1 The standard English translation of the correspondence, The Leibniz-Arnauld Correspondence, edited and translated by Mason, H. T. (Manchester: Manchester University Press, 1967)Google Scholar, has the pagination, Gerhardt (Die Philosophische Schriften von G. W. Leibniz, edited by Gerhardt, C. I., 7 vols., Berlin [1875–1890]; hereafter Gerhardt) as marginalia. In what follows, LA refers to the Mason edition, and the page references are to the marginal pagination. In some of the quotations I have followed Sleigh's suggestions concerning changes in translationGoogle Scholar.

2 Discourse on Metaphysics (hereafter DM), edited and translated by Lucas, Peter G. and Grint, Leslie (Manchester: Manchester University Press, 1953 [first printed 1846, written 1685–86]), Introduction, p. xv: printed 1846, written 1685–86]), Introduction, p. xv: “[Leibniz] sent to Arnauld in February 1686 not the Discourse itself but a list of the summaries [of sections]—an astonishingly ill-judged act, for the headings are only imperfectly intelligible by themselves and Arnauld could not conceivably have gained from them a proper understanding of the system.”Google Scholar

3 Leibniz to Des Bosses, May 26, 1712, Gerhardt 2.444, translated in Loemker, Leroy E., Gottfried Wilhelm Leibniz Philosophical Papers and Letters, 2nd ed. (Dordrecht: D. Reidel, 1969) (hereafter Loemker), p. 603Google Scholar.

4 And not only for Leibniz—all kinds of things were happening. Boyle was publishing his Free Inquiry into the Vulgarly receiv'd Notion of Nature, James II was passing briefly through the sovereignty of England, the weather in Europe was getting better after a series of very cold winters (but not too much better: it was a blizzard that gave Leibniz the enforced leisure to write the Discourse), Dryden was writing The Hind and the Panther, Halley was producing the first map of the winds of the world and Newton was finishing the Principia. Bliss was it in that dawn to be alive, but to be a philosopher was very heaven! (It was not bliss unalloyed, however. The Turks and the Venetians were busily putting in place the conditions that would allow the firing of a single mortar shell to destroy the Parthenon in September of the following year.)

Incidentally, Loemker gives the date of A Free Inquiry into the Vulgarly re-ceiv'd Notion of Nature as 1682 (Loemker, p. 498), and adds, “Robert Boyle's Tractatus de ipsa natura (1688) repeated the mechanical conception of nature which he formulated in his Free Inquiry of 1682.” (Loemker, p. 508 n.l). But in (Loemker, p. 508 n.l). But in fact (a) the Notion of Nature, though it was mostly written about 20 years earlier, and though its Preface is dated September 1682, was not published until January 1686, and (b) the Tractatus de ipsa natura is simply the Latin translation of the Notion of Nature. Thus Leibniz would not at this stage have had, as Loemker's dating suggests he could have, any knowledge of Boyle's treatise on nature. For further details seeGoogle ScholarFulton, John F., A Bibliography of the Honourable Robert Boyle, 2nd ed. (Oxford: Clarendon Press, 1961), pp. 112–15, andGoogle ScholarSelected Philosophical Papers of Robert Boyle, edited by Stewart, M. A. (Manchester: Manchester University Press, 1979), p. xxiiGoogle Scholar.

5 Kipling, Rudyard, “In the Nolithic Age” Rudyard Kipling's Verse: Inclusive Edition 1885–1926 (Garden City, NY: Doubleday, Doran, 1931), p. 396Google Scholar.

6 Dryden, John, “Hind and the Panther,” The Poems of John Dryden, edited by Kinsley, James (Oxford: Clarendon Press, 1958), 3.389Google Scholar.

7 I am not suggesting that Sleigh is wrong to avoid psychohistory in this work—no one book can contain everything. Nor am I suggesting tha t he is wrong to avoid it altogether: even Kant could not complain at the development of one kind of historical talent at the expense of another. I do, though, think it would be a pity if everyone neglected it.

8 Vendler, Zeno, “Descartes' Exercises,” Canadian Journal of Philosophy, 19 (1989): 193–224. Vendler's provocative article goes into detail on this issue, but even on the surface there are relevant points as Leibniz noted: “the surface there are relevant points as Leibniz noted: “The argument for the existence of God taken from the concept of God was first discovered and stated o far as is known, by Anselm, archbishop of Canterbury.… It was frequently examined by various authors of the Scholastic theology and by Thomas Aquinas himself, from whom Descartes, who was no strangep knowledge, having studied with the Jesuits of La Fléche, seems to have borrowed it” (Animadversiones inpartem generalem Principiorum Cartesianorum, Gerhardt 4.358 and n., trans. Loemker, p. 386)CrossRefGoogle Scholar.

