle goes by, the Geiger counter trips, the poison bottle is up and the cat's dead. If it doesn't trip up the cat is open. While official former quantum mechanics says the cat is neither dead nor alive until you look. That's the famous Schroendiger cat. You can see that we're not in very good shape in quantum mechanics. It is the dominant theory. It's the only one we got. Its doing very well. But philosophically speaking, it's got a large number of things to give you a headache, to say least.

Non-local effects

Now, besides the Alain Aspect one or another non-local effects or such things.... Now, I don't pretend to understand. And particularly the word understand. I am in the same position I told you St. Augustin around six hundred eighty, St. Augustin says, I know what time is until you ask me. And then I don't know what time it is. I think I know what understanding is. I think I know I understand something, until you ask me. I can not write a program which will do understanding or cope with the thing. No way. I haven't a glimmer of idea of how to write a program which can cope with the word "understand". Yet I'm reasonably confident that I understand something. And you a reasonable cope, you understand some things. Well, we're in a bad way. We don't really know what we're doing. [00:40:55] It's a very [00:40:55]dac-waxing [0.0s] problem we are in. Now, I've been trying this course all the way along to get you to realize that while science has been very, very successful in many areas, it's not the end. I recall the case's simulation I told you, very carefully. If I have a simulation and the simulation says A and some expert who's got life experience says, no, that's not right. What do I do? I've worked out my philosophy. If it's a slowly changing technology, I bet on the person with experience. I've got great faith and intuition.

Intuition is based on the past and we're moving in a different world

If, on the other hand, it's a rapidly changing technology, I bet on the simulation. Because intuition is based on the past and we're moving in a different world. Very different world. That's the problem you will face continually. You would like to proceed scientifically. Science is never going to give you exact answers. It is in spite of the DNA trial stuff down at Los Angles. Science never really proved anything. And I'll give you a talk on one day about what science does and doesn't do under the title of epistemology. What else can we know? What can't we know? We really don't know. But you came through evolution or God put it in you, either way you want. What a hell of that intuition provided the intuition was built up in those circumstances you are now operating in. If it was built up a certain task which are different, then of course the story is quite different. The intuition is counter-productive. And I saw that enormously with my predecessors who were successful doing mathematics one way, and they knew computers were no good. They did a thousand things to one way or another oppose oncoming computers. And at lunch they I discussed with [00:43:00]X [0.0s] Dean how much still the school is resisting. The obvious fact that machines are around are going to be around permanently, and why the hell don't we get used to the idea? Why don't we, for example in calculus, adopt what was available in 60? Programs let you do all that damn analytic equations in algebra and everything else. They're around, there available. The range of papers written by a blind programmer. All I can think is that I know the guy quite well. And when he wrote the program and did it at M.I.T., it was as good as undergraduate at M.I.T. and it was about as cheap. Using the old whirlwind, which was expensive machine. Machine costs come down, the programs got better. Now such programs of analytic integration will beat any undergraduate in speed, cost, range of application completely. Why are we still [00:43:57]own the [0.1s] old things? I don't know. We have not really come to terms, but society cannot flip flop overnight. In sympathy, we all were living through chaotic times. We've got enough chaos now. Nevertheless, it seems to me that we have been rather miss adopting and coming to terms with what the machines will be. I keep saying by 1920, no, 2020 laptop computers with enormous memories of all kinds of stuff should be readily available to student. You should be able to walk into class with your laptop computer and enough stuff there for the content of all the textbooks you'll be using that term, if not all the textbooks you'll be using while you're here, along with all the techniques and methods, right on this. You can call up punch differentiation - there will be, punch integration - there will be. We ought to be somewhere as near there then. We could do it, whether we should or not its another problem and I waffle some days I think there's something we're miss and sometimes I think, well, maybe we do have to go slowly. Now we're moving also into another area which you're going to be worrisome. So we are beginning to be able to hold a single atom right there. And know we've got one atom right there. Up until very recently we couldn't. But we're beginning to do this. But when we get a single atom and we can tag it, say it's got, we put it in an excited state, we ship it through the two-slit experiment, we should know whether it went through that slit or asset by where the, [00:45:44]I mean, [0.1s] particle comes from. And so this uncertainty principle comes out of quantum mechanics. Is it so good? That isn't so good at all. We may be able to measure whether that theoretical thing that we cannot know, position and velocity, which I put in the notes on digital filters, is nothing more than a Fourier transform theory. A theorem of Fourier transforms says, the variability, second moment, of variable times the variability of its conjugate variable, this Fourier transform must exceed a fixed cost. That's exactly what you have in quantum mechanics. The uncertainty in the position multiplied by uncertainty and the momentum must exceed the fixed costs. They are the consequence, variables of which transforms one or the other. Is strictly mathematical theorem. It arises because you have a linear theory. Every linear theory must have an uncertainty principle. We put what we see in quantum mechanics. We put it in there. One, we created a linear theory. We have put a lot in of what we now see. More than you think. Much more. That's all, the world is rather difficult. And what we're learning gradually is we're learning, I'm going to repeat this quite a few more time, we are slowly as we come to terms with computers, learning about ourselves. Physics began as remote as it could from us. We've done pretty well, those thing. We're simply being closed in more and more ourselves, and I've been preaching at you. Your education was bad. You were told too much about the external world. You were not told enough about human beings. But human beings are the heart. Moral is the heart of your business. Human beings are the heart of your business. I've often said, I'd rather have a high moral team that have real good weapons. The best weapon I could give you cannot compensate for low moral. No way. It's far more important. But we're giving you here [00:47:56]maniéres [0.0s] course in hardware, partly because we know how to tell you that - we don't know how to tell you the other things. So we tend to tell you what we know. But I've done this course. I've deliberately told already many things that I don't know. I'll making you think about it. I tell you frankly, I am not going to give you answers. My job is to make you think. So we'll see you again next week.