I would like to thank J. E. McGuire and L. L. Laudan for their invaluable help and encouragement in the development of the views expressed in this paper.

¹ All of Priestley's electrical publications appeared in the five years prior to 1772, after which his scientific interests became dominated by chemical problems. See (i) The history and present state of electricity with original experiments, London, 1767Google Scholar. Subsequent references will be to the History of electricity; (ii) ‘An account of rings consisting of all the prismatic colours, made by electrical explosions on the surface of pieces of metal’, Philosophical transactions, 1768, 58, 68–74Google Scholar; (v) ‘Experiments on the lateral force of electrical explosions’, Philosophical transactions, 1769, 59, 57–62Google Scholar; (iv) ‘Various experiments on the force of electrical explosions’, Philosophical transactions, 1769, 59, 63–70Google Scholar; (v) ‘An investigation of the lateral explosion, and of the electricity communicated to the electrical circuit, in a discharge’, Philosophical transactions, 1770, 60, 192–210Google Scholar; (vi) ‘Experiments and observations on charcoal’, Philosophical transactions, 1770, 60, 211–27Google Scholar; (vii) A familiar introduction to the study of electricity, London, 1768 (2nd edn., London, 1769).Google Scholar

² Hartog, P., ‘Newer views of Priestley and Lavoisier’, Annals of science, 1941, 5, 1–56 (9).CrossRefGoogle Scholar

³ Ibid., pp. 8, 13.

⁴ See Schofield, R. E., ‘Electrical researches of Joseph Priestley’, Archives internationales d'histoire des sciences, 1963, 16, 277–86Google Scholar (277, n. 2), where this lamentable state of affairs is duly noted.

⁵ Schofield, R. E., ‘Joseph Priestley, natural philosopher’, Ambix, 1968, 15, 7Google Scholar. He is here quoting from Newton, I., Mathematical principles of natural philosophy, Florian Cajori's revision of Andrew Motte's translation, Berkeley, 1967, pp. xvii–xviiiGoogle Scholar. See also ‘The scientific background of Joseph Priestley’, Annals of science, 1957, 13, 148Google Scholar. The traditional view of Priestley's science has a long history. More recent representatives of it are Holt, A., A life of Joseph Priestley, London, 1931Google Scholar; Lodge, O., Nine famous Birmingham men, Birmingham, 1909Google Scholar; Partington, J. R., A history of chemistry, 4 vols., London, 1962–, iii, 237–97CrossRefGoogle Scholar; Thorpe, T. E., Joseph Priestley, London & New York, 1906.Google Scholar

⁶ This ‘mechanistic’ interpretation of Priestley's chemistry is most fully stated and developed by Schofield in ‘Joseph Priestley, natural philosopher’, op. cit. (5), pp. 1–15Google Scholar. Various aspects of the argument presented here are repeated by Schofield in a number of other places. See, e.g. (i) ‘Boscovich and Priestley's theory of matter’, in Whyte, L. L. (ed.), Roger Joseph Boscovich SJ, FRS, 1711–87, London, 1961, pp. 168–72Google Scholar; (ii) ‘Joseph Priestley, the theory of oxidation and the nature of matter’, Journal of the history of ideas, 1964, 25, 285–94Google Scholar (see especially pp. 292–6); (iii) A scientific autobiography of Joseph Priestley, 1733–1804, Cambridge, Mass., 1966, pp. 134–7, 195–7, 273–5Google Scholar; (iv) Mechanism and materialism: British natural philosophy in an age of reason, Princeton, 1970, pp. 269–73Google Scholar. The consequences of this view for Priestley's electrical thought are spelled out in ‘Boscovich and Priestley's theory of matter’, op. cit. (6, i), pp. 168–9Google Scholar; ‘Electrical researches of Joseph Priestley’, op. cit. (4), pp. 283–4Google Scholar; ‘Joseph Priestley, the theory of oxidation and the nature of matter’, op. cit. (6, ii), pp. 292–4Google Scholar; Mechanism and materialism, op. cit., (6, iv), pp. 261–3Google Scholar. No mention is made of this view in Schofield's other major work on Priestley: (v) The Lunar Society of Birmingham: a social history of provincial science and industry in eighteenth-century England, Oxford, 1963Google Scholar. This mechanistic view of Priestley is taken up in Lindsay, J. (ed.), Autobiography of Joseph Priestley: memories written by himself, Bath & Cranbury, NJ, 1970Google Scholar, and Thackray, A., Atoms and powers, Cambridge, Mass., 1970.CrossRefGoogle Scholar

