¹ May, Henry F.: The Enlightenment in America (New York and London, 1976), p. 25.Google Scholar

² A point too often overlooked by commentators who have tended to read the Essay Concerning Human Understanding as a product, albeit an off-shoot, of Newton's work. For further discussion on this see Rogers, G. A. J., ‘Locke's Essay and Newton's Principia ’, Journal of the History of Ideas, xxxix 04, 1978.Google Scholar

³ Newton suffered a severe mental disturbance in 1693 which led him to abruptly terminate his relationship with Samuel Pepys and to accuse Locke of endeavouring to embroil him with women, and of being a Hobbist. Cf. Manuel, Frank E. A Portrait of Isaac Newton (London and New York, 1968), p. 213 ff.Google Scholar

⁴ For some discussion of this see Rogers, G. A. J., ‘Locke, Newton, and the Cambridge Platonists on Innate Ideas’, Journal of the History of Ideas, XL 04, 1979.Google Scholar

⁵ There is as yet no proper study of their theological connections but there are pertinent discussions in McLachlan, H.: The Religious Opinions of Milton, Locke and Newton (Manchester, 1941)Google Scholar and Manuel, Frank E. The Religion of Isaac Newton (Oxford, 1974).Google Scholar

⁶ Newton's political views, including the rationale of political power, appear to have been very similar to Locke's. See here Newton's letter to the Vice-Chancellor of Cambridge University, when Newton, as Member of Parliament for the University, advised that the oaths to be taken to the new monarch William III were legal. The Correspondence of Isaac Newton (Cambridge, 1959–1960), III, pp. 12–13 Google Scholar, hereafter cited as Correspondence. See also More, L. T.: Isaac Newton. A Biography (London, 1934), ch. x.Google Scholar

⁷ Though basic, these facts have been too rarely heeded by commentators. On this see Rogers, cited in Note 2 above.

⁸ We know this from Locke's correspondence with Edward Clarke, to whom Locke sent his completed script in 1686. There is further support in a draft manuscript of the Essay (the third and latest extant draft, although only of the first and second books), which closely resembles the published work. For further discussion and references see Rogers (Note 2), Note 11.

⁹ The earliest extant reference to Newton, 's Principia Google Scholar in Locke's manuscripts is a series of notes dated September 1687. Bodleian Library MS, Locke C. 33, ff. 19–20.

¹⁰ In the Regulae Philosophandie at the beginning of Book III. The clarity of presentation is, however, deceptive. The interpretation of these Rules is full of difficulties. For recent discussions of some of these difficulties see Koyré, A.: Newtonian Studies (London, 1965)CrossRefGoogle Scholar, Ch. VI ‘Newton's Regulae Philosophandi’; McGuire, J. E. ‘Transmutation and Immutability: Newton's Doctrine of Physical Qualities’, Ambix, XIV, 1967 Google Scholar; McGuire, J. E.: ‘The Origin of Newton's Doctrine of Essential Qualities’, Centaurus, 12, 1968 Google Scholar; McGuire, J. E.: ‘Atoms and the Analogy of Nature: Newton's Third Rule of Philosophizing’ Studies in the History and Philosophy of Science, I, 1970 Google Scholar; Finocchiaro, M. A.: ‘Newton's Third Rule of Philosophizing: A Role for Logic in Historiography,’ Isis, 1974.CrossRefGoogle Scholar

¹¹ Locke's copy, which is in Trinity College, Cambridge, appears hardly to have been opened. It is true that Locke was already familiar with many of Newton's optical discoveries.

¹² Newton's more speculative thoughts were contained in the Queries added to Book III.

¹³ Whilst Newton's epistemology seems largely to have been empiricist, his ontology is very similar to that of the Cambridge Platonist, Henry More. His commitment to absolute space and time, for example, was a view shared with More, and may have been derived from him. There are also similarities in their conception of spirit as an active principle.

