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Wonder in the face of scientific revolutions: Adam Smith on Newton's ‘Proof’ of Copernicanism

2005; Taylor & Francis; Volume: 13; Issue: 4 Linguagem: Inglês

10.1080/09608780500293042

1469-3526

Eric Schliesser,

Classical Philosophy and Thought

Click to increase image sizeClick to decrease image size Notes 1I am indebted to Dan Garber, Charles Larmore, Sam Fleischacker, David Levy, Spencer Pack, Warren Samuels, Howard Stein, Alessandro Pajewski, Joe La Porte, Andrew Skinner, Jen Boobar, Andrea Woody, and an anonymous referee of this journal as well as audiences at the University of Washington, Seattle, and the University of Chicago for many thoughtful comments. Elias Khalil was kind enough to share with me his forthcoming piece. I owe a special debt of gratitude to Red Watson and Abe Stone for their many detailed comments and, especially, Leonidas Montes and Christopher Berry, who reached similar conclusions with very different arguments, and who have been generous in their comments on this paper. 2See, for example, S. Cremaschi Citation1989; C. L. Griswold, Jr. 1999, especially, chs 4, 8 and the Epilogue; Pack Citation1991, p. 114, and E. Rothschild Citation2001, pp. 138 – 140 and p. 229. 3Some terminological clarification: in the paper: I use 'skepticism' to mean Hume's 'mitigated skepticism', that is, one that results in the 'limitation of our enquiries to such subjects as are best adapted to the narrow capacity of human understanding' (Hume Citation1999, XII.III.25, 208). The affirmation of this 'mitigated skepticism' is said to be a 'natural result of the Pyrrhonian doubts and scruples', and is, hence, not an alternative to it. For Hume the appearance of Pyrrhonian doubts always remain a live possibility that cannot be argued against. At the same time, for Hume one cannot live according to Pyrrhonian scruples. Pyrrhonian doubt is a philosophic doctrine, while mitigated skepticism is, perhaps, the result of philosophizing, an attitude we can adopt in our daily lives that will allow us 'never [to] be tempted to go beyond common life'. It, thus, presupposes a distinction between common life and abstract philosophy. See, also, De Pierris 2001 and 2002. In the body of the text, I argue that Smith rejects this view because it is entirely reasonable to accept scientific theories that are deeply at odds with common life. Smith is also committed to the view that scientific theories can transform common sense. Nothing I say bears directly on Smith's attitude toward Pyrrhonian skepticism as a philosophic doctrine. My use of 'realism', which I sometimes oppose to 'relativism', is less easily defined because I argue that, for Smith, the norms that are taken to be constitutive of realism can change over time in an open-ended fashion. 4Smith's interest in the sciences is not merely theoretical. I discuss the political role of science in Smith in Schliesser (forthcoming). I discuss Smith's interest in history in Schliesser 2005b. 5I discuss this in my Schliesser 2005c. 6Following A. S. Skinner, I understand Smith as extending and refining the various elements of Hume's 'Science of Man'. Smith acknowledged the intellectual affinity between his work and that of Hume in Letter No. 261 to Thomas Cadell, his publisher, of 7 May 1786; Correspondence, p. 296. Smith's treatment is also reminiscent of Turgot's 'A Philosophical Review of the Successive Advances of the Human Mind', first presented to the Sorbonne on 11 December 1750 (see the translation in Ronald L. Meek 1973). Yet, Smith's account is far more detailed about and ambitious in its description of the contents of the various theories adopted. Of course, it is nowhere near as detailed and exhaustive as the great history of mathematics, including astronomy, Montucla Citation1758. 8For more details on Smith's approach to wonder, admiration and surprise, see Lindgren Citation1969, pp. 897 – 907, or my 'Science and Miracles' (under review). 