⁷ ‘Joseph Priestley, natural philosopher’, Op. cit. (5), p. 7Google Scholar. Similar sentiments are expressed in ‘Boscovich and Priestley's theory of matter’, op. cit. (6, i), p. 169Google Scholar. Schofield's claim is weakened even further in Mechanism and materialism, op. cit. (6, iv), p. 265Google Scholar (see also p. 262). Here, we are told that ‘matter theory alone’ cannot provide ‘an explanation by which all’ of Priestley's ‘experiments can be coordinated’. Instead, it merely serves to lend order to the more ‘diverse’ or ‘anomalous’ aspects of his experimentation. However, Schofield abandons even this weaker claim when he attempts a sustained analysis of Priestley's electrical thought: in ‘Electrical researches of Joseph Priestley’, op. cit. (4)Google Scholar, he makes no attempt to relate Priestley's experiments to his ‘mechanistic’ interests, lapsing instead into a straightforward positivistic description of Priestley's electrical work. It thus appears that there is little or no historical substance to Schofield's ‘mechanistic’ interpretation of Priestley's electrical thought.

⁸ See McEvoy, J. G., ‘Joseph Priestley, natural philosopher: some comments on Professor Schofield's views,’ Ambix, 1968, 15, 115–33Google Scholar. Although this criticism deals exclusively with ‘Joseph Priestley, natural philosopher’, op. cit. (5), it also applies to the rest of Schofield's publications to the extent that they reiterate the views expressed in that article (see note 6 above).

⁹ See pp. 18–19 below.

¹⁰ Historical studies in the physical sciences, 1975, 6, 325–404Google Scholar. For an application of this intellectual framework to Priestley's work on ‘gases’, the reader is referred to McEvoy, John G., ‘Joseph Priestley, “aerial philosopher”: metaphysics and methodology in Priestley's chemical thought, from 1772 to 1781’, Part I, Ambix, 1978, 25, 1–55CrossRefGoogle Scholar; Part II, ibid., pp. 93–116; Part III, ibid., pp. 153–75; Part IV, Ambix, 1979, 26Google Scholar, forthcoming. A future study will apply these conceptual parameters to his debate with ‘the Lavoisians’, but for the moment the reader is referred to McEvoy, John G., Joseph Priestley: philosopher, scientist, and divine, PhD dissertation, University of Pittsburgh, 1976 (University Microfilms, 76–8812).Google Scholar

¹¹ See (i) Priestley, J., A free discussion of the doctrines of materialism and philosophical necessity in a correspondence between Dr Price and Dr Priestley, London, 1778Google Scholar, in Rutt, J. T. (ed.), The theological and miscellaneous works of Joseph Priestley, LLD, FRS, 25 vols., London, 1817–1835, iv, 143Google Scholar (Hereafter, Works), where he claims that Scripture contains nothing either paradoxical or ‘contrary to natural appearances’; (ii) Disquisitions relating to matter and spirit, 2nd edn., London, 1782Google Scholar, in Works, op. cit. (11, i), iii, 220Google Scholar where he claims that ‘the three Doctrines of materialism… Socinianism and of philosophical necessity, are equally parts of one system, being equally founded on just observations of nature, and fair deductions from the Scriptures:…’ Now it has to be noted that Priestley did not fully articulate this system of thought until 1774, when he explicitly adopted the doctrine of materialism. Although this occurred almost four years after his last electrical publication, it in no way undermines our attempt to relate his work in electricity to the totality of his thought. In the first place, the conceptual ingredients that concern us (Socinianism, determinism, associationism) were all clearly present in Priestley's mind by the time of his first publication in electricity (see notes 13, 14, 18, 36 below). What is more, Priestley's -acquiescence in the traditional dualism prior to 1774 does not signify a crucial break in his conceptual career; but merely reflects his early neglect of the relevant metaphysical issues (See Ibid., pp. 200–01). When he did turn his attention to the body-mind problem, however, lie found that the doctrine of materialism facilitated a more consistent representation of the rest of his views (see McEvoy, J. G. and McGuire, J. E., op. cit., (10), pp. 380–4).Google Scholar

¹² See Priestley, J., Letters to a philosophical unbeliever, Birmingham, 1787Google Scholar, in Works, op. cit. (ii, i), iv, 446Google Scholar, where he says, ‘Christianity will be no obstruction to anything that is truely rational, and becoming a man, with respect to either, and whatever is not rational ought to be abandoned on grounds that are not even Christian’.