¹⁴ See, for example, the discussions in the following: Lohne, J. A.: ‘ Experimentum Crucis ’, Notes and Records of the Royal Society 23 (1968)Google Scholar; Westfall, R. S.: ‘Newton and the Fudge Factor’ Science 179 (1973)CrossRefGoogle ScholarPubMed; Whiteside, D. T., ‘Newton's Lunar Theory: From High Hope to Disenchentment’, Vistas in Astronomy, 19 (London, 1976).CrossRefGoogle Scholar

¹⁵ On the other side, he was often well aware that his own conjectures were not supported with sufficient evidence to justify their publication to the world, or even to be held as firm opinion by himself.

¹⁶ Both Locke and Newton probably owed as much to Descartes as they did to any thinker. Both also reacted critically to his stimulus and it is Cartesian views that both of their major works most strongly attack.

¹⁷ For discussions of Newton's speculations see J. E. McGuire: ‘Force, Active Principles and Newton's Invisible Realm’ Ambix 15, 1968; Westfall, R. S.: Force in Newton's Physics. The Science of Dynamics in the Seventeenth Century (London, 1971)Google Scholar, ch. VII, cf. also Query 28 of Newton, 's Opticks.Google Scholar

¹⁸ Locke became deeply interested in both medicine and chemistry whilst still an undergraduate, as his notebooks for that period testify. For a survey of his activities see Dewhurst, Kenneth: John Locke (1632–1704) Physician and Philosopher. A Medical Biography (London, 1963), ch. I.Google Scholar

¹⁹ See An Essay Concerning Human Understanding, II. I. 1–5.Google Scholar All quotations will be taken from the Clarendon Edition of the Works of John Locke, edited by Nidditch, Peter H. (Oxford, 1975).Google Scholar This edition is based on the fourth edition of the Essay, and will be cited by Book, Chapter and Section numbers. Unless otherwise cited all Locke references are to the Essay in this edition.

²⁰ I. IV. 24.

²¹ I. IV. 22.

²² I. IV. 18.

²³ II. I. 9.

²⁴ II. I. 18.

²⁵ II. I. 21.

²⁶ I. I. 2.

²⁷ For discussion of this draft Rule see Koyré op. cit. and Cohen, I. B.: Introduction to Newton's Principia (Cambridge, 1971), pp. 30–31.CrossRefGoogle Scholar

²⁸ University Library, Cambridge (U.L.C.) MS, Add. 3965.13, f. 419r.

²⁹ II. VIII. 4.

³⁰ II. VIII. 11.

³¹ II. VIII. 13.

³² See A. D. Woozley's Introduction to his abridged edition of the Essay, Fontana Library (London, 1964), pp. 26–8Google Scholar, and Yolton, John W.: Locke and the Compass of Human Understanding (Cambridge, 1970), p. 134.Google Scholar Locke's An Examination of P. Malebranche's Opinion of Seeing All Things in God was posthumously published in 1706.

³³ IV. IV. 3.

³⁴ IV. IV. 4.

³⁶ IV. XI 3.

³⁶ Opticks (4th edition, London, 1730 Dover reprint, 1952), p. 15.Google Scholar

³⁷ Newton, to Briggs, William, 09 12 1682.Google Scholar Correspondence II, p. 383.Google Scholar

³⁸ U.L.C. Add MS. 3970.9 f. 62 IV.

³⁹ U.L.C. Add MS. 3970.9 f. 620r.

⁴⁰ An example taken from a list of phenomena in Newton's manuscripts, now published in Unpublished Scientific Papers of Isaac Newton, ed. by Hall, A. R. and Hall, Marie Boas (Cambridge, 1962), pp. 378–85.Google Scholar

⁴¹ From Newton's paper to the Royal Society, published in the Philosophical Transactions of the Royal Society No. 80 (1672).Google Scholar Reprinted in Isaac Newton's Papers and Letters on Natural Philosophy, ed. by Cohen, I. B. (Cambridge, 1958), p. 47.Google Scholar

⁴² As well as the letter already quoted see also the paper published in Brewster, David's Memoirs of Sir Isaac Newton (2nd edition, Edinburgh, 1860), I, pp. 395–8.Google Scholar

⁴³ For a description of this notebook see Hall, A. R.: ‘Sir Isaac Newton's Note-Book’, Cambridge Historical Journal, 9, 1948, pp. 239–50.CrossRefGoogle Scholar The notebook's entries were made between 1661 and 1665, when Newton was an undergraduate.

⁴⁴ U.L.C. Add MS. 3996, f. 130.