7The rhetorical structure of 'Astronomy' seems designed, first, through its unexpected start, to surprise and, second, through its novel approach to induce wonder (Cf. TMS I(i):4.3, 20, and I(ii):1.12, 31). 9For more on Smith's views on these sentiments, see his Lectures on Rhetoric and Belles Lettres. (LRBL), Lecture (i): 164 – 5, 68 – 9. In Part 1 of TMS admiration is defined as 'For approbation heightened by wonder and surprise, constitutes the sentiment which is properly called admiration, and of which applause is the natural expression' (TMS I(4):3, 20). The editors of TMS claim that this definition contradicts the account offered in the 'Astronomy' because it suggests that these sentiments are not distinct. They ignore, however, that in the 'Astronomy' Smith calls these sentiments 'allied' and only 'in some respects different … and distinct from one another'. 10For more details, see Schliesser 2005a, where Smith's methodological views are analysed. 11Smith may have believed that observing similarity is an innate capacity because at several points in 'Of the External Senses', Smith suggests that various capacities may be instinctive: (a) fellow feeling with other men and to a lesser degree animals (¶7, 136); (b) perception of the connection between visible and tangible object (see ¶69ff., 161, with an appeal to Linnaeus' and his own observations); and (c) the appetite of sex (¶79, 165). For a list that includes 'Hunger, thirst, the passion which unites the two sexes, love of pleasure, and the dread of pain', see the long footnote appended to TMS II(i):5.6, 78. In the context of a passage on the effects of music in 'Of the Nature of the Imitation which takes place in what are called the Imitative Arts' (hereafter 'Imitative Arts'), Smith provides a general account of the mind's receptivity (when despondent) towards resemblance (see II¶20, 197). Although Smith never explicitly mentions natural philosophy in the passage, he does compare the 'very high intellectual pleasure' derived from contemplating systems of music with systems of other sciences shortly hereafter in the same essay ('Imitative Arts', II¶30, 205). The 'Imitative Arts' first appeared after Smith's death in EPS. Correspondence, Letter No. 208, 252, from 1780, suggests that he had been working on the essay in the late 1770s. There is also some reason to believe that parts of the work had been presented to the Glasgow society in the late 1750s or early 1760s. See the Editors' Introduction, EPS, pp. 172 – 3. 12See Skinner Citation1979, p. 38. For more skeptical comments on the use of analogy, see Smith's students' lecture-notes of LRBL, lecture 6(i):62, 28 and Lecture(i):164 – 5, 68 – 69. In the 'Astronomy', Smith claims that Kepler had an excessive 'passion for discovering proportions and resemblances betwixt the different parts of nature', (IV¶50, 84). 13Haakonssen Citation1981, 79 – 82, claims that in Smith there is an (implicit) distinction between contextual knowledge and system knowledge, the former being 'the knowledge we have of human behavior through the sympathy mechanism', while the latter is 'the understanding of things, events, or persons in some sort of functional relationship to a greater 'whole' or system'. Although not implausible, Haakonssen offers little textual evidence. For a partial defence of Haakonssen, see Fiori Citation2001: 435, and Fleischacker Citation2004. Smith did clearly think that there were different kinds of interest in, requirements on, and expectations from knowledge in moral and natural philosophy (TMS VII(ii):4.14, 313 – 4). For more on Smith's account of philosophy, see Schliesser forthcoming. 