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``On the shoulders of Giants''The last sentence below is one of Newton's most famous statements. It has been used to demonstrate his humilty and is repeated as a symbol of scientific progress. Nevertheless, some authors have asked if it was a veiled insult to Hooke, a man of ``crooked and low stature'', rather than a Giant, and these arguments are examined below (and I believe rejected.)
The image itself has been traced back to the twelfth century renaissance and a debate whether the ``moderns'' could advance further than the ``ancients'', despite the assumed decay of the world and men since the Classical period. Bernard of Chartres said the moderns could indeed see further because We are as dwarfs sitting on the shoulders of giants (Nos esse quasi nanos gigantum humeris insidientes.) A comprehensive study of the image has been made by Robert Merton who found twenty six other authors who used it between the time of Bernard and Newton.
The letter to Hooke was the result of Newton's An Hypothesis explaining the Properties of Light discoursed of in my severall Papers. (Corres I, pp362-83 or Norton pp12-34) The Hypothesis was sent to Henry Oldenburg, the secretary of the Royal Society, on 7th December 1675 and attempted to explain many phenomena in optics, electrics and gravity with a corpuscular theory of light and ``an æthereall Medium much of the same constitution with air, but far rarer.'' Before discussing the letter to Hooke it is necessary to outline some contemporary optical theories.
Optical TheoriesPreviously Descartes had proposed that all space was permeated by an æther and that light was merely pressure waves (longitudinal vibrations) moving through this medium (in fact Descartes believed the æther was incompressible and so light propagated instantaneously. A theory of light similar to sound waves was only developed by Huygens in the 1670's.) Hooke introduced colours by suggesting that pulses were modified or ``confused'' as light crossed from one transparent material into another. Blue light was pulses in which the weakest part preceded and the strongest followed; in red light the strongest part led. Other colours were mixtures of blue and red light but white light was not ``confused'', not separated into weak and strong components and therefore fundamental.
Newton proposed that light was composed of particles, each with an inherent and unmodifiable colour. White light was a mixture of all the colours in the spectrum (or a rainbow) but could be separated into its constituents by refraction at the surface of a prism for example. He introduced an æther to account for the colours in thin plates or between plates of glass: the periodic patterns were the signature of vibrations in something and he suggested that the æther was excited by the particles of light and in turn affected their transmission at surfaces.
Newton to OldenburgWhen Newton's Hypothesis was read out at a Royal Society meeting in London on 16th December, Hooke stood up and said ``that the main of it was contained in his Micrographia, which Mr. Newton had only carried further in some particulars.'' This may refer specifically to the experiments with colours in thin plates which Hooke had described in his book. As Newton was in Cambridge, the meeting was reported to him by Oldenburg in a letter which has not survived.
Newton responded to this claim in a letter to Oldenburg on 21st December (Corres I, p404) and listed the components of Descartes', Hooke's and his own theories which were relevant - essentially saying that Hooke introduced the idea of confused pulses and applied the theory to the colours of thin plates. But the difference between Descartes' and Hookes' theories and Newton's was much greater: since Newton proposed particles of light with vibrations in the æther only influencing their motion. In a crucial passage Newton says ``But it may be he means yt I have made use of his Observations & of some I did; ... ; & that of plated bodies exhibiting colours, a Phænomenon for ye notice of wch I thank him: But he left me to find out & make such experiments about it as might inform me of ye manner of ye production of those colours, to ground an Hypothesis on''.
So even in a letter to Hooke's enemy, in which Newton is defending himself, he acknowledges his debt for the phenomenon of thin plates.
Hooke to NewtonThe letter to Oldenburg was read out at the Royal Society on 30th December 1675. Hooke wrote directly to Newton on 20th January 1676 saying he suspected that ``you might have been some way or other misinformed concerning me''. Hooke had been in a dispute with Oldenburg for some time and suspected someone's ``sinister practices'' had misled Newton. He goes on to say that he did not ``approve of contention or feuding and proving in print'' and that he judged ``you have gone farther in that affair much than I did'' and ``I believe the subject cannot meet with a fitter and more able person to inquire into it than yourself, who are every way accomplished to compleat, rectify and reform what were the sentiments of my younger studies, which I designed to have done somewhat at myself, if my other more troublesome employments would have permitted, though I am sufficiently sensible it would have been with abilities much inferior to yours.'' (My italics.)
