I am a retired engineer and read

*QED*, a book about Quantum Electro Dynamics (QED), several years ago and in trying to explain light reflection to a friend I discovered that I was not certain about my ideas on this matter. I do not want any complicated explanation of my error, if there is one, but can someone comment on my understanding of this matter?

I said to my friend that when a photon strikes the surface of an object that it is possible that the photon will strike an electron and in doing so will give up its energy to the electron which will in turn go to a higher energy level orbit. Later the electron will return to its ‘comfort’ level and in doing so will emit a photon from the atom.

This photon emitted from the atom will then go in any random direction but that if we add up the little arrows of probability we will discover that they add up to give us the impression that the photon of light is striking the surface and reflecting from that surface to my eye just as we all learned about the “angle of incidence is equal to the angle of reflection”.

“Richard Feynman based his version of quantum mechanics on the concept of "path integral". He proposed that the transition probability amplitude be calculated by summing contributions from each alternative space-time trajectory of the particles with specific phase factors. From this approach Feynman derived a graphical representation of the amplitudes of the QED, which made the theory much easier to handle. In “Feynman graphs” photons and electrons are pictorially given as lines in a space-time diagram. Interactions with exchange of energy-momentum and other properties occur in such space-time points, where particle lines meet. Feynman graphs are nowadays the standard method used to calculate theoretical predictions.

“The rules of the game are what we mean by fundamental physics.” This is Richard Feynman speaking and is quoted in his most remarkable book

*QED: The Strange Theory of Light and Matter*.

This book is a masterful exposition by a master teacher and scientist of quantum mechanics; aimed not at teaching students to do calculations, but at teaching them to understand what's going on behind calculations. Reading this book helps students avoid "a false sophistication which emphasizes technique rather than understanding." Most important, in my estimation, is that it is a book that any lay person can read, understand and enjoy. It will give the rugged individual--undaunted by preconceived notions--an opportunity to appreciate the mysteries and marvels of modern physics.

Feynman, in my opinion as well as many others, is a master scientist, wonderful human being, and most of all a master teacher.

**There is a layering quality in book publishing that works marvelously for the lay reader. Such individuals as Kant, Einstein, and Darwin write books explaining their original thoughts. A second layer of authors condense and clarify the thoughts of these original thinkers into a form more accessible to the learning student seeking to join the ranks of the experts. Then there is a third level where a person with fine writing skills takes this material and writes a book that is accurate, polished, and readable for the person looking to understand the general aspects of a domain of knowledge without too many complications.**

Richard Feynman is one of those rare creatures who fit all three levels of authorship. Most important to us, who wish to understand without too many complications, Feynman has written a book “QED”, which makes it possible for us to accomplish this task with much pleasure and awe.

Richard Feynman, now deceased, was a theoretical physicist and professor of physics at MIT gave to his students the following description of what physics is all about:

“We can imagine that this complicated array of moving things which constitutes “the world” is something like a great chess game being played by the gods, and we are observers of the game. We do not know what the rules of the game are; all we are allowed to do is to watch the playing. Of course, if we watch long enough, we may eventually catch on to a few of the rules. The rules of the game are what we mean by fundamental physics. Even if we know every rule, however…what we really can explain in terms of those rules is very limited, because almost all situations are so enormously complicated that we cannot follow the plays of the game using the rules, much less tell what is going to happen next. We must, therefore, limit ourselves to the more basic question of the rules of the game. If we know the rules, we consider that we “understand” the world.”

The natural sciences, especially physics, have been very successful at learning the rules of the game. Our didactic (teaching by telling) educational system has been very successful at teaching these rules to their students. The students have been very successful at using these rules and the algorithms and paradigms developed from these rules in developing the high tech economy that we have.

A small, elementary book based on popular lectures by Feynman, can be recommended: "QED. The Strange Theory of Light and Matter" by Richard Feynman (Princeton University Press, 1985), in which Feynman gives the essence of his version of QED in simple language and elegant manner, even describing how the laws of geometrical optics can be derived from the QED theory.”

The Dual Nature of Light as Reflected in the Nobel Archives

**I challenge the student of QM to use their knowledge to help DickandJane to gain some comprehension of this matter. They would have to convert their knowledge to a form that is comprehensible to anyone willing to work hard to comprehend the fundamental aspects of QM. You could place your essay about this matter on various Internet discussion forms and help the lay person to develop some fundamental comprehension of this very important science.**