¹³ In making this rather bald statement any attempt to relate Priestley's thought to its proper theological context has been delegated to another study. Such an analysis will have to deal with the development of Priestley's theism from the gloomy voluntarism of his Calvinist youth to his conversion, in 1767, to the rational optimism of Socinianism (see Memoirs of Joseph Priestley to the year 1795, written by himself, London, 1806Google Scholar, in Works, op. cit. (11, i), i, 5–26, 30–7, 58–69Google Scholar). A complete picture would involve a detailed biographical study of his years at Daventry Academy, Needham Market, Nantwich and Warrington. Some suggestive hints concerning the parameters relevant in such an enquiry can be found in McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 329–37Google Scholar and in Schofield, R. E., Mechanism and materialism, op. cit. (6, iv), pp. 264–5Google Scholar. For tne moment, it is necessary to emphasize the importance of David Hartley in this and other contextual issues relating to the origins and development of Priestley's thought. According to Priestley himself, he was ‘more indebted to “Hartley's Observations on Man” than to all the books I have ever read beside, the scriptures excepted’: An examination of Dr Reid's inquiry into the human mind on the principles of commonsense, etc., in Works, op. cit. (11, i), iii, 10Google Scholar. The present study will give ample testimony to the truth of this claim (see also, McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10)).Google Scholar

¹⁴ See (i) Priestley, J., Institutes of natural and revealed religion, 2nd edn., 2 vols., Birmingham, 1782Google Scholar, in Works, op. cit. (11, i), ii, 5Google Scholar. First published in 1772, Priestley composed the first draft of this treatise in 1755 (See, e.g. Memoirs, op. cit. (13), pp. 27, 30)Google Scholar. His manuscript was an integral part of his religious life for the next fifteen years, forming the basis of many of his lectures and sermons (See, e.g. Ibid., pp. 30, 125, 154). It thus gives us an excellent expression of Priestley's theistic interests and views during the period (1767–1772) that concerns us. See ako (ii) History of electricity, op. cit. (1), pp. iii–ivGoogle Scholar; (iii) Experiments and observations on different kinds of air, 3 vols., London, 1774–1777, i vii–viii.Google Scholar

¹⁵ Institutes, op. cit. (14), pp. 5, 11, 17.Google Scholar

¹⁶ Ibid., p. 6: See also notes 54 and 55 below.

¹⁷ Ibid., pp. 12–14.

¹⁸ The doctrine of philosophical necessity illustrated, being an appendix to the disquisitions relating to matter and spirit, 2nd edn., London, 1782Google Scholar, in Works, op. cit., (11, i), iii, 454–5Google Scholar. See also Philosophical unbeliever, op. cit. (12), p. 347Google Scholar. Priestley was strongly attached to his deterministic view of the world (see Philosophical necessity, op. cit. (18), 454Google Scholar); and he first became acquainted with it while at the Daventry Academy (1752–1755), when he read Collin, Anthony's A philosophical inquiry concerning human liberty, London, 1715Google Scholar. His subsequent reading of ‘Dr Hartley's observations on man’ further confirmed him in this belief (see Memoirs, op. cit. (13), p. 24Google Scholar. See also McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 341–2Google Scholar for a short outline of the tradition of thought within which Priestley's determinism should be located).