9 Cranston, Maurice, John Locke: A Biography (London: Longmans, Green, 1957), p. 353. Compare the following: “After Boyle's death, Newton conducted an allusive and inconclusive correspondence with one of Boyle's literary executors, John Locke… to whom Boyle had earlier written about his wish ‘to leave a kind of Hermetic legacy to the studious disciples of that art.’ Newton was clearly anxious to know more about this and about Boyle's ‘red earth.’ His own deep interest in alchemy was by then long established He must have known that Locke would not prove entirely unresponsive to his hints an d conjectures, for Locke too had for some time exhibited a real, if less intense, involvement in alchemical pursuits” (Google ScholarHoppen, K. T., “The Nature of the Early Royal Society,” British Journalfor the History of Science, 9 [1976]: 10–19, p. 13)Google ScholarPubMed.

10 See, e.g., Dobbs, Betty Jo, The Foundations of Newton's Alchemy or The Hunting of the Greene Lyon (Cambridge: Cambridge University Press, 1975) andGoogle ScholarThe Janus Faces of Genius: the Role of Alchemy in Newton's Thought (Cambridge: Cambridge University Press, 1991)Google Scholar.

11 George, Rolf, “The Lives of Kant,” Philosophy and Phenomenological Research, 47 (1986–1987): 485–500, p. 489. George has carried the discussion further in his paper “On Kant, Women, Sentimental Literature and Sensationist Epistemology,” delivered to the Canadian Philosophical Association meetings, Victoria, 1990, where he points out the way in which a popular but gross misunderstanding of Kant's life has led some commentators to a considerable misinterpretation of Kant's philosophical viewsCrossRefGoogle Scholar.

12 Feingold, , The Mathematician's Apprenticeship: Science, Universities and Society in England, 1560–1640 (Cambridge: Cambridge University Press, 1984), pp. 2–3. No doubt such an approach is passe among professional historians of science, but it still flourishes among the (comparatively) lay populace. For a striking example see the somewhat uncharacteristically wrong-headed account of Aristotle's place in the history of science byGoogle Scholar, Peter and Medawar, Jean in Aristotle to Zoos (Cambridge, MA: Harvard University Press, 1983)Google Scholar.

13 Feingold, Mordechai, The Mathematicians' Apprenticeship, pp. 2–3Google Scholar.

14 Trevor-Roper, Hugh, Catholics, Anglicans and Puritans (London: Fontana, 1989), p. xiii. This stance is common among historians.Google ScholarLeeuwen, Thus Henry G. van in his excellent The Problem of Certainty in English Thought 1630–1690 (The Hague: Martinus Nijhoff, 1970)CrossRefGoogle Scholarwrites: “In examining the Rule of Faith controversy and the English Protestant solution to it, we shall not judge the theological merits of either the controversy or the solution to it. To do that would be to go beyond the scope of this study whose aim is to examine only the history of a particular theory in English religious and scientific thought” (p. 15)Google Scholar. Shapin, Similarly Steven and Schaffer, Simon in their Leviathan and the Air Pump: Hobbes, Buyle, and the Experimental Life (Princeton: Princeton University Press, 1985) explicitly abandon any attempt to decide upon the truth of the various matters they discuss, preferring rather to talk about “rejected and accepted knowledge” (p. 11)Google Scholar.

15 Bennett, Jonathan, Kant's Dialectic (Cambridge: Cambridge University Press, 1974), p. 6Google Scholar.

16 It is worth noting that this request would have sounded familiar to seventeenth-century ears, for it is precisely the one that the new experimental philosophers were wont to put to their scholastic opponents, transposed into a textual key. Tell us, they kept saying, the story in terms we can understand, give us an intelligible, i.e., a mechanical, account. As Boyle put it: “… to explicate a phenomenon being to deduce it from something else in nature, more known to us than the thing to be explained by it, how can the imploying of incomprehensible (or at least uncomprehended) substantial forms, help us to explain intelligibly this or that particular phenomenon? For to say, that such an effect proceeds not from this or that quality of the agent, but from its substantial form, is to take an easy way to resolve all difficulties in general, without rightly resolving any one in particular; and would make a rare philosophy, if it were not far more easy than satisfactory…” (Origine of Forms and Qualities[1666], in The Worksofthe Honourable Robert Boyle, edited by Birch, Thomas, 6 vols. [London, 1772]; rpt. Hildesheim: Georgolms, 1965; hereafter Works), 3.46–7)Google Scholar.

17 Forster, E. M., Aspects of the Novel (1921; rpt. Harmondsworth: Penguin, 1976), p. 27Google Scholar.

18 Ibid., pp. 30–31. Forster has put his finger squarely on an important point: Sleigh is not relating the Discourse or the Correspondence to “the history of its time,” or to “events in the life of its author.” He is genuinely engaged in the struggle with the writer(s) and their texts; we are being treated to the product of genuine scholarship, not pseudo-scholarship.

