Asked if he had ever known Isaac Newton to laugh, one of the luminary’s Cambridge contemporaries responded that he had seen Newton betray amusement—once in 30 years.

Self-described “itinerant math historian” William Dunham elicited a much higher frequency of laughter on the chilly evening of January 28, when he treated a packed MAA Carriage House to highlights culled from Newton’s 3,000-page correspondence, put together by Cambridge University Press in a seven-volume collection.

In his NSA-funded Distinguished Lecture, Dunham excerpted for his audience letters from Newton’s years as a student and professor at Cambridge, from his time working at the Royal Mint in London, and from the “priority dispute” over whether he or Leibniz deserved credit for the calculus. Dunham turned at the end of his talk to the letter containing Newton’s famous “shoulders of giants” line, relating how he spent half an hour communing with the parchment in a Philadelphia library.

Dunham painted a picture of a prickly Newton, who, at 19, scolded a friend for getting drunk; wished death upon the philosopher John Locke for, Newton alleged, trying to “embroil” him with women; and mercilessly meted out justice to those who dared counterfeit coinage.

Though his surliness certainly helped to limit it, Newton circumscribed his social life intentionally. Often so absorbed in his work that he forwent food and personal hygiene—“It was said that his cat grew fat eating Isaac’s untouched meals,” Dunham reported—Newton regarded interpersonal relationships as potential distractions from his scholarly pursuits.

So, as Dunham told it, there was Newton, charting the course of modern science, alone in his room, serving sometimes as his own experimental subject. Dunham read from a letter in which Newton described the aftermath of staring at the sun (to see what the effect would be, naturally).

“By keeping in ye dark & imploying my mind about other things,” wrote the young Newton, “I began in three or four days to have some use of my eyes again.”

Such curiosity, intensity, and willingness to prioritize the quest for knowledge over personal comfort, Dunham implied, explain the magnitude of Newton’s scientific accomplishments. Along, of course, with what must have been a prodigious intellect.

“He has an IQ that’s three digits, four digits, five digits, who knows,” Dunham said. “He’s very smart.”

Newton’s most famous words, though, don’t show him lording his intelligence over anyone. Instead, Newton graciously acknowledged his reliance on the work of his predecessors. The storied sentence appears in a letter to Robert Hooke and followed recognition of contributions made by Hooke and René Descartes.

“If I have seen further,” Newton wrote, “it is by standing on the shoulders of Giants.”

Surprised to learn that the “shoulders of giants” letter belongs to the Simon Gratz autograph collection housed at the Historical Society of Pennsylvania, Dunham went to Philadelphia to see it. A librarian delivered the document—the original parchment, the original ink, touched by Newton’s own hand—to him in a manila folder.

“It was awesome,” Dunham said, displaying on the projection screen a photocopy of the letter.

Besides a mental image of the sentence Dunham called “the most famous line in the history of science,” Dunham’s listeners left the Carriage House with insight into Newton’s mathematical methods. Dunham included in his lecture an account of Newton's generalized binomial theorem and illustrated its use in approximating the cube root of 140 in a remarkably quick and accurate fashion. As Newton put it, "... extractions of roots are much shortened by this theorem."

Dunham also used his discussion of the binomial theorem—and the bits of notation it necessitated—to introduce one of his talk’s many laugh lines.

“If you know math,” Dunham quipped about 4!, “you see this and you say ‘four factorial,’ and if you don’t, you see this and say ‘FOUR!’”

And what was it that made the seemingly sour Newton chuckle that lone time at Cambridge?

“Professor Newton,” someone said, approaching the undisputed genius, book in hand. “This is Euclid’s *Elements*. Is there anything good in this?” —*Katharine Merow*

Watch a short version of the lecture or a full-length slidecast on YouTube.

Listen to an interview with William Dunham and MAA Director of Publications Ivars Peterson (mp3)

This MAA Distinguished Lecture was funded by the National Security Agency.