By: James Gleick, read in 2019

123 "'GRÜNBAUM: I want to say that there is a difference between a conscious thing and an unconscious thing. [FEYNMAN]: what is the difference?... It seemed to Feynman that a robust conception of "now" ought not to depend on murky notions of mentalism. The minds of humans are manifestations of physical law, too, he pointed out. Whatever hidden brain machinery created Grünbaum's coming into being must have to do with a correlation between events in two regions of space- - the one inside the cranium and the other elsewhere "on the space-time diagram." In theory one should be able to create a feeling of nowness in a sufficiently elaborate machine, said Mr. [Feynman]." This is a good starting point for speculating on the mechanism that explains my SG (Stylus Guy).

128 "[Herbert] Jehle asked Feynman what he was working on. Feynman explained and asked in turn whether Jehle knew of any application of the least-action principle in quantum mechanics.

Jehle certainly did. He pointed out that Feynman's own hero, Dirac, had published a paper on just that subject eight years before. The next day Jehle and Feynman looked at it together in the library. It was short. They found it, "The Lagrangian in Quantum Mechanics," in the bound volumes of Physikalische Zeitschrift der Sowjetunion, not the best-read of journals. Dirac had worked out the beginnings of a least-action approach in just the style Feynman was seeking, a way of treating the probability of a particle's entire path over time. Dirac considered only one detail, a piece of mathematics for carrying the wave function- - the packet of quantum-mechanical knowledge- - forward in time by an infinitesimal amount, a mere instant.

Infinitesimal time did not amount to much, but it was the starting point of the calculus. That limitation was not what troubled Feynman. As he looked over the few bound pages, he kept stopping at a single word: analogue. "A very simple quantum analogue, " Dirac had written. ". . . They have their classical analogues. . . . It is now easy to see what the quantum analogue of all this must be." What kind of word was that, Feynman wondered, in a paper on physics? If two expressions were analogous, did it mean they were equal?

No, Jehle, said- - surely Dirac had not meant that they were equal. Feynman found a blackboard and started working through the formulas. Jehle was right: they were not equal. So he tried adding a multiplication constant. Calculating more rapidly than Jehle could follow, he substituted terms, jumped from one equation to the next, and suddenly produced something extremely familiar: the Schroedinger equation. There was the link between Feynman's Lagrangian-style formulation and the standard wave function of quantum mechanics." Ask Dr. Dick about this.

255 "...time in physics had already departed from time in psychology - that nothing in the microscopic laws of physics seemed to mandate a distinction between past and future, and that Einstein had already ruined the notion of absolute time, independent of the observer. Yet Einstein had not imagined a particle's history reversing course and swerving back against the current. Feynman could only resort to an argument from utility: "It may prove useful in physics," he wrote, "to consider events in all of time at once and to imagine that we at each instant are only aware of those that lie behind us."" A clear suggestion that we should consider SG
336 "In sorting the various kinds of particle interactions, theorists had created a classification scheme with five distinct transformations of one wave function into another In one sense it was a classification of the characteristic algebraic techniques; in another, it was a classification of the types of virtual particles that arose in the interactions, according to their possible spins and parities. As shorthand, physicists used the labels S, T, V, A, and P, for scalar, tensor, vector, axial vector, and pseudoscalar." This suggests higher dimensions in which our manifold is embedded.
363 Feynman: "The ratchet and pawl works in only one direction because it has some ultimate contact with the rest of the universe. . . . Because we cool off the earth and get heat from the sun, the ratchets and pawls that we make can turn one way. . . . It cannot be completely understood until the mystery of the beginnings of the history of the universe are reduced still further from speculation to scientific understanding."
364 "...another request came in for a copy if the photograph - from a Swedish encyclopedia publisher who wished to "give a human approach to a presentation of the difficult matter that theoretical physics represent" - he exploded. "Dear Sir," he scrawled

"The fact that I beat a drum has nothing to do with the fact that I do theoretical physics. Theoretical physics is a human endeavor, one of the higher developments of human beings - and this perpetual desire to prove that people who do it are human by showing that they do other things that a few other humans do (like playing bongo drums) is insulting to me. I am human enough to tell you to go to hell."
364 Explanation
368 "He began with a void, no fields or waves, no concept of relativity, not even a notion of light itself, just a single particle obeying quantum mechanics' odd rules. Before Dyson's eyes he traveled back mathematically from the new physics, with its riddles of uncertainty and immeasurability, to the comforting exactitude of the previous century. He showed that Maxwell's field equations were not a foundation but a consequence of the new quantum mechanics."
371 "He believed in the primacy of doubt, not as a blemish upon our ability to know but as the essence of knowing. The alternative to uncertainty is authority, against which science had fought for centuries. "Great value of a satisfactory philosophy of ignorance, " he jotted on a sheet of notepaper one day.". . . teach how doubt is not to be feared but welcomed.""
383 "My desire to resign is merely a personal one; it is not meant as a protest of any kind. . . . My peculiarity is this: I find it psychologically very distasteful to judge people's "merit." So I cannot participate in the main activity of selecting people for membership. To be a member of a group, of which an important activity is to choose others deemed worthy of membership in that self-esteemed group, bothers me. . . . Maybe I don't explain it very well, but suffice to say that I am not happy as a member of a self-perpetuating honorary society." Feynman's explanation for resigning from the National Academy of Sciences.
387 "Murray Gell-Mann said, uncontroversially, that he and his colleagues had developed a theory that "works." He summed it up in one intricately crafted sentence (rather more refined than "All things are made of atoms . . . "): It is of course a Yang-Mills theory, based on color SU(3) and electroweak SU(2) x U(1), with three families of spin 1/2 leptons and quarks, their antiparticle, and some spinless Higgs bosons in doublets and antidoublets of the weak isotopic spin to break the electroweak group down to U1 of electromagnetism."
390 "Gell-Mann won the linguistic battle once again: his choice, a croaking nonsense word, was quark. (After the fact, he was able to tack on a literary antecedent when he found the phrase "Three quarks for Muster Mark" in Finnegans Wake, but the physicist's quark was pronounced from the beginning to rhyme with "cork.")"
399 "It will perhaps surprise most people...to discover that the symbol ∪ or ∩ representing union and intersection of sets . . . all the elaborate notation for sets that is given in these books, almost never appear in any writings in theoretical physics, in engineering, business, arithmetic, computer design, or other places where mathematics is being used."
403 "Feynman made an original effort in 1981 to solve this problem analytically in a toy model of two dimensions. Quantum chromodynamics...had become a theory of such internal complexity that usually even the fastest supercomputers could not generate specific predictions to compare with experiments. "QCD field theory with six flavors of quarks with three colors, each represented by a Dirac spinor of four components, and with eight four-vector gluons, is a quantum theory of amplitudes for configurations each of which is 104 numbers at each point in space and time," he wrote. "To visualize all this qualitatively is too difficult. So he tried removing a dimension. This turned out to be a blind alley, although the freshness of his approach kept the work on some theorists' reading lists long after they had passed by its conclusions."
425 "STS" stands for Space Transportation System.