19 Grice, H. P., “Reply to Richards,” in Philosophical Grounds of Rationality, edited by Grandy, Richard E. and Warner, Richard (Oxford: Clarendon Press, 1986), pp. 65–66Google Scholar.

20 Snyder, Steven C., “Albert the Great: Creation and the Eternity of the World,” in Philosophy and the God of Abraham: Essays in Memory of James A. Weisheipl, OP, edited by Long, R. James (Toronto: Pontifical Institute of Mediaeval Studies, 1991), p. 192 n.2. Snyder points out that the same feature is to be found in AlbertGoogle Scholar.

21 James Brown has suggested that this is not true of philosophy of physics, which can yield contributions to physics as well as to philosophy. See Brown, James, “Recent Work in the Foundations of Physics,” Canadian Society for the History and Philosophy of Science Communique, 27 (1992): 3–12, esp. p. 7. Some physicists are also, as physicists, competent philosophers, and clearly a similar situation holds with respect to the history and philosophy of mathematicsGoogle Scholar.

22 Let me say explicitly that I do not find this attitude in Sleigh's work.

23 It is often said of various philosophers that their views are intra-systemic. By and large, however, this aspect of the great philosophers of the past is considerably overstated. Dijksterhuis, for example, says of Aristotle: “To Aristotle both [”the so-called vacuum intermixtum or disseminatum” and “the vacuum coac-ervatum”] are equally inconceivable. As we have seen, this opinion is based no t on his establishment either of an internal contradiction in the atomistic doctrine or of the fact that its consequences are contrary to experience, but solely on the incompatibility of the opposed view with his own fundamentally different theories. The only exception is formed by the argument on the impossibility of any absolute determination of place and direction in an infinite homogeneous space. For the rest, the whole argument is emotional rather than logical in character, an expression of self-assertion rather than a refutation” (Dijksterhuis, E. J., The Mechanization of the World Picture [Oxford: Clarendon Press, 1961], p. 40)Google Scholar.

In fact, however, Dijksterhuis has shown us, and we have “seen,” no such thing; in the Physics Aristotle supports his case with good, hard-headed, empirical arguments that depend admittedly on assumptions, but on assumptions that have nothing to do with Aristotle's other metaphysical and scientific views, and everything to do with plausible empirical generalizations and observations (as that, other things being equal, velocity through a medium is proportional to that medium's density, or that things do not travel with infinite speed). That is one reason Bentley still found it necessary to find arguments against them in the late seventeenth century. By contrast, Leibniz's arguments against the vacuum do depend strongly on other elements within his system, as do many of his other claims.

24 There is room for improvement, though. Sleigh's readers would have been helped to move about in the book more easily if one or two editorial matters were arranged differently. In a future edition it would be nice to have the various examples and definitions numbered more enlighteningly, perhaps by number and section, rather than by number alone (“2.1” rather than “1,” “3.4” rather than simply “4,” etc., or better still by chapter, section and number). It would also be appropriate to signal the first, or first important, of the many occurrences of what amount to technical terms (“intrinsic foundations,” etc.) by some typographical device. This is done sometimes (e.g., “The Grounding Principle,” p. 121), but not always. Indeed, there are enough of them so that a brief glossary would not be out of place.

25 A. J. Ayer once remarked in a lecture on the coherence theory of truth, “Part of the heroism of philosophers is that when they do make a mistake they cling t o it, even when as in this case, the consequences are truly outrageous,” and by this definition Leibniz is surely a philosophical hero. There is, of course, also the converse, Lockean, heroism, which consists in abandoning your conclusion as soon as it becomes clear that it is false, and bravely accepting or at least ignoring the resulting inconsistency. Leibniz was aware of this aspect of his thought. He wrote, “It is true that the consequences of a doctrine so evident are paradoxes, but the fault lies with philosophers, who do not take far enough the clearest concepts” (LA, p. 43). Here, as in his much quoted remark about Berkeley, “I suspect that he belongs to the class of men who want to be known by their paradoxes” (Leibniz to Des Bosses, March15, 1715, Gerhardt 2.492, Loemker, p. 609), Leibniz is of course using “paradox” in the standard seventeenth-century sense of “a surprising truth.” The use is similar to our use of “that's incredible” to indicate surprised belief. Leibniz's quarrel was with Berkeley's arguments, or lack thereof, for his conclusions, not with the conclusions themselves.