²⁹ See pp. 7–10, 15 below. It should be noted that although we have, here, presented determinism as a deductive consequence of Priestley's theism, the exact nature of the relation between these two aspects of his thought is a more subtle and less straightforward affair that needs to be explored in more detail elsewhere (see, e.g. McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 337–41Google Scholar). The aim of this presentation is to emphasize the intimate relation between Priestley's determinism and his view of the benevolent structure of reality. Thus we ‘are links in a great connected chain, parts of an immense whole’ which ‘is under an unerring direction’ that guarantees that ‘the final result will be most glorious and happy’: (Philosophical necessity, op. cit. (18), p. 450).Google Scholar

²⁰ See e.g. Philosophical necessity, op. cit. (18), pp. 507, 518Google Scholar; An essay on the first principles of government and on the virtue of political, civic and religious liberty, London, 1768, pp. 2–3Google Scholar. Once again the influence of Hartley prevails over Priestley's thinking, as can be seen by comparing Hartley, David, Observation on man, his frame, his duty and his expectations, 2 vols., London, 1749, i, 114Google Scholar. For a fuller discussion of the interaction between Priestley's theism and natural philosophy the reader is referred to McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 342–48.Google Scholar

²¹ See History of electricity, op. cit., (1), p. xxiGoogle Scholar. Essay on government, op. cit. (20), pp. 2–3Google Scholar. Compare this with Hartley, David, Observations on man, op. cit. (20), i, 82Google Scholar. See also An examination of Dr Reid's inquiry into the human mind on the principles of commonsense; Dr Beattie's essay on the nature nad immutability of truth; and Dr Oswald's appeal to common sense on behalf of religion, London, 1774Google Scholar, in Works, op. cit. (11, i), iii, 94.Google Scholar

²² The History of electricity, p. xxGoogle Scholar. This viewpoint was a commonplace among eighteenth-century natural philosophers. See e.g. Newton, I., Opticks, 4th edn., London, 1730 (reprinted New York, 1952), p. 405Google Scholar; Maclaurin, C., Account of Sir Isaac Newton's philosophical discoveries, London, 1758, p. 4Google Scholar; Derham, W., Physico-theology, London, 1713Google Scholar; Hartley, D., Observations on man, op. cit. (20), ii, 45.Google Scholar

²³ See, e.g. Philosophical necessity, op. cit. (18), p. 451.Google Scholar

²⁴ Experiments and observations relating to various branches of natural philosophy, 3 vols., London, 1779–1786, ii, viii–ix.Google Scholar

²⁵ See, e.g. Air, op. cit. (14, iii), i, vii.Google Scholar

²⁶ See pp. 9–10 below.

²⁷ Natural philosophy, op. cit. (24), ii, ixGoogle Scholar. See also Air, op. cit. (14, iii), i, viii.Google Scholar

²⁸ History of electricity, op. cit. (1), pp. ii–iii.Google Scholar

²⁹ Ibid., p. iv.

³⁰ Ibid., pp. iii–iv.

³¹ Ibid., pp. v–vi.

³² Ibid., pp. vii–xiii. Such an intellectual climate undoubtedly guaranteed a ready market for the History of electricity, without which it would have been economically impossible for Priestley to have pursued his career in the history of science (see Memoirs, op. cit. (13), pp. 57, 77–8)Google Scholar. Although this study ignores the wider social context of Priestley's intellectual life, a full understanding of his thought and the products thereof must relate it to the material circumstances in which he lived.

³³ See ‘The Contents’, Ibid., pp. xxiv–xxvii.

³⁴ As will be discussed below (p. 14) such an emphasis on ‘experiment and discovery’ is further reinforced by Priestley's epistemological egalitarianism, which opposes the ‘synthetic’ emphasis on the role of preconceived theory in natural philosophy in favour of the ‘analytic and historical’ account of the way in which ‘discoveries have actually been made’.

³⁵ Ibid., p. 194.

³⁶ Priestley first read Locke, John's, An essay on human understanding in 1751Google Scholar (See Memoirs, op. cit. (13), p. 13Google Scholar). Discussions of this tradition are to be found in Buchdahl, G., The image of Newton and Locke in the age of reason, London and New York, 1961Google Scholar; Cassirer, E., The philosophy of the Enlightenment, trans, by Hoeling, F. C. A. and Pettigrove, J. F., Boston, 1962, pp. 93–133Google Scholar; Hazard, P., The European mind, 1680–1715, Harmondsworth, 1964, pp. 277–90Google Scholar; SirStephens, L., English thought in the eighteenth century, 3rd edn., London, 1927, pp. 34–58.Google Scholar

