This chapter sets out the origins of the traditional historiography of early modern philosophy based on the dichotomy of empiricism and rationalism. After reconstructing the spread of the notions of empiricism and rationalism in Germany during the 1780s, we argue that the first outline of a history of metaphysics that displays the Kantian, epistemological, and classificatory biases can be found in Karl Leonhard Reinhold’s works from the early 1790s. Two early Kantian historians, Wilhelm Gottlieb Tennemann and Johann Gottlieb Buhle, turned Reinhold’s outline into fully fledged histories of early modern thought. Tennemann, who became a Kantian after reading Reinhold’s works, developed Reinhold’s historical sketches into a detailed, nuanced, and comprehensive account of seventeenth- and eighteenth-century philosophy that revolves around the empiricism/rationalism distinction and displays the biases of the traditional historiography. Thus, in Germany, the decline of experimental philosophy and the eclipse of the experimental/speculative distinction went hand in hand with the rise of Kantianism and the development of a historiography based on the empiricism/rationalism distinction.

This chapter examines the impact of experimental philosophy in France from the mid-1730s through to the period in which the philosophes were at the forefront of French intellectual life, the period normally called the French Enlightenment. The chapter opens with a discussion of the reception of Bacon’s views about natural history and the acceptance of experimental philosophy more generally in the early Parisian Academy. It then turns to the heyday of experimental philosophy in France which began in the mid-1730s with its promotion by the likes of Voltaire and Comte de Buffon, and the courses in experimental philosophy taught by Abbé Nollet. It is argued that the anti-speculative sentiment so prevalent in Britain manifests itself in the anti-system debate in France. And the chapter goes on to examine the alignment between Buffon’s conception of natural history and that of Bacon, the Baconianism of Denis Diderot, and the influence of experimental philosophy on Jean Le Rond d’Alembert as manifest in his ‘Preliminary Discourse’ to the Encyclopédie. The chapter concludes with an appraisal of the rehabilitation of Descartes, who up to that point had come to be regarded by many as the archetypal speculative philosopher.

After summarising our findings in the preceding chapters, the Conclusion assesses the relative merits of experimental philosophy and empiricism as historiographical categories, and in the process we respond to some of our critics. We examine the historicity of both notions, their disciplinary and chronological scope, their contrast classes, namely, speculative philosophy and rationalism, and their explanatory power. Through an examination of the anti-hypotheticalism so prevalent in the early modern period and Margaret Cavendish’s published critique of experimental philosophy, we argue that experimental philosophy, together with the experimental/speculative distinction, have more explanatory power than the rationalism/empiricism distinction.

The Introduction provides the rationale for the writing of a history of early modern experimental philosophy and introduces the book’s major themes. It opens with a discussion of the meaning of the term ‘experimental philosophy’ and explains how it should be differentiated from contemporary x-phi and the historiographical category of empiricism. We claim that ‘experimental philosophy’ initially referred to a method for acquiring knowledge of nature that prioritises observation and experiment over theory, but it soon became the referent for the movement of experimental philosophers – as its practitioners called themselves – and for the actual knowledge acquired by this method. The Introduction then sets out some of the broader philosophical context in which experimental philosophy emerged, including the role of principles, the two-step approach to developing a science of nature, the experimental/speculative distinction, its employment of a form of natural history deriving from Francis Bacon, and a clutch of philosophical problems that impinged on this new approach to knowledge acquisition. These include the problems of how we get epistemic access to the essences of material things, how to articulate the precise relationship between experiment and observation on the one hand and theory on the other, and the roles of natural history and mathematics in experimental natural philosophy. The Introduction concludes with a summary of each chapter of the book.

This chapter turns from France to Scotland and from natural philosophy to moral philosophy. Through an examination of a number of leading Scots moral philosophers, we examine the impact of experimental philosophy on the project of the science of man in the Scotland of the eighteenth century. While it is incorrect to speak a movement of experimental moral philosophy in eighteenth-century Scotland, the impact of this new approach to natural philosophy is evident in its critique of speculation and hypotheses, in the roles that moral philosophers accorded to experiment and observation, in the rudimentary philosophy of experiment found in the writings of David Hume, and in the attempts by Scottish moral philosophers, such as George Turnbull, to apply the method of natural history and to incorporate analogues of physical laws in their theories. This chapter provides us with ample evidence for the claim that experimental philosophy had a decisive impact on the development of Scottish moral philosophy of the eighteenth century.

This chapter explains the nature of Baconian natural history and the philosophy of experiment that came to be associated with it in the late seventeenth century. It also documents the practice of this form of natural history in the early Royal Society and beyond. Baconian or experimental natural history is first set in contrast to classificatory natural history which focused on natural kinds. It was an architectonic program of experiment and fact gathering and fact ordering with a view to discovering the principles of the particular science at hand. Its subject matter ranged from celestial objects to the sea bed, from bodies, states of bodies, and qualities to natural processes. We then discuss the philosophy of experiment associated with this form of natural history as found in the writings of Boyle and Hooke who took inspiration from Bacon. We argue that it is best understood in terms of a typology of experiments, including luciferous and fructiferous experiments and crucial experiments, which were theorised and tried by the first generations of experimental philosophers. Many of the virtuosi in the early Royal Society and those within its ambit practised experimental natural history, and we illustrate this in the work and writings of Christopher Merrett, Thomas Henshaw, William Petty, and Robert Plot. We then discuss the eclipse of Baconian natural history in the wake of the emergence of a new mathematical approach to experimental philosophy that derived from the work of Isaac Newton.