26 This nominalistic leaning, prompted in part by corpuscularianism, was common in the seventeenth century. Thus Gassendi wrote, “God is the most singular of beings, and all his creatures are particulars: this angel, this man, this Sun, this rock, finally nothing can be met which is not this particular thing” (Pierre Gassendi, Exercitationes, in Opera Omnia, 6 vols. [Lyon, 1658; rpt. Stuttgart-Bad Canstatt: Friedrich Frommann, 1964], 2.93); and Boyle remarks: “whatever men talk in theory of substantial forms, yet that, upon whose account they really distinguish any one body from others, and refer it to this or that species of bodies, is nothing but an aggregate or convention of such accidents, as most men do by a kind of agreement (for the thing is more arbitrary than we are aware of) think necessary or sufficient to make a portion of the universal matter belong to this or that determinate genus or species of natural bodies” (Origine of Forms and Qualities, in Boyle, Works, 3.27). Boyle's earlier remark, however, must be kept in mind: “whenever I shall speak indefinitely of substantial forms, I would always be understood to except the reasonable soul, that is said to inform the human body, which declaration I here desire may be taken notice of once for all” (Origine of Forms and Qualities, in Boyle, Works, 3.12).

27 For a dissenting view see Ayers, Michael, “Individuals Without Sortals,” Canadian Journal of Philosophy, 4 (1974–1975): 113–48.CrossRefGoogle Scholar For an important discussion of the issues involved see chap. 1 of Wiggins, David, Sameness and Substance (Oxford: Basil Blackwell, 1980).Google Scholar

28 Leibniz, Gottfried Wilhelm, New Essays on Human Understanding, translated and edited by Remnant, Peter nd Bennett, Jonathan (Cambridge: Cambridge University Press, 1981), 3.3.6, pp. 289–90. Hereafter New EssaysGoogle Scholar.

29 I am here using the term “properties” generically to cover a variety of seventeenth-century notions including moods, modifications, accidents, qualities, affections, attributes, states and even principles, powers and forms. “Quality” was the preferred umbrella term in English during Leibniz's lifetime. We shall come to some of Sleigh's more precise designations shortly.

30 LA, p. 56. Later Leibniz was to remark to Des Bosses, “I hold, as regards relations, that paternity in David is one thing, and filiation in Solomon another… ” (Leibniz to Des Bosses, April 21, 1714, Gerhardt 2.486.) We should note, however, that in the period under consideration by Sleigh, Leibniz may have been more concerned with showing the possibility of a formal rather than a real reduction of relations. Parkinson points out that earlier in the century Jungius (1587–1657) had discussed the difficulty the logic of the time had with relational arguments of the type of de Morgan's “It is the head of a horse; a horse is an animal; therefore it is the head of an animal,” and suggests that Leibniz's interest may have lain in showing that the logic needed “supplementation rather than expansion.” See Parkinson, G. H. R., transl. and ed., Leibniz: Logical Papers (Oxford: Clarendon Press, 1966), pp. xix–xxGoogle Scholar.

31 As we shall see, for Leibniz in such a universe it would only be the “subordinate maxims” that were indeterministic: the whole structure would be determinedly lawlike.

32 “[T]o say that my successive instantaneous states are not one state but several is one thing, while to say that I in those states am not one but several individuals is to say quite another thing, and a thundering silly thing at that” (Arthur Prior, “Report on Analysis 'Problem' No. 11,” Analysis, 17, 6 [1957]: 123); but why is it silly for Leibniz?

33 LA, p. 43.

34 This is not t o disagree with Sleigh's assuredly correct general point that “Leib-niz, although a genius at devising logical systems and locating subtle logical errors in the arguments of his fellow philosophers, was not given to clear formulations of arguments for his own metaphysical conclusions” (p. 89).

35 I do not suggest that these are all of Thomas's versions of necessity. The list is not meant to be, and is not, exhaustive. For a helpful and interesting discussion of both Thomas and Ockham on modality see Wolter, A., “Ockham and the Textbooks: On the Origin of Possibility,” Franziskanische Studien Vierteljahr-Schrift, 32 (1950): 70–96, rpt. inGoogle ScholarInquiries into Medieval Philosophy, edited by Ross, J. (Westport, CT: Greenwood Publishing, 1971), pp. 243–73Google Scholar. In “St. Thomas'Doctrine of Necessary Being” (The Philosophical Review, 73 [1964]: 76–90), Patterson Brown clears up a number of confusions surrounding St. Thomas's views on necessary existence. A useful general survey of the medieval background may be found inCrossRefGoogle ScholarKnuuttila, Simo, “Modal Logic,” in The Cambridge History of Later Medieval Philosophy, edited by Kretzmann, Norman, Kenny, Antony and Pinborg, Jan (Cambridge: Cambridge University Press, 1982)Google Scholar.

36 There was a certain amount of debate about this, but not much, and certainly St. Thomas accepted Agathon's point (Summa Theologiae [hereafter ST] 1.25.4 ad 1). Quotations from the Summa are from the Blackfriars edition, 61 vols. (Blackfriars, in conjunction with Eyre & Spottiswoode, London, and McGraw-Hill, New York, 1964–81), various translators and editors.

37 Even in the “state of innocence, man did not know future contingent events except in their causes or in the Word, just as the angels know them” (De Veritate, 8.12 ad 9).