14In Letter No. 208, 1780, Smith writes that he spent six years in the place of his nativity: 'During this time I amused myself principally with writing my Enquiry concerning the Wealth of Nations, in studying Botany (in which however I made no great progress) as well as some other sciences to which I had never given much attention before' (Correspondence 252). Smith's interest in Botany is also attested by his knowledgeable remarks on works by Buffon and others in his first publication, the 'Letter to Edinburgh Review', ¶8 – 9, 248 – 9, EPS. 15In the debate on nature vs. nurture Smith is clearly on the side of nurture. (Hume thought nurture merely 'widened' already wide differences in natural endowments. See Second Enquiry 1.1.2.) But Smith's terminology is confusing because he thinks that socialization is natural; see TMS VI(ii):1.10 – 7, 222 – 4. On education, see also WN V(i):f – g, 758 – 814. For more on the difference between artisan and natural philosopher in Smith, see Fiori Citation2001, pp. 435ff. 16Turgot uses similar language in his (1750) 'A Philosophical Review of the Successive Advances of the Human Mind', in Meek 1973: 45. Turgot is more impressed than Smith by the contribution artisans have made to knowledge throughout history (pp. 55 – 8). 17Skinner Citation1979: 20 – 1. I offer a more elaborate discussion in my 'Science and Miracles'. 18Hume's essay, 'The Rise and Progress of the Arts and Sciences', is more thorough about all of this. Cf. Turgot's 'A Philosophical Review of the Successive Advances of the Human Mind', in Meek 1973: 42ff. 19For more on this issue, see Schliesser (forthcoming). In 'Astronomy', Smith alludes to none of Galileo's troubles with the Church. 20For Smith, explanation often seems to consist in the proving of the existence of a connecting chain from some unusual event, e.g. an eclipse, 'to the ordinary course of things' ('Astronomy', II¶9, 43). Of course, theories that manage to knot together unusual events with ordinary course of things may be counterintuitive ('Astronomy', IV¶33, 75). 21There are, of course, political echoes, e.g. the 'Glorious Revolution' of 1688; cf. TMS VII(iv): 37, 342. 22In fact, there are several examples of this in d'Alembert's Preliminary Discourse. For more on all of this, see Cohen Citation1985, although there is no mention of Adam Smith. Cohen comments favorably on 'Astronomy' in Cohen Citation1994: 62, and before he died he was kind enough to share some notes on Adam Smith with me. 23See An Apology for Raymond Sebond, pp. 149 – 150. 24OED cites Johnson's Rambler (1751) as follows: 'The changes which the mind of man has suffered from the various revolutions of knowledge.' Maclaurin Citation1748, p. 39, may contain an earlier usage: 'It is not worth while, nor of use for our purpose, to trace the history of learning thro' its various revolutions in the later ages, when philosophy and philosophers fell into contempt.' Hume's letter to Henry Home, 13 February 1739, may be the earliest instance of all (see also Hume's 'Of the Standard of Taste', EMPL, 242). 25One reader suggested that Smith's use of 'revolutions' in the passage (II¶12) could be in terms of (astronomical) revolutions of planets where the orbits go full cycle and return to their original position. After all, Smith uses the word 'revolution' in precisely this latter sense in the 'Astronomy' at IV¶13, 62. This seems to be the use that Turgot employs in the first section of his 'A Philosophical Review of the Successive Advances of the Human Mind', first presented to the Sorbonne on 11 December 1750 (in Meek 1973); but it is not the point of 'Astronomy' II¶12, 46 to claim that after some changes the theories return to the same place. Instead, Smith is describing how theories get abandoned for new ones, so Smith uses 'revolutions' in two different ways in the same work. 26See Skinner Citation1979: 26 – 9, for more details. In his account of the transition from Descartes to Newton, Turgot describes something like this in his (posthumously published in 1808 – 11) 'On Universal History', in Meek 1973: 95. Unlike Smith, Turgot calls attention to the importance of Richer's findings. 