³⁷ See An examination, op. cit. (21), pp. 15–24Google Scholar; Priestley, J., Hartley's theory of the human mind on the principle of association of ideas, with essays relating to the subject of it, 2nd edn., London, 1790Google Scholar, in Works, op. cit. (11, i), iii, 168–200Google Scholar; History of electricity, op. cit. (1), pp. 441–2.Google Scholar

³⁸ See An examination, op. cit. (21), pp. 15–24Google Scholar; Miscellaneous observations relating to education more especially as it respects the conduct of the mind, London, 1778Google Scholar in Works, op. cit. (11, i), xxv, 19Google Scholar. The sources of this tradition are to be found in Laudan, L. L., ‘Theories of scientific method from Plato to Mach: a bibliographical review’, History of science, 1968, 7, 24–8.CrossRefGoogle Scholar

³⁹ Priestley's Lockean views are most fully expressed and discussed in An examination, op. cit. (21), pp. 15–24Google Scholar, and in Hartley's theory of the mind, op. cit. (37), pp. 168–200Google Scholar. On the matter under discussion in the text, these sources should be compared and contrasted with Locke, John, An essay concerning human understanding, ed. by Fraser, A. C., 2 vols., New York, 1959, i, 159, 527–35Google Scholar. See also Cassirer, E., Enlightenment, op. cit. (36), pp. 99–100Google Scholar for a further discussion of this reductionist programme. See also McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 348–57Google Scholar for a fuller discussion of Priestley's associationism.

⁴⁰ See, e.g. Hartley's theory of the mind, op. cit. (37), pp. 183–96.Google Scholar

⁴¹ See, e.g. An examination, op. cit. (21), pp. 18–9.Google Scholar

⁴² Philosophical unbeliever, op. cit. (12), pp. 401–02.Google Scholar

⁴³ Letter to the author of the letters on materialism and on Hartley's theory of the mind, London, 07 1977Google Scholar, in Works, op. cit. (n, i), iv, 127–8.Google Scholar

⁴⁴ An examination, op. cit. (21), iii, 70.Google Scholar

⁴⁵ Philosophical unbeliever, op. cit. (12), p. 327Google Scholar; An examination, op. cit. (21).Google Scholar

⁴⁶ An examination, op. cit. (21), p. 125Google Scholar. See also pp. 15–17; Philosophical unbeliever, op. cit. (12), pp. 328–9Google Scholar. The influence of David Hartley is once again very evident, as can be seen by an examination of Observations on man, op. cit. (20), i, 325–79.Google Scholar

⁴⁷ An examination, op. cit. (21), pp. 15–16Google Scholar. See also Philosophical unbeliever, op. cit. (12), p. 329Google Scholar. Although it is beyond the scope of this study, it should nevertheless be noted that Priestley was well aware of Hume's criticisms of ‘natural necessity’, and sought to meet the sceptical challenge in a number of ways (see, e.g. McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 363–7)Google Scholar. Viewing Hume as attempting to reduce causal arguments to ‘an arbitrary and perhaps ill-founded association of ideas’, Priestley defended the thesis that ‘the idea of power or causation’ is ‘an idea that all men have and corresponds to something real in the relation of the things that suggest it.’ (Philosophical unbeliever, op. cit. (12), p. 399).Google Scholar

⁴⁸ Philosophical unbeliever, op. cit. (12), p. 403.Google Scholar

⁴⁹ Philosophical necessity, op. cit. (18), p. 455.Google Scholar

⁵⁰ Institutes, op. cit. (14), p. 5Google Scholar. See also text at p. 3 above.

⁵¹ Philosophical necessity, op. cit. (18), p. 462Google Scholar. See also Institutes, op. cit. (14), pp. 7–14.Google Scholar

⁵² An examination, op. cit. (21), p. 127.Google Scholar

⁵³ See Institutes, op. cit. (14), p. 12.Google Scholar

⁵⁴ See, History of electricity, op. cit. (1), p. 442Google Scholar; Hartley's theory of the mind, op. cit. (37), p. 185Google Scholar‘Observations and experiments relating to equivocal or spontaneous generation’, American philosophical transactions, 1809, 6, 129Google Scholar. See also McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 368–74Google Scholar, for a fuller discussion of this aspect of Priestley's thought.

