In this series of short lectures, Feynman reduces (except for gravity and radioactivity) the whole of the universe to quantum electrodynamics or QED.* QED involves the relationship between photons (light) and electrons (matter), or quantum phenomena, the interaction of which (electrons emit/give up and absorb/get photons/particles of light) creates all of the atoms and elements in the universe.

Feynman uses light’s refraction to illustrate the relationship between electrons and photons. To understand light, one has to lose “common sense,” he says. Light does strange things. We understand light not as specifically identified photon movement but in terms of probability. “I am not going to explain how the photons actually ‘decide’ whether to bounce back or go through [an opening]; that is not known,” he writes, and then adds, “(Probably the question has no meaning.)” Light seeks the fastest (shortest) route in its movement from A to B, but it borrows or uses paths that are adjacent. When light moves through a small opening, it also spreads out. In this regard, he writes that “light doesn’t really travel only in a straight line; it ‘smells’ the neighboring paths around it and uses a small core of nearby space.”Electron movement is strange as well. Electrons jump from one path to another and positive electrons (positrons) go backward in time. The book quickly gets technical. It is filled with Feynman diagrams and I can’t say I grasped much.

Feynman is describing quantum phenomena but describing is different than understanding. “While I am describing to you how Nature works,” he writes, “you won’t understand why Nature works that way.” “My physics students don’t understand it….That is because I don’t understand it. Nobody does.” This makes his quote above, “Probably the question has no meaning,” particularly interesting as Feynman seems to be saying that, in the end, we can only describe how nature works, but not why it works the way it does. By extension, is Feynman saying that there are no ultimate explanations (e.g., God, Deist design) for the cosmos and how it operates, and that Nature just Is?

*“The theory describes all the phenomena of the physical world except the gravitational effect, the thing that holds you in your seats,..and radioactive phenomena.” QED is “a horrible name,” Feynman concedes. The theory also describes what goes on inside the nucleus itself, which are the quarks and gluons, and involve some 400 (and counting) subparticles.

When I look at the political landscape in my country today, it just seems as though complexity is simply too much for human beings to even deal. But somehow, we have been able to survive, a few more generations anyway, with this wedge of complexity inserted into the good old pie of life as usual. That increase in complexity comes down to getting to know nature Herself. Nature is a She when the extraordinary science explainer Richard Feynman writes. He gives you the sense that She cannot be easily not fully understood by the likes of any mortal, even if you are one of us who has spent many years studying some part of her. He makes it clear, that it's perfectly alright to get lost in the details. But he is also convincing, and rightly, that if we could grasp even a small part of it through our efforts, it would blow our minds.

QED is a slim book, limited to four lectures, designed for those of us who did not study a subject that can really only be understood if you study it. He chose the topics carefully, late in his life, to just open a single manageable can of worms and try to show the wonder, and how far from intuition the truth really can be.

I am one of those readers that is ready to dive in a little more. Like someone that knows a few words of Spanish and can understand it ok, but has never seriously sat down to study exactly how these people are saying the same exact things we are but in a way that doesn't make sense. And an appropriate analogy, many of us make huge assumptions about how different someone who speaks another language is, simply because our intuition is not able to pierce the format of the information we are presented with. I have watched all the science shows on TV, and as I get older, I am trying to set aside some time to actually sit down with some scratch paper, and maybe just pick up a few of these wonders I've heard about, and really try to grasp the evidence, that they say is there for anyone that looks, but is so far from easy! I know the rules of nature are there, and the outcomes of them are detected by my senses everyday, but the rules just never make the front page of... well, our shared reality as human beings. These things they are finding make our reality, but about which we are more or less clueless, have really changed what it means to understand. There's understand, as in repeating what someone else is saying, which is more like being a parrot in terms of understanding. And there's understand, as grasping the proofs that convince all serious scientists completely no matter their country or language, because they are... proof!

The most harmful politicians today argue about whether or not proven science is real, maybe just to protect some fossil fuel lawyers from liability they fudge the most basic statistics regarding global tempurature, or maybe just to get an angry mob going. So someone with that thick a head is not going to be interested in how we as humanity have taken certain mysteries about how Nature actually works, from three decimal places in accuracy, to six or seven, in one lifetime. But it is a big deal, and Feynman manages to lightly let on about that as perhaps more wondrous, than why glass only reflects one to four percent of light back, and never more no matter how much you change the thickness! This is actually a more astounding discovery by newton, in my opinion, than gravity, it's so weird! And so not clarifying, or reassuring... it just is. It is simply truth.

Starting as a fresh graduate in Los Alamos serving during wartime, he's one of the good ones that turned beatnik, and generously devoted some of himself to the daunting task of trying to relate to the public that the real basics about our universe... are so complicated and not tidy, that it takes years just to be ready to talk about light.

So, knowing all this, all I wanted was to have a few big Aha! moments, a few things to remind me that the nature of reality is itself mysterious, and big, and not at all as simple as my senses and my brain make it out to be. Maybe I needed this service, because I felt like I was losing some of my grip in terms of being up to speed with where we really are - no matter how many people want to yell and shout and send us back in time when the class quiz was easier... we really are uncovering astounding things and that sense of mystery makes life more tolerable somehow. He did not disappoint.