This chapter begins with a survey of the young Newton’s early exposure to experimental philosophy and then turns to the emergence of experimental pedagogy in the last years of the seventeenth century and its rapid expansion in the early decades of the century that followed. The proliferation of courses in experimental philosophy, both public and university-based, in Oxford, Cambridge, London, and St Andrews, is testimony to its success and legitimacy. So much so, we argue, that when his commitment to universal gravity came under attack by Continental detractors, Newton openly and very strategically aligned himself with experimental philosophy, in part because of the credibility that this approach to natural philosophy already possessed. This is not to claim that every Newtonian was partial to experimental philosophy, and in this chapter we examine the views of one opponent, the Oxford natural philosopher John Keill. We document the process by which Newton publicly declared himself to be an experimental philosopher in the second edition of the Principia of 1713, and then go on to examine his role in the eclipse of Baconian natural history.

This chapter traces the emergence of experimental philosophy in England from the late 1650s in the precursor groups to the Royal Society and, in particular, in the natural philosophical method of Robert Boyle. It provides a detailed examination of the development of Boyle’s experimental philosophy and an overview of the adoption of experimental philosophy by many virtuosi in the fledgling Royal Society. From there it turns to early opposition to experimental philosophy by the likes of Meric Causabon and Margaret Cavendish, and the application of the methodology in English medicine, particularly amongst the chymical physicians. The next sections of the chapter examine the spread of experimental philosophy to the Continent and its impact on religion. The new approach to natural philosophy was said to have a positive effect on those who practise it, and its principles were soon applied in both natural religion and Christian apologetics. Finally, we turn to the questions of the shifting speculative targets of the experimental philosophers, pointing out that Descartes’ vortex theory came in for particularly harsh criticism, and the conceptual question as to who qualifies as an experimental philosopher.

According to a widespread narrative of early modern philosophy, the early modern period was characterised by the development of Descartes’, Spinoza’s, and Leibniz’s rationalism and Locke’s, Berkeley’s, and Hume’s empiricism. The early modern period came to a close once Immanuel Kant, who was neither an empiricist nor a rationalist, combined the insights of both movements in his new Critical philosophy and inaugurated the new eras of German idealism and late modern philosophy. Several scholars have criticised this narrative for overestimating the importance of epistemological issues for early modern philosophers, portraying Kant’s Critical philosophy as a superior alternative to empiricism and rationalism and forcing most early modern thinkers prior to Kant into the empiricist or rationalist camps. Kant’s three Critiques are the first published works that explicitly contrast the terms ‘empiricism’ and ‘rationalism’. This chapter sets out Kant’s contributions to the genesis of the historiographical narrative based on the dichotomy of empiricism/rationalism and argues that Kant is not directly responsible for the biases of that narrative. Kant did not regard the empiricism/rationalism distinction as purely epistemological, did not portray most of his early modern predecessors as empiricists or rationalists, and did not place himself over and above empiricism and rationalism.

This chapter documents the widespread influence of experimental philosophy in eighteenth-century Germany. We first argue that Christian Wolff, the most influential German philosopher of the period, engaged at length with the methodological views of experimental philosophers and relied extensively on experience as the foundation of his own philosophy. However, his focus on developing a comprehensively deductive philosophical system ultimately overshadowed his commitment to basing philosophy on experiments and observations. We then show how the pair of experimental and speculative philosophy became enshrined in the structure of the Berlin Academy as a result of the rebranding of its disciplinary classes in 1746. Turning to the second half of the eighteenth century, we focus on the uptake of the methodological views of experimental philosophers in the literature on empirical psychology that flourished in the period; the reflections on the relation of experimental and speculative philosophy of Johann Nikolaus Tetens, a proponent of empirical psychology who influenced Immanuel Kant; and the contrasts between experimental and speculative methods in a range of works published toward the end of the century. As Kantian and post-Kantian philosophies rose in popularity, a priori reflection gained increasing acceptance and experimental philosophy went out of fashion.

This chapter discusses the historical origins and emergence of the distinction between experimental philosophy and speculative philosophy. It opens with a summary of certain disciplinary-specific shifts in the late Renaissance that led to an increased appreciation of the value of experiment and observation. It then turns to the crucial traditional distinction between speculative and practical knowledge, which can be traced all the way back to Aristotle and was central to medieval and Renaissance understandings of the disciplines. Traditionally, natural philosophy had been classed as a speculative science, but interesting new approaches can be found in Roger Bacon, in the practice of natural magic, and in mechanics. These developments paved the way for the emergence of Francis Bacon’s division of natural philosophy as having a speculative and a practical, or operative, side. Francis Bacon’s heirs were to embrace his emphasis on the role of experiment in the operative side of natural philosophy, and by the 1660s in England a new form of operative natural philosophy emerged that its practitioners and advocates called experimental philosophy. In many contexts, it was set against the older, speculative approach to natural philosophy.