38 It is clear that this present sort of necessity, necessityper accidens, leads to a further necessity: that which we have when something is now necessary per accidens, always has been, and always will be. Calvin Normore points out that these various necessities can be defined in terms of a primitive notion of determinate truth. See Normore, Calvin, “The Logic of Time and Modality in the Later Middle Ages: The Contribution of William of Ockham,” unpublished Ph.D. thesis, University of Toronto, 1975, National Library of Canada No. TC35093, p. 261Google Scholar.

39 “Since St. Peter will deny our Lord” was Leibniz's original example.

40 “In order that it may be in the subject” (DM§13).

41 ST 1^a 46.2 resp. For Philoponus see the report by Simplicius, in Physica 1178, 6–1179, 26, in Philoponus, John, Against Aristotle on the Eternity of the World, translated by Wildberg, Christian (London: Duckworth, 1987); for Bonaven-ture's almost identical arguments see St. Bonaventure, In II Sent., d.1, p.1, a.1, q.2, translated byGoogle ScholarByrne, P. M., in Bonaventure, St., Selected Texts on the Eternity of the World, in St. Thomas Aquinas, Siger of Brabant, St. Bonaventure, On the Eternity of the World (Milwaukee: Marquette University Press, 1964); forGoogle ScholarSteenberghen, Van see Thomas Aquinas and Radical Aristotelianism (Washington: Catholic University of America Press, 1980), pp. 25–26. A number of conservative philosophers such as John Pecham and Henry of Ghent offer similar arguments. About the actual universe Aquinas agrees with Leibniz: time and the universe are co-created, though this is not a conceptual necessity for Aquinas as it is for LeibnizGoogle Scholar.

42 ST 1^a14.13ad3.

43 ST 1^a 23.3 ad 3. Absolute necessity is discussed at length in Summa Contra Gentiles 2.30.

44 ST 1.23.3 ad 3.

45 Remember that for Aquinas the conditional was closer to our strict implication than to the material conditional.

46 De Veritate, 2.12 obj 7. Calvin Normore points out that a more sophisticated version of the same argument is found in Peter Aureoli, who uses it to argue explicitly for a truth gap theory: “Hence this is not true ‘The Antichrist will be’ nor also this ‘The Antichrist will not be’ but well indeed is the disjunction ‘The Antichrist will be or he will not be’” (Peter Aureoli, Commentarium in primum librum Sententiarum, D.38, art. 3, quoted in Normore, , “The Logic of Time and Modality in the Later Middle Ages,” p. 230). The same point is made byGoogle ScholarNormore, in “Future Contingents,” in , Kretzmann et al, eds., The Cambridge History of Later Medieval Philosophy, pp. 369–70, where he also points out, followingGoogle ScholarBaudry, Leon (La Querelle des futurs contingents [Louvain 1465–1475], [Paris: J. Vrin, 1950]), that it is Aureoli whose view Peter de Rivo is defendingGoogle Scholar.

47 Aquinas returned to the issue, without any greater success, in the slightly later Summa Contra Gentiles, Bk. 3, chap. 94. See further Prior's, Arthur discussion in “The Formalities of Omniscience,” Philosophy, 37 (1962), reprinted in A. N. Prior, Papers on Time and Tense (Oxford: Clarendon Press, 1968), pp. 31–35CrossRefGoogle Scholar.

48 William, of Ockham, , Tractatus de Praedestinatione et de Praescientia Dei Respectu Futurorum Contingentium, edited by Philotheus Boehner, in Opera Philosophica II (New York: St. Bonaventure, 1978), Q2, art 4, 2.530, translated byGoogle ScholarAdams, Marilyn McCord and Kretzmann, Norman as Predestination, God's Foreknowledge, and Future Contingents (Indianapolis: Hackett, replacing Appleton-Century-Crofts, New York, 1969), p. 67, translators' emphasis. Adams and Kretzmann point out that the expected construction is “God knows contingently that it will be,” which seems to be Ockham's clear intention, but they note that their translation is required by the Latin. In the Ordinatio, where Ockham is making the same point, he remarks that “God contingently knows that it will be” (Scriptum in Librum Primwn Sententiarum [Ordinatio], Distinctiones XIX- XLVIII, edited byGoogle ScholarEtzkornet, G. I. and Kelley, F. E., Opera Theologica IV [New York: St. Bonaventure, 1979], L 1, dist 38, 4.587; p. 91 in Adams and Kretzmann, Predestination, where distinctions 38 and 39 are translated as Appendix I)Google Scholar.

49 Normore, Calvin in “Future Contingents” remarks: “This seems plausible where X [the knower] is a fallible creature but less plausible where X is God” (p. 372)Google Scholar.

50 “[Q]uod possible est non esse, quandoque non est” (ST l^a 2.3 resp).

