In existographies, Paul Dirac (53 BE-29 AE) (1902-1984 ACM) (IQ:190|#33) (RGM:201|1,350+) (Murray 4000:15|P) (PR:1,898|65AE / physicist:44) (Becker 160:94|3L) (Simmons 100:20) (CR:137) (LH:3) (TL:140|#71) was an English-born American physicist, noted for 
In 1926, Dirac worked out the general formulation of the exclusion principle. 
In 1928, Dirac derived a relativistic wave equation for the electron e⁻¹, using both quantum mechanics and relativity, from which he predicted the existence of electron anti-particle e⁺, i.e. antimatter particle; also co-predicted, independently, shortly thereafter, by Ettore Majorana (1928), and later discovered by Carl Anderson in 1932.
In 1930, Dirac published Principles of Quantum Mechanics, wherein he shows how to derive quantum mechanics from scratch, via 82 sections and 785 equations.
As a young man, Dirac was said to have been agnostic.
In 1923 to 1925, Dirac, in his early 20s, had become an atheist. During this period, Dirac exchanged letters with Isabel Whitehead, the mother of Henry Whitehead, one of Dirac’s friends at school, who was herself a mathematician and married to Henry Whitehead, a reverend and formerly been the Bishop of Madras, India. In these letters, Isabel tried to challenge Dirac’s atheism and or convert him to theism. Dirac's replies to these letters, however, have not been found, but as the attempts at conversion continued, they evidently had failed.
In 1927, at the fifth Solvay Conference in Brussels, while sitting around one evening at the hotel’s smoky lounge, some of the younger physicists were sitting around on chairs and sofas, among them Dirac, Werner Heisenberg, and Wolfgang Pauli, during the course of which, as recalled by Heisenberg, Dirac went off on rant about religion, triggered by a comment about Einstein’s habit of referring to god during discussions of fundamental physics:
- “If we are honest — and scientists have to be — we must admit that religion is a jumble of false assertions, with no basis in reality. The very idea of god is a product of the human imagination. It is quite understandable why primitive people, who were so much more exposed to the overpowering forces of nature than we are today, should have personified these forces in fear and trembling. But nowadays, when we understand so many natural processes, we have no need for such solutions. I can't for the life of me see how the postulate of an almighty god helps us in any way. What I do see is that this assumption leads to such unproductive questions as why god allows so much misery and injustice, the exploitation of the poor by the rich and all the other horrors He might have prevented. If religion is still being taught, it is by no means because its ideas still convince us, but simply because some of us want to keep the lower classes quiet. Quiet people are much easier to govern than clamorous and dissatisfied ones. They are also much easier to exploit. Religion is a kind of opium that allows a nation to lull itself into wishful dreams and so forget the injustices that are being perpetrated against the people. Hence, the close alliance between those two great political forces, the State and the Church. Both need the illusion that a kindly god rewards — in heaven if not on earth — all those who have not risen up against injustice, who have done their duty quietly and uncomplainingly. That is precisely why the honest assertion that god is a mere product of the human imagination is branded as the worst of all mortal sins.”
At the end of the rant, Pauli, who was raised Catholic, when asked what he thought, declared:
- “Well our friend Dirac, too, has a religion, and its guiding principle: There is no god and Dirac is his prophet.”
- — Wolfgang Pauli (1927), response to Dirac’s anti-religion rant
Everyone was said to have burst into laughter. Heisenberg later, supposedly, reported the story lucidly to Niels Bohr
In 1933, Dirac jotted the following note:
- "Any further assumption implied by belief in one's faith is inadmissible from the point of view of modern science, and should not be needed in a well-organized society."
- — Paul Dirac (1933), hand-written note; in reaction to Einstein's mentions of god and dice
This last Dirac quote, of note, along with the Pierre Laplace (1802) quote on god as an unneeded hypothesis, and the Wilhelm Ostwald (1909) quote on how the church now acknowledges science as the higher authority, were cited in the "religion | belief conflicts" section of the 17 Jun 2014 draft 41-page version of HCT, conceptualized, in Thims mind as a "triple citation" that he could use to dismiss god, in one hand wave, the way Laplace did in penning his Celestial Mechanics. The publication, however, stalled out at this point, after which, for the next five years or so, Thims had to grow and transform his mind from implicit atheism to explicit atheism, before HCT drafting could commence properly.
Later in his career, Dirac was said to have "softened" in his atheism, poking at the idea or notion that god could be a mathematician; the following are some statements to this effect:
- “Because god made it that way.”
- — Paul Dirac (c.1950), impatient response to student who asked why the universe obeyed certain rules
- “The theory describing reality best ought to be the most beautiful, because god made it that way.”
