The above quote is widely considered to be one of the greatest quotes about science by one of the greatest scientists in history. What is less known is that it was probably a petty insult given by one of the greatest jerks in the history of science.
It’s a testimony to the sort of person that Newton was that most people don’t even know that the quote was part of a letter written to Robert Hooke, who should be known as one of the most important figures in science (he is, but not so much in pop culture), and who would be were it not for Newton using his influence and authority (after the death of Hooke) to downplay/expunge the role Hooke played in the birth of modern science.
The reason that Newton bore such a grudge against Hooke is that when Newton published his work on optics he failed to acknowledge that he had been influenced heavily by the work Hooke himself had previously done. Hooke, being a man who was extremely considerate of giving others credit where credit was due, was not happy with not being given the recognition he deserved.
When Newton was made aware of Hooke’s objection (by an enemy of Hooke who exaggerated the complaint) he was insulted at the implication that his genius relied in some way on the work of Hooke, whom Newton viewed (as he did with pretty much everyone) as his lesser.
After a four year feud, the Royal Society made arrangements for the two men to publicly reconcile in order to preserve the good reputation of the organization. John Gribbin explains the rest in his excellent history of science The Scientists
Hooke’s letter to Newton seems to bear the genuine stamp of his personality, always ready to argue about science in a friendly way (preferably among a few companions in one of the fashionable coffee houses), but really only interested in the truth:After this affair, Newton waited 30 years to publish Opticks until Hooke died, at which point Newton no longer had to worry about Hooke reminding anyone of his own pioneering work in the subject.I judge you have gone farther in that affair [the study of light] than I did … I believe the subject cannot meet with a fitter and more able person to enquire into it than yourself, who are in every way fitted to complete, rectify, and reform what were the sentiments of my younger studies, which I designed to have done somewhat myself, if my other more troublesome employments would have permitted, though I am sufficiently sensible it would have been with abilities inferior to yours. Your design and mine, are, I suppose, both at the same thing, which is the discovery of truth, and I suppose we can both endure to hear objections, so as they come not in a manner of open hostility, and have minds equally inclined to yield to the plainest deductions of reason from experiment.There speaks a true scientist. Newton’s reply, although it could be interpreted as conciliatory, was totally out of character, and carries a subtext which is worth highlighting. After saying that ‘you defer too much to my ability’ (a remark Newton would never have made to anyone except under duress), he goes on with one of the most famous(and arguably most misunderstood) passages in science, usually interpreted as a humble admission of his own minor place in the history of science:What Des-Cartes did was a good step. You have added much in several ways, & especially in taking ye colours of think plates into philosophical consideration. If I have seen farther, it is by standing on the shoulders of Giants.John Faulkner, of the Lick Observatory in California, has suggested an interpretation of these remarks which flies in the face of the Newton legend, but closely matches Newton’s known character. The reference to Descartes is simply there to put Hooke in his place by suggesting that the priority Hooke claims actually belongs to Descartes. The second sentence patronizingly gives Hooke (the older and more established scientist, remember) a little credit. But the key phrase is the one about ‘standing on the shoulders of Giants’. Note the capital letter. Even granted the vagaries of spelling in the seventeenth-century, why should Newton choose to emphasize the word? Surely, because Hooke was a little man with a twisted back. The message Newton intended to convey is that although he may have borrowed from the Ancients, he has no need to steal ideas from a little man like Hooke, with the added implication that Hooke is a mental pygmy as well as a small man physically. The fact that the source of the expression predates Newton and was picked up by him for his own purposes only reinforces Faulkner’s compelling argument.