29For a more thorough investigation of the role aesthetic criteria play in Smith's theory of inquiry, see, besides Khalil (forthcoming), Lindgren Citation1969, especially pp. 902 – 7, where comprehensiveness, coherence, familiarity and beauty are suggested as necessary and sufficient conditions for the successful completion of inquiry. Lindgren's approach is notable because it draws also upon Smith's essay, 'Of the Nature of that Imitation which takes place in what are called the Imitative Arts'. (See also Smith's comments at WN V(i):f.25, 768 – 769.) See also Griswold 1999: 311 – 54. Griswold notes, too, with reference to the ethical discussion in TMS VII(ii):2.14, that Smith realized that too much attention to the beauty of a system and too little to the phenomena can have distorting effects (p. 335). 27See Lindgren Citation1973: 18, and Skinner Citation1979: 35. Skinner Citation1979: 40 – 4, makes some useful comparisons to Shackle 1957 and Popper Citation1959. Polanyi Citation1958, with its emphasis on the importance of the 'intellectual passions' should be added to this list. 28See Khalil (forthcoming). 30See also Berry's piece to appear in Cambridge Companion to Adam Smith. 31Quine Citation1969: 88. 33A former student, Margaret Smith, has argued in an unpublished essay that Swift could have derived his view from Bacon's description of one of 'the idols of the mind' in New Organon; see especially section 44 on the 'idols of the theatre' or the 'various dogmas of philosophies' and sections 38 – 46. 32In LRBL, Smith mentions Swift quite frequently and often with high praise ('remarkable for his propriety and precision', Lecture 8(i):100, 41; Lecture 9(i):125, 51). In Lecture 10(i):127, 52, there is an allusion to the passage I cite: '([Lucian] would not … put a Ludicrous speech into the mouths of a dead man or a god) or from throwing out such biting sarcasms in his own person as Swift often does [sic].' Smith owned Swift's Works (see Yanaihara Citation1966: 91). Swift may have been Smith's source that admiration, surprise and wonder are the crucial 'intellectual' sentiments (see Gulliver's Travels, Book IV.I). 34Forbes Citation1975: 186, ascribes various forms of relativism to Smith, but without evidence with respect to Smith's philosophy of science. 35See Wightman Citation1975: 60. 38Smith's description of what 'the great difficulty seems to be' is puzzling. Newton's theory is not committed to positing 'the smallest particle of matter that is perfectly at rest, with regard to all other surrounding bodies'. In De Gravitatione (unavailable to Smith), Newton denies this explicitly (see Newton Citation2004). Perhaps, Smith was, as the editors of EPS note, echoing Berkeley's treatment of Newton's views on absolute space. It is true that, if Newton is correct, one could say of one body, in an otherwise empty universe, whether it is rotating or not (Di Salle Citation2002: 43). 36See also Wightman Citation1975: 61. 37The presence of simplicity contradicts Lindgren's claim that Smith's attack on 'men of system' rested exclusively on their 'propensity to account for all appearances from as few principles as possible' (see Lindgren Citation1973: 4, n.4). Lindgren appeals to TMS VII(ii)4.14, 313 – 14. In these passages, Smith attacks misguided abstraction in social science not simplicity. Smith thinks that explanations in natural philosophy may be strange and counterintuitive but not in moral philosophy, where they must appeal to familiar principles in order not to 'appear absurd to the most injudicious and unexperienced reader'. It is a little puzzling that Lindgren Citation1973: 16, is blind to this because he is aware that Smith takes Hume to task (at TMS IV 179 – 93; see also Smith's warnings against the 'man of system' at VI(ii):2.17 – 18, 233 – 4) for relying on a notion of utility that abstracts away from people's actual preferences. For more on this, see Schliesser and Pack. For similar warnings against abstraction in moral philosophy, see also TMS II(iii):i.intro.5, 93. (Cf. Hume's 'Of Parties in General', EMPL, 54 – 63.) See Brubaker Citation2002, but Brubaker errs in representing Smith as an enemy of abstract study of human nature. See, e.g., TMS III//(3):2 – 3, 134 – 5, and VII(iii): 2.4, 319, which imply, while criticizing Hobbes, that (recent) advances in the abstract science of human nature have enabled a more accurate understanding of the relationship between virtue and the faculties of the mind. See also, Haakonssen Citation1981: 149. 