⁴⁵ Ibid. f. 102.

⁴⁶ Ibid. f. 131.

⁴⁷ Ibid. f. 130.

⁴⁸ Hall, and Hall, (op. cit. Note 40), p. 138.CrossRefGoogle Scholar

⁴⁹ Principles of Philosophy Part II, Principle V.

⁵⁰ U.L.C. Add MS. 3965, ff. 361–2. Published in Hall, and Hall, (op. cit. Note 40), p. 361.CrossRefGoogle Scholar

⁵¹ II. XXIII. 30.

⁵² Opticks, ed. cit., p. 399.Google Scholar

⁵³ Correspondence III, pp. 253–4½.Google Scholar

⁵⁴ U.L.C. Add MS. 3970.9, f. 619.

⁵⁵ Newton's claim was made to Pierre Coste, as reported in a footnote to Goste's French translation of Locke, 's Essay (3rd edition, Amsterdam, 1735, p. 521).Google Scholar The footnote refers to Essay, IV, X, 18.Google Scholar On this see Koyre, : Newtonian Studies, p. 92.Google Scholar See also the remark of David Gregory: ‘Mr. G. Wren says that he is in possession of a method of explaining gravity mechanically. He smiles at Mr. Newton's belief that it does not occur by mechanical means, but was introduced originally by the Creator.’ Correspondence IV, p. 267.Google Scholar

⁵⁶ II. XXIII. 28.

⁵⁷ Some Thoughts Concerning Education, in The Educational Writings of John Locke, edited by Axtell, James L. (Cambridge, 1968), p. 305.Google Scholar

⁵⁸ Ibid. p. 306.

⁵⁹ II. I. 18.

⁶⁰ IV. XII. 12.

⁶¹ IV. XII. 13.

⁶² U.L.C. Add MS. 3970, f. 479.

⁶³ This ideal was expressed in a letter to Mersenne in 1640 thus: ‘I would think I knew nothing in Physics if I could only say how things could be, without proving that they could not be otherwise. This is perfectly possible once one has reduced everything to laws of mathematics; I think I can do it for the small area to which my knowledge extends. But I did not do it in my essays because I did not want to present my Principles there, and I do not yet see anything to persuade me to present them in future.’ Descartes, Philosophical Letters translated and edited by Kenny, Anthony (Oxford, 1970), pp. 70–71.Google Scholar The Principles were in fact published four years later.

⁶⁴ In a letter to Cotes, Roger. Correspondence, V, p. 397.Google Scholar See also the draft letter to Cotes, (pp. 398–9)Google Scholar:

Experimental Philosophy reduces Phaenomena to general Rules & looks upon the Rules to be general when they hold generally in Phaenomena. It is not enough to object that a contrary phaenomenon may happen but to make a legitimate objection, a contrary phenomenon must be actually produced. Hypothetical Philosophy consists in imaginary explications of things & imaginary arguments for or against such explications, or against the arguments of Experimental Philosophers founded upon Induction. The first sort of Philosophy is followed by me, the latter too much by Cartes, Leibniz & some others.

⁶⁵ Rule IV Regulae Philosophandi, Principia Book III. The translation is that in Andrew Motte's translation, revised by Cajori, Florian (Berkeley and Los Angeles, 1962), p. 400.Google Scholar

⁶⁶ Woolhouse, R. S. in his Locke's Philosophy of Science and Knowledge (Oxford, 1971)Google Scholar attributes rationalism to Locke, which he defines as the view ‘that in natural science we have to do with synthetically necessary propositions which are not by us knowable a priori’ (p. 25).Google Scholar

⁶⁷ IV. III. 29.

⁶⁸ On the voluntarist tradition in this context see Oakley, Francis: ‘Medieval Theories of Natural Law: William of Ockham and the Significance of the Voluntarist Tradition’, Natural Law Forum, 6, 1961.Google Scholar

⁶⁹ Locke expresses a similar position in his A Discourse of Miracles, published posthumously in 1706.

⁷⁰ Correspondence, III, p. 234.Google Scholar Newton, to Bentley, Richard, 1692.Google Scholar

⁷¹ Principia (ed. cit., Note 65), p. 546.Google Scholar