⁵⁵ History of electricity, op. cit. (1), pp. 441–2.Google Scholar

⁵⁶ Natural philosophy, op. cit. (24), ii, vii.Google Scholar

⁵⁷ Hartley's theory of the mind, op. cit. (37), p. 185.Google Scholar

⁵⁸ This identification of ‘fact’ with ‘particular’ or ‘general’ proposition in Priestley's thought has its textual basis in the ease with which he substitutes one for the other in statements of synonymous epistemological intent (Compare, e.g. notes 46, 47, 56, 57 above. See also Natural philosophy, op. cit. (24), iii, xxiiGoogle Scholar where he talu about ‘a theory, or system of principles, to which all the facts may be reduced’). More importantly, however, such an identification is essential in the epistemological grounding of Priestley's methodological commitments, which must not be viewed in isolation if the systematic nature of his thought is to be appreciated.

⁵⁹ Examples of this linguistic distinction are to be found at History of electricity, op. cit. (1), p. 8, 90–1, 108–10, 114, 185, 190, 211, 237–45, 251–9, 344, 274–8, 393–4, 430.Google Scholar

⁶⁰ See Ibid, pp. 170–80, 353.

⁶¹ See Ibid., pp. 150, 467. For a discussion of Franklin's electrical thought, the reader is referred to Cohen, I. B., Franklin and Newton, Philadelphia, 1956.Google Scholar

⁶² See Ibid., pp. 433–4.

⁶³ Ibid., pp. 434–5.

⁶⁴ Ibid., pp. 435–9. This rigorous epistemological distinction between ‘fact’ and ‘hypothesis’ is still evident in the lectures on electricity that Priestley delivered at the Hackney Academy in 1794. (See Heads of lectures on a course of experimental philosophy, London, 1794, pp. 162–80).Google Scholar It must also be remembered that Priestley was immersed in his famous debate with ‘the Lavoisians’ at this time. It, therefore, follows that the extension of the analytical framework developed in this paper to this crucial episode in the history of science requires the rejection of that well-worn historiographical prejudice, according to which Priestley's ‘dogged’ adherence to the ‘erroneous’ phlogiston theory blinded him to the superior merits of Lavoisier's position (See McEvoy, J. G., ‘Joseph Priestley, “aerial philosopher”’, op. cit. (10), Part I, pp. 1–5Google Scholar, for an outline of this impoverished historiography. See McEvoy, J. G., Joseph Priestley: philosopher, scientist, and divine, op. cit. (10)Google Scholar, for a discussion of this episode in Priestley's scientific career in terms of the conceptual matrix outlined in this paper.

⁶⁵ An examination, op. cit. (21), p. 74.Google Scholar

⁶⁶ Beattie, J., Essay on the nature and immutability of truth, in opposition to sophistry and scepticism, Birmingham, 1771, p. 45.Google Scholar

⁶⁷ For a fuller discussion of Priestley's evaluation of the commonsense philosophy the reader is referred to McEvoy, J. G. and McGuire, J. E., op. cit. (10), pp. 357–61, 374–80Google Scholar. (See especially p. 367 for the source of Priestley's distorted view of the subjectivist tendencies of commonsense). An examination, op. cit. (21)Google Scholar presents the fullest account of Priestley's reaction to the views of Reid, Oswald and Beattie. An expression of the concern for liberty and equality that Priestley overlooked among these thinkers can be found at Beattie, J., Essays on the nature and immutability of truth in opposition to sophistry and scepticism. On poetry and music as they affect the mind. On laughter and ludicrous composition. On the utility of classical learning, Edinburgh, 1776, p. 343.Google Scholar

⁶⁸ An examination, op. cit. (21), pp. 76, 101–02.Google Scholar

⁶⁹ Air, op. cit. (14, iii), i, xivGoogle Scholar. For a discussion of the political, social and educational struggles of eighteenth century dissenters, and Priestley's role therein, the reader is referred to Barlow, R. B., Citizenship and conscience, Philadelphia, 1962CrossRefGoogle Scholar; Cowherd, R. G., The politics of English dissent, 1815 to 1834, Philadelphia, 1942Google Scholar; Henriques, U., Religious toleration in England, 1787–1833, Toronto, 1961Google Scholar; Hunt, N. C., Two early political associations: the Quakers and the dissenting deputies in the age of Sir Robert Walpole, Oxford, 1961Google Scholar; Lincoln, A., Some political and social ideas of English dissent, 1763–1800, Cambridge, 1938Google Scholar; McLachlan, H., English education under the Test Acts, Manchester, 1931Google Scholar; Schofield, R. E., The Lunar Society, op. cit. (6, v).Google Scholar

⁷⁰ See pp. 16–17 below.