39For a similar conclusion, but with a different argument, see Skinner Citation1996, 41. The epistemological importance of the social nature of science is an important theme. (Recall 'Astronomy', II¶12, 46.) For Smith, science is a social enterprise in which the participants use reasons to gain each other's, and their own, approval. Hume also thinks of 'the approbation of the public … as the greatest reward of [his] labours; but [Hume is] determin'd to regard its judgment, whatever it be, as [his] best instruction'. ('Advertisement' to the Treatise.) 40This breaks with Hume's epistemology, which defends common life (see Livingston Citation1984). 41See also Smith's comments on Reamur's History of Insects in his 'Letter to Edinburgh Review', ¶9, 249, EPS. 42Fleischacker 1999 emphasizes the importance of judgement in Smith's philosophy. 43This passage is ignored by those, e.g., Cropsey Citation1957: 7 – 9, and Griswold 1999, that claim that Smith believed that philosophy is not an end in itself. Such a position seems to be suggested by TMS I(i):4.5, 21. I discuss these views in Schliesser forthcoming. 44 Discourse on the Sciences and Arts, Part II, ¶39, OC III, 18. 45For more on this, see Griswold 1999, ch. 2; Otteson 2002, chs 2 – 3; Darwall Citation1998 especially pp. 264 – 9, and Levy & Peart Citation2004. 46Raphael Citation1975: 92ff. 47D'Alembert [1963] Citation1995: 93, also had no doubt about this. For more on love and friendship as reward for virtue, see Cropsey Citation1957: 51 – 2; Den Uyl and Griswold 1966; Schliesser Citation2003. 48See Gerschlager Citation2002 and Schliesser forthcoming. 49My appropriation to epistemology of Smith's notion of the 'Impartial Spectator' is not unwarranted. Although TMS is devoted to moral and not 'intellectual sentiments' (Cropsey Citation1957: 43, n. 3 introduces this phrase), Smith comments frequently on the nature of natural philosophy in TMS (IV(2):7, 189; III(2): 20 – 22, 124 – 5; I(i): 4.3 – 5, 20 – 1). He also assigns it a crucial role in correcting our standpoint (TMS III(3):2 – 3, 134 – 5; see also Smith's 'Of the External Senses', ¶43ff, 54 – 6). At TMS I(i):4.3, 20, and VI(i):15, 216, Smith talks about the 'intellectual virtues' of the 'experienced mathematician' and 'the great leader in science and taste'. Griswold 1999: 78, points out that the opening lines of TMS indicate Smith's concern with epistemology in that book; see also, Griswold 1999, ch. 4, for more on 'intellectual sentiments'. 50Cf. TMS I(i):4.10, 23, and II(ii):2.3, 84 – 5. Given the biographical evidence available to Smith (i.e. Fontenelle's Life of Newton, 1728, a copy of which Smith owned in French (Fontenelle Citation1790), see Yanaihara Citation1966: 115), Smith's judgement about Newton was not implausible. In Schliesser Citation2003 and Schliesser (forthcoming), I explore the importance of independence (as opposed to Rousseau's emphasis on self-sufficiency) for Smith's and Hume's conception of the philosopher; on that topic, see also Berry Citation1992. 51Mossner 1954: 257 – 8, attributes this claim to Hume: '[in contrast to theology, morals, and politics, which 'will forever propagate disputes'] it is the peculiar happiness of geometry and physics that as they interest less the passions of men, they admit of more calm disquisition and inquiry'. Cf. Hume's Treatise, 1(2):4.24. 52The editors of EPS take Smith to task for this statement. Nevertheless, while Smith's attempt to draw such a disciplinary distinction is somewhat misleading, they ignore the importance of the astronomic engagement with Copernicus to the general philosophic outlook of such luminaries as Stevin, Galileo, Gilbert and Kepler, who were all unusually early Copernicans by end of the sixteenth century; so there is something to Smith's suggestion. For a very provocative book on this topic, see Howard Margolis, Citation2002. 