Have you ever heard that nothing can go faster than the speed of light? It's not true - light can go faster or slower than the speed of light. And when it does... it turns in a particular direction! Indeed, particles and electrons and all that tiny stuff that makes up everything liquid, solid and airy, most of it has a habit of turning this way or that whenever it interacts, and swelling and shrinking a bit is also not uncommon, like a super tiny infinitely complex pinball machine that makes up... everything! So when a 'beam' of light moves through the atoms that make up the invisible air... it is really hitting electrons which will just absorb it, and then possibly, spit out a new photon heading in the same direction! And so something as simple as a little beam of light travelling a tiny distance, could be doing it in a million different possible ways with no way to predict it, because it is so beyond complicated!

We really do occupy this priveleged perspective, where things seem mechanical, and clunky and solid, water pours, stone is heavy, air is transparent... but the truth, the Truth as in Natural truth... is simply beyond even the smartest brain's ability to estimate, and a computer can only estimate probability. One rock, seemingly dead and lifeless, is actually jam packed with spinning, turning, absorbing, light emitting electrons! It is heavy, because it is so packed with moving energy!

And I really need this right now, when people are so committed to making us confused, and stuck, making us miss this miraculous realities we are translating into our limited languages, just so we will obey their lust for concentrating our attention into short term power, turning us all into rocks they can throw.

I got four... four WOWs from this book. I can't promise I understood even a quarter of it perfectly, clearly, the way a student of physics can. But it's not a gloss, it's not cheap or just a tourist brochure, he really did try to be plain, and clear, about how complicated just one little piece of the rules of the universe - that of light - really is. It's wonderful, it grounds my sense of reality - that there is such a thing as Truth, and pretty much anything we think or feel or sense, especially anything that can be said in only one sentence... is more like whistling a little tune (or passing wind) than making even a flake of the reality of Nature better known, as it has come down to us today, clearer than it has ever been in history, but with so far still to go.

Science is the main reason why going back is just ridiculous and willfully ignorant. It's like saying you'd like to go back to when you didn't know that touching a hot burner on the stove would hurt. Who would want to know the world less, to have our experts be less knowledgeable less skilled, to be more in the dark, when we have so many things to get right still, and so many problems yet to resolve?

...il modo di cui disponiamo per descrivere la Natura ci risulta, in generale, incomprensibile.

Ho sempre ammirato Richard Feynman per il modo così spontaneo e coinvolgente di affrontare tematiche complesse e incomprensibili (come le definisce lui stesso in quest'opera). Con semplicità, credo che riesca ad avvicinare anche il lettore meno avvezzo al mondo della fisica quantistica e ad affascinarlo. In quest'opera, in particolare, si è addentrato nella spiegazione precisa della luce, della sua natura e delle sue caratteristiche, affrontando l'elettrodinamica quantistica non solo in modo divulgativo, ma anche attraverso formule, grafici ed esperimenti. Particolarità che ha reso la lettura meno leggera di altre sue opere, ma mai meno interessante o coinvolgente: Feynman si rivolge al lettore comprendendo la difficoltà della materia, condividendo con lui la complessità di una lettura del mondo che a volte non è pienamente comprensibile nemmeno agli scienziati stessi.

La Natura è sempre apparsa intricatissima e caotica finché, andando avanti, cominciamo a distinguere contorni e a formulare teorie; allora emerge un po' di chiarezza e le cose appaiono più semplici.

Enjoyed Feymans simple expressions of complicated phenomenon. Last chapter was the best.

QED is fascinating. The book quite piqued my interest in the subject, but I did struggle to understand thoroughly what was happening. While this is more my fault than Feynman’s I had to give 3. With better knowledge on my end it would surely be a 4 or 5.

Oh my God this is an absolute gem! Most likely my most favourite physics book, at least till now!

Beautiful intro to QED, for the laypeople, for the physics students, for the physicists - for anyone, basically. Not some easy-to-chew pop-science book though - this contains serious calculations and explanations of QED, how it explains all the familiar properties of light and so on.

You'll have to spend a teensy bit of effort going through it if you don't have some exposure to complex numbers and some quantum mechanics, but don't worry - this is a completely self-contained book. The Feynman charisma will get you going just fine.

The quantum world is wild and I don’t understand it. Feynman assures me that is ok because nobody understands it.

Feynman's true genius lies not in his unique understanding of our universe, but in his ability to communicate it with masterful simplicity

can't go wrong with Feynman. He kept the thickness just right to make sure the transmission coefficient is 100%.

Foreword, by Leonard Mautner
Preface, by Ralph Leighton
Acknowledgment

--QED: The Strange Theory of Light and Matter

Index

Why do I do this to myself?

Es fascinante ver cómo algo tan difícil lo entienden y teorizan de una manera tan sencilla y elegante. Una obra maestra de Richard feynman, tanto la teoría como la manera de explicarla.