51 ST 1^a 14.9 resp. Ockham agreed with Thomas on this point. For an illuminating discussion see , Normore, “The Logic of Time and Modality in the Later Middle Ages,” p. 225Google Scholar.

52 See further De Potentia, 5.5.3.

53 DM§14.

54 LA, p. 98.

55 Aquinas, Thomas, In Perihermeneias, I, L14, 20–21, translated byGoogle ScholarMartin, Christopher in The Philosophy of Thomas Aquinas (London: Routledge, 1988). Cf. De Veritate, 2.12.7 ad, where much the same points are made. Compare alsoGoogle ScholarScotus, Duns: “by 'contingent ' I do not mean something that is not necessary or which was not always in existence, but something whose opposite could have occurred at the time that this actually did. That is why I do not say that something is contingent, but that something is caused contingently” (Wolter, A., ed. and transl., Duns Scotus Philosophical Writings, [Indianapolis: Hackett, 1987], p. 55)Google Scholar.

56 “[U]t contingentia futura, quorum veritas non est determinata” (ST 2^a 2^æ 171.3 resp).

57 Locke to William Molyneux, January 20, 1693, The Correspondence of John Locke, edited by Beer, E. S. de (Oxford: Clarendon Press, 1979), 4.625–26Google Scholar.

58 Boyle Papers 2.49–50. Words appearing here within brackets (f,]) are Boyle's deletions, within angle braces (<,>), his insertions. I am grateful to the Royal Society for permission to quote from the Boyle papers.

59 DM§13.

60 Adams, Robert M., “Predication, Truth and Transworld Identity in Leibniz,” in How Things Are, edited by Bogen, James and McGuire, James E. (Dordrecht: D. Reidel, 1985), pp. 235–83, p. 238CrossRefGoogle Scholar.

61 It is interesting that this definition, so prominent in Leibniz, has not survived, while the account in terms of possible worlds, used by Leibniz mainly in theological discussions of free will, now occupies the centre of the modal stage.

62 Adams, , “Predication, Truth and Transworld Identity in Leibniz,” p. 237Google Scholar.

63 DM §2.

64 LA, p. 44, Sleigh's translation.

65 The Adams quotation is from Adams, Robert M., “Primitive Thisness and Primitive Identity,” Journal of Philosophy, 76 (1979): 5–26, p. 7. Sleigh adds the following caution in a footnote: “the weak thesis of intrinsic foundations is a strong thesis. It is here termed weak in relation to a still stronger version that is forthcoming.”CrossRefGoogle Scholar

66 Also: “x has f perpetually just in case x has f at every time at which it exists. Leibniz seems committed to the thesis that any property an individual has essentially, it also has perpetually” (p. 203 n.27).

67 Sleigh directs our attention to the fact that “… 'intrinsic' is used in connection with two entirely different ideas The notion of having a property intrinsically is a different notion from that of a property being intrinsic, or being an intrinsic denomination” (p. 206 n.64).

68 Sleigh offers LA, pp. 42 and 53, and DM §30, as evidence for Leibniz's acceptance of superintrinsicalness (p. 203 n.28).

69 Throughout I have followed Sleigh and used a sentential operator “ □ ” for “metaphysical” necessity. I suspect, though, that the required metaphysical necessity operates on predicates and thus, unlike ordinary necessity, will not have a dual unless we allow predicate negation.

70 Brown, Stuart, Introduction, in G. W. Leibniz: Discourse on Metaphysics and Related Writings, edited and translated by Martin, R. N. D. and Brown, Stuart (Manchester: Manchester University Press, 1988), pp. 28, 29Google Scholar.

71 DM §34.

72 Ch. , Adam and Tannery, P., eds., Oeuvres de Descartes (Paris: J. Vrin, 1964–1976), 4.576Google Scholar.

73 Locke, John, Essay Concerning Human Understanding, edited by Nidditch, P. H. (Oxford: Clarendon Press, 1975), 2.8.13. The same point may be found at a number of places in Boyle, e.g., “the very conditions of the union of the soul and body; which being settled at first by God's arbitrary institution, and having nothing in all nature parallel to them, the manner and terms of that strange union is a riddle to philosophers, but must needs be clearly known to him, that alone did institute it, and, (all the while it lasts) does preserve it” (Google ScholarBoyle, R., Of the High Veneration Man's Intellect Owes to God, Peculiarly for His Wisdom and Power [1685], §32, in Boyle, Works, 5.150). More explicitly with regard to sensation in particular he wrote: “The Phenomena of Sensation; not as they are changes in the Objects, but in the Organs (External or Internal) of the Sentient; are arbitrary: there being no cause why Blew and Yellow for instance should make a Green and not a Pinke nor a Purple Colour; but the Law's wch. God freely establish'd of the Union between the Humane Soul and Body” (Boyle Papers 9.40r.)Google Scholar.

