Editing Paul Dirac (section)

===Personality===
[[File:Clara Ewald - Paul Dirac.jpg|thumb|upright|Portrait of Paul Dirac by [[Clara Ewald]], 1939]]
Dirac was regarded by his friends and colleagues as unusual in character. In a 1926 letter to [[Paul Ehrenfest]], [[Albert Einstein]] wrote of a Dirac paper, "I am toiling over Dirac. This balancing on the dizzying path between genius and madness is awful." In another letter concerning the [[Compton scattering|Compton effect]] he wrote, "I don't understand the details of Dirac at all."<ref>{{harvnb|Kragh|1990|p=82]}}  "Dirac verstehe ich im Einzelnen überhaupt nicht (Compton-Effekt)"</ref>
Dirac was known among his colleagues for his precise and taciturn nature. His colleagues in Cambridge jokingly defined a unit called a "dirac", which was one word per hour.<ref>{{harvnb|Farmelo|2009|p=89}}</ref> When [[Niels Bohr]] complained that he did not know how to finish a sentence in a scientific article he was writing, Dirac replied, "I was taught at school never to start a sentence without knowing the end of it."<ref name="standy">{{cite web |url=http://www-history.mcs.st-and.ac.uk/Printonly/Dirac.html |title=Paul Adrien Maurice Dirac |publisher=University of St. Andrews |access-date=4 April 2013}}</ref> He criticised the physicist [[J. Robert Oppenheimer]]'s interest in poetry: "The aim of science is to make difficult things understandable in a simpler way; the aim of poetry is to state simple things in an incomprehensible way. The two are incompatible."<ref>{{harvnb|Mehra|1972|pp=[https://books.google.com/books?id=CpJiqUFkHGoC&pg=PA17 17–59]}}</ref> Bohr called Dirac "a complete logical genius" and also the "strangest man" who had ever visited his Institute.{{sfnp| Farmelo| 2009| p=120}}

Dirac himself wrote in his diary during his postgraduate years that he concentrated solely on his research, and stopped only on Sunday when he took long strolls alone.<ref>{{harvnb|Kragh|1990|p=17}}</ref>

An anecdote recounted in a review of the 2009 biography tells of [[Werner Heisenberg]] and Dirac sailing on an ocean liner to a conference in Japan in August 1929. "Both still in their twenties, and unmarried, they made an odd couple. Heisenberg was a ladies' man who constantly flirted and danced, while Dirac—'an Edwardian geek', as biographer [[Graham Farmelo]] puts it—suffered agonies if forced into any kind of socializing or small talk. 'Why do you dance?' Dirac asked his companion. 'When there are nice girls, it is a pleasure,' Heisenberg replied. Dirac pondered this notion, then blurted out: 'But, Heisenberg, how do you know beforehand that the girls are nice?{{' "}}<ref name="mckie">{{cite web |url=https://www.theguardian.com/books/2009/feb/01/strangest-man-paul-dirac-review |title=Anti-matter and madness |last1=McKie |first1=Rob |date=1 February 2009 |work=The Guardian |access-date=4 April 2013}}</ref>

Margit Dirac told both [[George Gamow]] and Anton Capri in the 1960s that her husband had said to a house visitor, "Allow me to present Wigner's sister, who is now my wife."<ref>{{harvnb|Gamow|1966|p=121}}</ref><ref>{{harvnb|Capri|2007|p=148}}</ref>

[[File:Paul Dirac and Richard Feynman at Jabłonna 1962.png|thumb|Paul Dirac and Richard Feynman at Jabłonna, Poland. July 1962.]]
Another story told of Dirac is that when he first met the young [[Richard Feynman]] at a conference, he said after a long silence, "I have an equation. Do you have one too?"<ref>{{harvnb|Zee|2010|p=105}}</ref>

After he presented a lecture at a conference, one colleague raised his hand and said: "I don't understand the equation on the top-right-hand corner of the blackboard". After a long silence, the moderator asked Dirac if he wanted to answer the question, to which Dirac replied: "That was not a question, it was a comment."<ref>{{cite news | url=https://www.theglobeandmail.com/arts/books-and-media/review-the-strangest-man-by-graham-farmelo/article4289494/ | title=A quantum leap into oddness | first=Chet | last=Raymo | newspaper=[[The Globe and Mail]] | date=17 October 2009}} (Review of Farmelo's ''The Strangest Man''.)</ref><ref>{{harvnb|Farmelo|2009|pp=161–162}}, who attributes the story to [[Niels Bohr]].</ref>

Dirac was also noted for his personal modesty. He called the equation for the [[time evolution]] of a quantum-mechanical operator, which he was the first to write down, the "Heisenberg equation of motion". Most physicists speak of [[Fermi–Dirac statistics]] for half-integer-spin particles ([[fermions]]) and [[Bose–Einstein statistics]] for integer-spin particles ([[bosons]]). While lecturing later in life, Dirac always insisted on calling the former "Fermi statistics". He referred to the latter as "Bose statistics" for reasons, he explained, of "symmetry".<ref>{{cite book|last1=Mehra|first1=Jagdish|last2=Rechenberg|first2=Helmut|author-link1=Jagdish Mehra |author-link2=Helmut Rechenberg |title=The Historical Development of Quantum Theory|year=2001|publisher=Springer Science & Business Media|isbn=9780387951805|page=746|url=https://books.google.com/books?id=-pL56OcVubgC&q=Paul+Dirac+Einstein+statistics+Symmetry&pg=PA746}}</ref>