53See Skinner Citation1996: 44. According to Smith, the 'prejudices' of the vulgar, while 'natural', could even corrupt the thinking of Aristotle, the most 'renowned philosopher' ('Ancient Physics' ¶10, 116). Smith is also aware that there can also be national differences in scientific styles and prejudices; in modern times the English invent, while the French methodize. (See 'Letter to the Edinburgh Review', (1756) reprinted in EPS: 244 – 5, ¶5; see also ¶10, 249 – 50.) For further discussion, see Skinner 1966: 26 – 7. 54In 'Considerations Concerning the First Formation of Languages, and the Different Genius of original and compounded Languages' (1761), Smith explains that 'Newton' had become a way of designating a 'philosopher' (¶1, 204, LRBL). The editor of EPS, Wightman, complains about Smith's 'ill-defined terminology', on p. 12. 55The emphasis on the social nature of science is an important part of Smith's reorientation away from Hume (although Treatise, 1(4):1.2, may have been a source of inspiration for Smith). Nevertheless, Frasca-Spada Citation1998: 187 – 93, points out that Hume injects a social component early into the Treatise (e.g. 1(1):7.14 – 15) by focusing on the fact that abstract ideas are the subject of conversation. The mystery of the first Book of the Treatise is why Hume lets the narrator stop interacting with others and end up inside his study. 56In the 'Ancient Logics', Smith writes, '[T]o explain the nature, and to account for the origin of general Ideas is, even at this day, the greatest difficulty in abstract philosophy' (¶5, 125; Smith mentions the works of Locke and Malebranche, but not Hume). Apparently, Smith believes that the theory of ideas is incomplete; it cannot function as an epistemological starting point in understanding the sciences. One may see in this evidence that Smith had not read Hume when he drafted these essays, but no such conclusion needs to be drawn. Hume is also missing in a list of philosophers, which itself seems modelled on Hume's list in the 'Introduction' to Treatise, that made contributions to the study of human nature in 'Letter to the Edinburgh Review', ¶10, 250, EPS; there can be no doubt, however, that Smith had carefully read Hume by 1757 – a mere two years before TMS appeared and close to a decade after Hume and Smith had first met. Moreover, it was Hume, who had most clearly exposed the inadequacies in Locke's and Malebranche's accounts of general Ideas; he had made it appropriate to talk of it as 'even at this day, the greatest difficulty in abstract philosophy'. The reference to 'this day' confirms that Smith was thinking of Hume. 57According to OED, in Smith's time 'direct' can mean to 'guide/lead with advice' or to 'give authoritative instructions'. 58Griswold 1999: 343. 59Fontenelle Citation1728, implies the same in his account of Newton's youthful and momentous discoveries. 60Hume shows how 'imaginary' standards of perfection can 'naturally' be constructed by individuals. Hume's essay, 'Of the Dignity or the Meanness of Human Nature', contains a discussion of several sources for notions of perfection (EMPL: 80 – 6; cf. Treatise 1(2):4.29, for qualifications). See Frasca-Spada Citation1998: 44 – 5, for more discussion. 61It is a very important issue for Smith; see his Letter No. 40 to Sir Gilbert Elliot (Correspondence 49). Brubaker Citation2002 provides an excellent discussion; see also my Schliesser Citation2003. 62Pack Citation1991: 114, implies this; see also the references in note 2 above. 63It also raises a question of how Smith understood his own theoretical activity (see Schliesser, forthcoming). In Schliesser 2005, I argue that Smith differentiates between real and apparent causes (WN I(xi):n.1, 255 – 6). 64Many commentators (e.g. Amadae, Griswold, Lindgren, Skinner, etc.) have noted Smith's claim that the systems of philosophers 'in many respects resemble machines … A system is an imaginary machine' ('Astronomy', IV¶19, 66). Systems are among the products of the philosopher's labour (WN I(1):9, 21 – 2 and V(i):f.26 – 34, 769 – 73). For my views on Smith's use of the machine metaphor, see Schliesser 2005a. 65Skinner Citation1979: 36 n. 24, notes that Smith's judgement echoes d'Alembert's [1963] Citation1995: 79. 