74 Leibniz, , New Essays, p. 131. There was, at the time, a standard counter-example to the resemblance thesis, urged by Galileo (in Il Saggiatore) early in the century. Here it is in Boyle's wording: “To shew how little resemblance there may be between the Effect of a quality as 'tis produc' d in the sentient, and that wch i s fancy'd to be inherent in the Body that acts to produce that Effect; we may consider how little resemblance there is between the forced Laughter that is caus'd by Tickling and the end of a Straw or Feather, wch by its languid motion produces that Laughter” (Boyle Papers 9.99)Google Scholar.

75 Daspodius, Konrad, Brevis doctrina de cometis, et cometarus effectibus (Strasbourg, 1578), CIII (3), quoted inGoogle ScholarRuby, Jane E., “The Origins of Scientific 'Law',” Journal of the History of Ideas, 47: 341–59, 356CrossRefGoogle Scholar.

76 Z)M§6.

77 Boyle, R., Origine of Forms and Qualities, in Works 3.48, and cf.Google ScholarBoyle, R., Of the Usefulness of Natural Philosophy, in Works 2.48Google Scholar. Hooke argues for the same ordering in “Of Comets & Gravity,” Posthumous Works, edited by Waller, Richard (London, 1705), pp. 174–75. Leibniz agrees as far as mechanical laws go: “I am of the opinion of Mr Cudworth… that the laws of mechanism alone could not form an animal, where there is as yet nothing organized” (Gerhardt 6.543; Loemker, p. 589)Google Scholar.

78 “[H]owever much I agree with the Scholastics in this general and, so to speak, metaphysical explanation of the principles of bodies, I am as corpuscular as one can be in the explanation of particular phenomena, and it is saying nothing to allege that they have forms or qualities” (LA, p. 58). A version of this position may be found earlier. In 1677 Leibniz wrote: “I take it to be certain that all things come about through certain intelligible causes, or causes which we could perceive if some angel wished to reveal them to us. And since we may perceive nothing accurately except magnitude, figure, motion, and perception itself, it follows that everything is to be explained through these four” (Leibniz, “On a Method of Arriving at a True Analysis of Bodies and the Causes of Natural Things”; Gerhardt 7.265; Loemker, p. 173). Later, writing to Huygens about Boyle, Leibniz remarks that “we all know [that] everything happens mechanically” (in Oeuvres Completes de Christiaan Huygens, 23 vols. [The Hague: Martinus Nijhoff, 1888–1950], 10.228, 12 29,1691)Google Scholar.

79 “Even if one were to discount the hermetic and allegorical aspects of alchemy, the store of accumulated knowledge of chemical change might suffice to convince any but the most reductionist Cartesian or atomist that some further principles of explanation would be needed than bare matter and motion. Newton, at least, was quite convinced” (in McMullen, Ernan, Newton on Matter and Activity[ Notre Dame: University of Notre Dame Press, 1978], pp. 44–45)Google Scholar.

80 LA, p. 43.

81 Thus the set of laws is different for every possible world. Of course it does not follow that the laws of nature, the subordinate maxims, must be different. Sleigh points out that the textual support for every world having different laws is equivocal, but I think it is a view that Leibniz is committed to (pp. 73, 205 n.57.)

82 LA, p. 42. Talk of “our Adam” often strikes contemporary readers as reminiscent of David Lewis's counterpart theory. For arguments against such a reading, see Wilson, Margaret, “Possible Gods,” Review of Metaphysics, 32 (1979): 717–33, and Adams, “Predication, Truth and Transworld Identity in Leibniz.”Google Scholar

83 Adams, , “Predication, Truth and Transworld Identity in Leibniz,” p. 237Google Scholar.

84 For appropriate, i.e., transparent, (ø's, many would say—but it is not clear to me whether Leibniz would be among them.

85 It was axiomatic at the time that there was a single underlying matter. Thus Boyle writes, “I agree with the generality of philosophers… that there is one catholick or universal matter common to all bodies, by which I mean a substance extended, divisible, and impenetrable” (Origine of Forms and Qualities, in Boyle, Works 3.15).

86 “All these things being consider'd, it seems probable to me that God in the Beginning form'd Matter in solid, massy, hard, impenetrable, moveable Particles, of such Sizes and Figures, and with such other Properties, and in such Proportion to space, as most conduced to the End for which he form'd them…” (Issac Newton, Optics, 4th ed. [London, 1730Google Scholar; rpt. New York: Dover, 1952], Qu 31). Later, Leibniz was to suggest an additional reason for rejecting such atoms: “I maintain that in the natural course of things no substance can lack activity, and indeed that there is never a body without movement. Experience is already on my side, and to be convinced one need only consult the distinguished Mr Boyle's book attacking absolute rest” (Leibniz, , New Essays, Preface, p. 53)Google Scholar. Leibniz is here, inter alia, attacking atoms, since they would be internally at rest. In their note to this passage, Remnant and Bennett point out that the reference is to Certain Physiological Essays, which appeared in English and Latin in 1661. It eventually went through two English and nine Latin editions, and included an essay “Of absolute Rest in Bodies. An Essay of the intestine Motions of the Particles of quiescent Solids, where the absolute Rest of Bodies is called in question.”