- — Paul Dirac (c.1950), commentary, supposedly, on the theories of Einstein, Schrodinger, and Bohr
This "because god made it that way" statement, is found on the Dirac tombstone, at Roselawn Cemetery, Tallahassee, Florida, as pictured adjacent, and shown below:
In 1963, Dirac, aged 61, was alluding to the idea that the equations of nature are constructed the way they are per reason that god is a mathematician:
- “You may wonder. Why is nature constructed along these lines? One can only answer that our present knowledge seems to show that nature is so constructed. We simply have to accept it. One could perhaps describe the situation by saying that god is a mathematician of a very high order, and he used very advanced mathematics in constructing the universe.”
In 1971, Dirac, aged 69, in respect to the question of the origin of life, argued that if the probability of starting life, owing to purely blind chance, was too small, than god would have to exist, so to start life:
- “It could be that it is extremely difficult to start life. It might be that it is so difficult to start a life that it has happened only once among all the planets... Let us consider, just as a conjecture, that the chance of life starting when we have got suitable physical conditions is 10−100. I don't have any logical reason for proposing this figure, I just want you to consider it as a possibility. Under those conditions ... it is almost certain that life would not have started. And I feel that under those conditions it will be necessary to assume the existence of a god to start off life. I would like, therefore, to set up this connection between the existence of a god and the physical laws: if physical laws are such that to start off life involves an excessively small chance so that it will not be reasonable to suppose that life would have started just by blind chance, then there must be a god, and such a god would probably be showing his influence in the quantum jumps which are taking place later on. On the other hand, if life can start very easily and does not need any divine influence, then I will say that there is no god.”
- — Paul Dirac (1971), “Does God Exist?”, Landau Meeting Conference
Alternatively, as he comments at the end, if life can start easily, then we can conclude: there is no god, as Pauli said about Dirac's views during the 1927 Solvay dialogue.
Quotes | On
The following are quotes on Dirac:
- “Where’s my Dirac?”
- — Albert Einstein (c.1935), frequent utterance of in respect to Dirac’s Principles of Quantum Mechanics, which Einstein regarded as a scientific “bible” so to say
- “I don’t know what all the fuss is about, Dirac did it all before me.”
- — Richard Feynman (c.1948) , Publication
Quotes | By
The following are quotes by Dirac:
- “It seems clear that the present quantum mechanics is not in its final form. Some further changes will be needed, just about as drastic as the changes made in passing from Bohr's orbit theory to quantum mechanics. Some day a new quantum mechanics, a relativistic one, will be discovered, in which we will not have these infinities occurring at all. It might very well be that the new quantum mechanics will have determinism in the way that Einstein wanted.”
- — Paul Dirac (1979), Publication
- Dirac dancing anecdote
- Heitler, Walter. (1936). Elementary Wave Mechanics: with Application to Quantum Chemistry (pg. 85). Oxford.
- Particle (subdomain) – Hmolpedia 2020.
- (a) Weigner, Eugene. (1942). Oral Examination of Feynamn's PhD thesis (co-examiner: John Wheeler); Examiners’ report is held in the Mudd Library, Princeton.
(b) Oppenheimer, Robert. (1980). Letters and Recollections (editors: A.K. Smith and C. Weinger) (pg. 269).
(c) Farmelo, Graham. (2009). The Strangest Man: the Hidden Life of Paul Dirac, Mystic of the Atom (pg. 234). Basic Books.
- Dalitz, R.H.; Peierls, Rudolf. (c.1985). “Paul Adriene Maurice Dirac, 8 Aug 1902-20 Oct 1984” (pdf) (pgs. 162-63), Biographical Memoirs. Royal Society.
- Farmelo, Graham. (2009). The Strangest Man: the Hidden Life of Paul Dirac (pdf) (Dirac the prophet, pg.138; Whitehead and atheism, pdf pg. 153). Basic Books.
- Heisenberg, Werner. (1971). Physics and Beyond: Encounters and Conversations (pgs. 85-86). Harper.
- Paul quote – QuoteFancy.com.
- Pais, Abraham. (1991). Niels Bohr’s Times: In Physics, Philosophy, and Polity (pg. 320; god, 5+ pgs). Oxford.
- Dirac tomb – Wikipedia.
- Atiyah, M. (1988). “Concluding Remarks”, in: Differential Geometry Methods in Theoretical Practice (editors: K. Bleuler, M. Werner) (§:461-70, quote, pg. 467). Springer.
- Dirac, Paul. (1963), “The Evolution of the Physicist’s Picture of Nature” (pg. 53), Scientific American, 208(5):43-53, May.
- Kragh, Helge. (1990). Dirac: a Scientific Biography (pgs. 256-57). Publisher.
- Author. (1982). “The Early Years of Relativity”, in: Albert Einstein: Historical and Cultural Perspectives: The Centennial Symposium in Jerusalem (editors: Gerald James Holton and Yehuda Elkana) (pg. 85). Princeton University Press.
- Anon. (2021). “Dirac age 26  predicts the anti-particle e⁺” (YT), Human Chemistry 101, Apr 30.
- Paul Dirac – Hmolpedia 2020.