The Only Two Times Isaac Newton Supposedly Laughed In His Life

Isaac Newton will forever be considered an iconic physicist, the British genius who penned the revered "Philosophiae Naturalis Principia Mathematica" (Mathematical Principles of Natural Philosophy) in 1687, Biography reports. There's no denying the intellect of Newton the scientist, but Newton the person was rather more of an enigma, especially during his childhood.

National Geographic states that Newton was born in England in January 1643 and soon grew to be a thoughtful and intellectual child. Young Newton loved making models, including a little working mill he created (a hamster in a wheel enabled it to work). Such pursuits suggest that he was just as serious and science-oriented as a child, and he is said to have only laughed out loud twice in his life.

According to Henry P. Macomber's paper "Glimpses of the Human Side of Sir Isaac Newton," the great scientist worked with secretary Humphrey Newton during one of the busier periods of his life. Per The Newton Project, William Stukeley said he only witnessed only one laugh from the genius. It came about because Isaac had loaned an acquaintance a copy of "Euclid" and later asked them their thoughts on the book. The friend responded by asking why studying such things would ever be of any help to them, "upon which," wrote William Stukeley in a letter to Richard Mead, "Sir Isaac was very merry."

The second recorded laugh of Isaac Newton's life came about in similar circumstances. John Conduitt, per The New Atlantis, was Newton's nephew-in-law. Conduitt was intrigued by Newton's notions of space and the universe and was apparently privy to several of Newton's brilliant thoughts on the subject. On one occasion, the two men were discussing the "Principia" and, more specifically, Newton's concept of "fixed stars" and comets. Conduitt asked why Newton wasn't more forthcoming with his thoughts about the sun (something a little more local, astronomically speaking). Per The New Atlantis, Newton's response was "that [the sun] concerned us more and laughing added he had said enough for people to know his meaning."

Of course, it's essentially impossible that these were the only two times Newton laughed in his whole life. In fact, per The Newton Project, William Stukeley's "Memoirs of Sir Isaac Newton's Life" reveals, "according to my own observation, tho' Sir Isaac was of a very serious ... frame of mind, I have often seen him laugh ... in company ... he was easily made to smile, if not to laugh." Stukeley's words paint a picture of Newton's fantastic wit and suggest he was much more than just a stuffy scientist.