⁷¹ History of electricity, op. cit. (1), p. viGoogle Scholar. See also the History of vision, i, xiGoogle Scholar. (For the fuller title of this work see text and note 73 below.) See Cohen, I. B., Franklin and Newton, op. cit. (61)Google Scholar for a discussion of the Baconian tradition. Priestley held Bacon in high esteem and had a copy of his works in his library (See Air, op. cit. (14, iii), ii, xvii).Google Scholar

⁷² See, e.g. A description of a chart of biography, Warrington, 1763, p. IGoogle Scholar. See also The history of vision, op. cit. (71), i, iv.Google Scholar

⁷³ 2 vols., London, 1772.Google Scholar

⁷⁴ Memoirs, op. cit. (13), p. 78.Google Scholar

⁷⁵ History of electricity, op. cit. (1), p. 574Google Scholar. As I. B. Cohen has pointed out, Priestley is, here, giving expression to the ‘two Newtonian methods’ that dominated eighteenth-century natural philosophy (Franklin and Newton, op. cit. (61), p. 190)Google Scholar. Many thinkers—including Pemberton, MacLaurin, Voltaire and Diderot—sought to offset the image of science as a product of awesome genius that was conveyed by the severely ‘synthetic’ style of the Principia. The product was a ‘series of splendid vulgarizations’ (Ibid., p. 123) and an emphasis on the more speculative, experimental, Opticks. Priestley uses, and endorses, this tradition in order to grind his own epistemological and methodological axe.

⁷⁶ History of electricity, op. cit. (1), pp. 576–7.Google Scholar

⁷⁸ See note 34 above, and the relevant text.

⁷⁸ An examination, op. cit. (21), p. 25.Google Scholar

⁷⁹ History of electricity, op. cit. (1), pp. 443–4.Google Scholar

⁸⁰ Ibid., pp. 443–6.

⁸¹ Priestley was one of the first eighteenth-century natural philosophers to recognize the importance of hypothetical reasoning in science. This important fact could be obscured by the correct claim that few eighteenth-century scientists were discouraged from hypothesizing by Newton's famous ‘dictum’ about hypotheses (see, e.g. Cohen, I. B., Franklin and Newton, op. cit. (61), pp. 348–52.)Google Scholar This may be true; but it is beside the point. For many of these scientists still expressed the anti-hypothetical, narrowly inductive methodology of Newton, and showed no understanding of the logical status and epistemological function of hypotheses in natural philosophy. Priestley, in the manner of his great mentor Hartley, opposed this tradition in theory as well as practice (see, e.g. Laudan, L. L., ‘Theories of scientific method’, op. cit. (38), pp. 24–8)Google Scholar. These developed methodological sensibilities were an important factor in shaping Priestley's natural philosophy as part of his totalistic philosophy of nature.

⁸² History of electricity, op. cit. (1), p. 444.Google Scholar

⁸³ Ibid., pp. 443–4. See also p. 15 above.

⁸⁴ Ibid., 444. See also note 82 above.

⁸⁵ See Priestley, J., An examination, op. cit. (21), p. 16Google Scholar. These different senses of analogy are numbered in reverse order to their appearance in the text, in order to maintain consistency with other studies where they are discussed more fully (see e.g. McEvoy, J. G., ‘Joseph Priestley, “aerial philosopher”’, op. cit. (10), Part I.Google Scholar

⁸⁶ For example, Priestley explicitly refers to hypotheses as guesses at the system of the world that ‘may be some guide to us in the discovery of the facts’ (see text on p. 24 below).

⁸⁷ Natural philosophy, op. cit. (24), iii, xii–xiii.Google Scholar

⁸⁸ History of electricity, op. cit. (1), pp. 446–7.Google Scholar

⁸⁹ See p. 11 above.