The clause in italics is true. Where Hooke had made a qualitative study of the colours of thin plates, Newton had designed experiments which measured the distances between glass surfaces to hundred thousandths of an inch - unprecedented achievement in seventeenth century science. It seems likely that in the face of such success, Hooke showed apprehension and respect for this new competitor rather than insincere praise.
Hooke then suggests that they ``correspond about such matters by private letter'' and that having read the Hypothesis himself, he will ``send you freely my objections, if I have any, or my concurrences, if I am convinced, which is the more likely.'' In the most direct statement of his intentions, he says if ``they be put together by the ears of other's hands and incentives, it will produce rather ill concomitant heat which serves for no other use but kindle cole. Sr I hope you will pardon this plainness''. The phrase ``kindle cole'' also appeared in Hooke's diary entry for the letter on the same day: ``Wrot letter to Mr Newton about Oldenburg kindle Cole.'' (Westfall quotes a comment by Oliver Cromwell in Parliament on 25 Jan 1658: ``to kindle coals to disturb others'', Never at Rest p273 n105)
In this way Hooke acknowledged Newton's ability and greater progress in the subject, while maintaining his claim to have began the study of colours in thin plates - the only claim Hooke insisted on in the letter and something Newton had himself admitted to Oldenburg.
Newton to HookeFinally we come to Newton's reply of 5th February 1676. He says Hooke has ``done what becomes a true Philosophical spirit'' and that ``there is nothing wch I desire to avoyde in matters of Philosophy more than contention, nor any kind of contention more than one in print.'' In response to Hooke's compliment that Newton was the fittest person to continue his investigations, he begins:
The tone is certainly conciliatory and significantly Newton praises Hooke for beginning and publishing the study of phenomena of thin plates, just as he did in the letter to Oldenburg on 21st December 1675, and just as Hooke insisted on in his letter to Newton (and remember this is the only claim Hooke makes in that letter.) It seems that all three letters agree over this issue and both Newton and Hooke imply the other has achieved more than they claim credit for. This flatly contradicts suggestions that they are damning each other with faint praise or implying the other's work is unimportant.
In context, it seems that the ``Giants'' can only be Descartes and Hooke. This is certainly the implication of this passage at face value and Newton mentions no one else in the corresponding passage in his letter to Oldenburg. I find the idea that the word ``Giants'' is meant to exclude Hooke on the grounds of his height implausible (It is a plural after all!)
It has also been suggested that ``Giants'' is meant as cruel irony or slight. It is certainly an exageration but I see no evidence that this is intended as sarcasm rather than an extravagant compliment. Westfall dismissed this with two of his distinctive comments: ``As Newton said once before in regard to Hooke, he avoided oblique thrusts. When he attacked, he lowered his head and charged'' (Never at Rest p274 n106) referring to Newton's letter to Oldenburg on 11th June 1672, again in response to criticisms from Hooke. He said he had avoided ``oblique & glancing expressions'' to which Westfall says ``That is, he employed the broadsword instead of the rapier.'' (Never at Rest p247) Whatever else one says about the ``Giants'' letter of 5th February 1676, obvious slashes from Newton's broadsword are not visible.
After accepting Hooke's offer of a private correspondence, Newton initiates it by repeating a verbal offer to observe the transit of a star near the zenith, in Cambridge. He even weaves it into the conventional ending of a letter by saying ``If therefore you continue in ye mind to have it observed, you may by sending your directions command Your humble Servant Is. Newton.''
Despite this, no reply from Hooke has been found. Hall calls this ``astonishing insensitivity'' (Hall p139) but presumably Newton, deep in alchemy and theology by this time, was less concerned.
Accounts of the ``Giants'' letter
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