87 See, e.g., Monadology §9.

88 Leibniz makes the point that the Identity of Indiscernibles is parasitic on the principle of Sufficient Reason in a number of places. We find it, for example, in “First Truths,” written in the early 1680s, and it can be found still in the correspondence with Clarke, ended by Leibniz's death in 1716. In the fifth letter to Clarke (in The Works of Samuel Clarke, D.D.,4 vols. [London, 1738, rpt. New York: Garland Publishing, 1978], Vol. 4, §§21 and 25, Leibniz noted that nonidentical indiscernibles are logically possible, but claimed that their existence in the actual world is blocked by the principle of sufficient reason (“c'est une chose contraire a la Sagesse Divine, & qui par consequent n'existe point”)Google Scholar.

89 See further “Primitive Thisness and Primitive Identity,” p. 24, where Adams argues “that there are possible cases in which no purely qualitative conditions would be both necessary and sufficient for possessing a given thisness.”

90 Referring to “ce grand Principe du besoin d'une Raison suffisante pour tout evenement” Leibniz says, 'Ten infere… qu'il n'y a point dans la Nature deux Etres reels absolus indiscernables; parceque s'il y en avoit, Dieu & la Nature agiroient sans Raison, en traitant l'un autrement qu l'autre; & qu'ainsi Dieu ne produit point deux portions de matiere parfaitement égales & semblables” (Leibniz's fifth letter to Clarke, §§20–21,4.636–37).

91 There are really two points here. With respect to the actual world, St. Thomas argued, finite intelligences, including even the angels, are restricted (unlike God), when what is at issue is knowledge of singulars, to past and present individuals: “I grant that an angel's ideas [species qua sunt in intellectu angeli], precisely as ideas, are equally related to the present, the past and the future; nevertheless the present, the past and the future are not equally related to those ideas. Things existing in the present have a nature by which they resemble the ideas in an angel's mind, so that through these ideas they can be known by him. But what is yet to be has not yet got a nature through which to resemble those ideas; hence it cannot be known through them” (ST la 57.3 ad 3).

The point at issue is discussed by Prior, Arthur in “Identifiable Individuals,” in Review of Metaphysics, 13 (1960): 521–39Google Scholar; rpt. in Prior, Arthur, Papers on Time and Tense (Oxford: Clarendon Press, 1968), chap. 7, pp. 66–77Google Scholar. See also De Potentia 3.1–3 and ST 1^a 57.2.

With respect to merely possible individuals, God, who knows even future singulars “in themselves,” has knowledge of possibilia in a different manner: ”[W]e have to take account of a difference among things not actually existent. Some of them, although they are not now actually existent, either once were so or will be: all these God is said to know by knowledge of vision. The reason is that God's act of knowledge, which is his existence, is measured by eternity which, itself without succession, takes in the whole of time and therefore God's present gaze is directed to the whole of time, and to all that exists in any time, as to what is present before him. Other things there are which can be produced by God or by creatures, yet are not, were not, and never will be. With respect to these God is said to have not knowledge of vision, but knowledge of simple understanding. The reason for the names is that in ourselves things seen have a separate existence outside the one who sees (ST la 14.9 resp.).

92 Prior, , “Identifiable Individuals,” p. 77Google Scholar.

93 Leibniz, Fourth letter to Clarke, §§5–7.

94 New Essays, p. 110. For Leibniz on infinite possible worlds see LA, pp. 40, 51; for Arnauld, LA, p. 64.

95 St. Thomas's point was, in part, that the angels (who “exist in exceeding great number, far beyond all material multitude”), being incorporeal, must be separate in their species, since otherwise there would be no principle of individuation. For humans, as for other animals, our being material provides an individuating principle (ST 1^a 50.3 resp., ST 1 ^a 50.4 resp.). Newton went so far along this road as to speculate that in humans the soul is simply the vivifying factor, while both individual and species differences result from “the different tempers and modes” of the bodies in question. Newton offered by way of (somewhat obscure) textual support a reference to Ecclesiasticus 33.10: “All men alike come from the ground; Adam was created out of earth” (Certain Philosophical Questions, edited by McGuire, J. E. and Tamny, M. [Cambridge: Cambridge University Press, 1983], p. 83/129r; M&T, p. 449)Google Scholar.

96 DM§§-9. Passages enclosed in angle brackets are Leibniz's insertions; in double angle brackets, his insertions within insertions.

97 I have benefited while writing this paper from conversations with my colleague Ali Kazmi.