⁹⁰ History of electricity, op. cit. (1), pp. 450–4Google Scholar. See also, ibid., pp. 27, 120–1, 140, for other examples of this epistemological distinction in Priestley's historical narrative.

⁹¹ Ibid., pp. 108–9, 159, 204, 237, 373. Priestley's epistemological classification of Franklin's theory as a mere ‘hypothesis’ serves to diminish the Franklinian tone that many of his contemporaries and commentators claim to detect in the History of electricity (see, e.g. Cohen, I. B., Franklin and Newton, op. cit. (61))Google Scholar. The presence of any such bias in Priestley's narrative derives from the methodological priority that he gave to Franklin's theory, as well as from his occasional, but self-critical, lapses from epistemological purity (see also note 114 below).

⁹² Ibid., pp. 468–78.

⁹³ Ibid., pp. 480–1, 484–6.

⁹⁴ Ibid., p. 500.

⁹⁵ Ibid., pp. 500–1.

⁹⁶ Ibid., p. 502.

⁹⁷ Ibid., p. xiii.

⁹⁸ ‘Joseph Priestley, natural philosopher’, op. cit. (5), pp. 3–4.Google Scholar

⁹⁹ Disquisitions, op. cit. (11, ii), pp. 237–8Google Scholar. See also McEvoy, J. G. and McGuire, J. E., ‘God and nature’, op. cit. (10), pp. 387–93.Google Scholar

¹⁰⁰ Heimann, P. M., ‘Nature is a perpetual worker: Newton's aether and eighteenth-century natural philosophy’, Ambix, 1973, 20, 1–25.CrossRefGoogle Scholar

¹⁰¹ History of electricity, op. cit. (1), pp. 573, 575, 579.Google Scholar

¹⁰² Ibid., pp. 591–7.

¹⁰³ Ibid., pp. 635–41.

¹⁰⁴ ‘An investigation of the lateral explosion’, op. cit. (2, v), p. 204.Google Scholar

¹⁰⁵ History of electricity, op. cit. (1), pp. 581–4.Google Scholar

¹⁰⁶ Ibid., pp. 611–4.

¹⁰⁷ Ibid., pp. 673–84.

¹⁰⁸ Ibid., pp. 584–90.

¹⁰⁹ Ibid., pp. 697–713.

¹¹⁰ Op. cit. (2, ii), pp. 57–60.Google Scholar

¹¹¹ History of electricity, op. cit. (1), pp. 653–71.Google Scholar

¹¹² Ibid., pp. 685–9.

¹¹³ Ibid., p. 669.

¹¹⁴ See ‘An account of the rings consisting of all the prismatic colours’, op. cit. (1, ii)Google Scholar. The reader may naturally wonder how Priestley's redescription of these phenomena in terms of Newton's theory relates to his dominant epistemological interest in the separation of ‘fact’ from ‘hypothesis’. Two replies would be possible. Priestley could simply admit, as he does on other occasions (e.g. Air, op. cit. (14, iii), ii, 29–30Google Scholar) that he has failed to live up to his methodological precepts; on the other hand, his classification of this phenomenon as optical rather than electrical could be distinguished, as ‘fact’, from his hypothetical explanation of their production by the ‘vitreous parts’ of the metal. Either way, his methodological priorities are not impugned by this incident.

¹¹⁵ History of electricity, op. cit. (1), pp. 714–33.Google Scholar

¹¹⁶ See ‘An investigation of the lateral explosion’, op. cit. (1, v), p. 193.Google Scholar

¹¹⁷ History of electricity, op. cit. (1), pp. 598–601.Google Scholar

¹¹⁸ Ibid., pp. 601–2.

¹¹⁹ Op. cit. (1, iv). See also History of electricity, op. cit. (1), pp. 609–20.Google Scholar

¹²⁰ ‘Experiments and observations on charcoal’, op. cit. (1, vi), p. 214.Google Scholar

¹²¹ Ibid., pp. 218–9.

¹²² Ibid., p. 220.

¹²³ Ibid., pp. 224–5.

¹²⁴ Ibid., p. 227.

¹²⁵ History of electricity, op. cit. (1), pp. 579–80.Google Scholar