66Cf. Smith's Historical truths are now much greater request than they ever were in the ancienttimes. One thing that has contributed to the increase of this curiosity is that there are nowseverall sects in Religion and political disputes which are greatly dependent on the truth of certain facts. (LRBL, Lecture 18( ii):40, 102) 67Newton's Fourth Rule of Reasoning. For the importance of it in Smith, see Schliesser 2005a and Montes forthcoming. 68Mirowski Citation1989: 164, while widely read, is highly misleading when suggesting that Smith wanted to divert our attention away from Newton's action-at-a-distance. Not only does Mirowski quote two passages out of context (in which there is no mention of Newton at all), but he also fails to address the passages in which Smith does discuss Newton's principles! One would never know from Mirowski's account that, besides the passages quoted in the text, Smith also writes ('Astronomy', IV¶67), 'He [Newton] demonstrated, that, if the Planets were supposed to gravitate towards the Sun, and to one another'. 69Schliesser 2005a is devoted to analysing Smith's methodological debts to Newton. For an excellent, parallel treatment, see also Montes Citation2003. 70Smith's first publication, 'Letter to Edinburgh Review', shows a keen awareness of the state of European learning and, late in life, Smith made a concerted effort to obtain back issues of Transactions of the Royal Society (see Letters No.: 239, 276, 294). Smith's collection covered the years 1766 – 88 (see editors' note to Letter No. 239). Smith became a member of the Royal Society in 1767. In LRBL, Lecture 11(i):140 – 1, 57, Smith criticizes Shaftesbury for not keeping up with natural philosophy, and in the 'Astronomy', Cicero, Seneca and Plutarch are named as authors who were largely ignorant of the science of their own time (IV¶18, 65 – 6). 71See Wright Citation1983. 72Cf. George E. Smith Citation2002: 142 – 3. 73I am overstating here. Although Smith clearly (and rightfully) thinks that Newton provides principled, physical reasons for accepting Copernicus, it is not entirely clear what Smith means by this. For an accessible treatment of Newton's argument on this issue, see Di Salle Citation2002: 49 – 51. 74In the same passage, Smith is criticizing Descartes's standards that were widely accepted in the seventeenth century, even by Newton prior to writing the Principia (although not by Kepler). Newton's achievements showed that one need not rest contented with Descartes' criteria. In Schliesser 2005a, I argue that Smith assimilated the import of Newton's 4th Rule of Reasoning. Khalil reads Smith in a very similar fashion. For a very different reading of this passage (and Smith more generally), see Foley Citation1976: 33 and 214 n.70. 75The Pyrrhonian Skeptic is not argued against. It may seem as if Smith is merely adopting Hume's position. After all, Hume was willing to grant that, on the level of feelings, even a skeptic had to remain a realist; but Hume had attempted to restrict the domain of this assent to experiences of common life; Hume's 'mitigated skeptic' can remain skeptical about adopting the theories of the natural philosophers when they attempt to go beyond common life by, for instance, introducing abstract entities. 76One could see Smith as arguing that the 'familiar principle of connection' explains why Newton's theory was eventually widely accepted; but this ignores Smith's comments on Cassini's observations. 77Cropsey Citation1957: 46. 78D'Alembert [1963] Citation1995, 127. Cf. p. 96, where d'Alembert seems to be implying that geometry, astronomy, and mechanics are never-ending due to 'their nature'. 79See Skinner Citation1979: 24. Daston and Park Citation1998 miss this about Smith's account. 80The editors of EPS point to Plato's Theaetetus (155D) and Aristotle's Metaphysics, A (982b11 – 24). 81See Howard Stein 1988 and Stein forthcoming. For Smith's Platonism, see Griswold, passim. 82See 'Epistemology Naturalized' in Quine Citation1969.