Stephen Harrop

I examine the (mediated) correspondence between Spinoza and Robert Boyle concerning the latter’s account of fluidity and his experiments on reconstitution of niter in the light of the epistemology and doctrine of method contained in the Treatise on the Emendation of the Intellect. I argue that both the Treatise and the correspondence reveal that for Spinoza, the proper method of science is not experimental, and that he accepted a powerful under-determination thesis. I argue that, in contrast to modern versions, Spinoza’s form of naturalism was a highly rationalist and anti-empirical one. I conclude with a brief account of the value of experience and experimentation for Spinoza’s scientific method.

Leibniz often refers to the Principle of Sufficient Reason (PSR) as something like a first principle. In some texts, however, he attempts to give positive arguments in its favor. I examine two such arguments, and find them wanting. The first argument has two defects. First, it is question-begging; and second, when the question-begging step is excised, the principle one can in fact derive is highly counter-intuitive. The second argument is valid, but has the defect of only reaching a nearly trivial conclusion.

Priority monism is the doctrine that there is only one basic object: the entire cosmos. Priority monists often take this to be a metaphysically necessary thesis. I explore the consequences of modalizing the priority monist thesis. I argue that, modulo some assumptions, the modalized thesis entails the necessary existence of the actual cosmos. I further argue that, if the modalized thesis is true, and the actual cosmos necessarily exists, then the only possible concrete objects are the actually existing ones.

In the second chapter of her <i>Institutions de Physique</i> Emilie Du Chatelet gives two cosmological arguments for the existence of God. In this chapter I focus on the first of these arguments. I argue that, while it bears some significant similarities to arguments given by John Locke and Christian Wolff, it improves on these arguments in at least two ways. First, it avoids a potential equivocation in Locke's argument; and second, it avoids Wolff's mere stipulation that whoever claims that there cannot be an infinite regress of contingent beings does not understand what a sufficient reason is. I finally argue that her argument avoids a related objection, considered by David Hume, on which to explain a causal chain is merely to explain each link in the chain.

Emilie Du Chatelet and Christian Wolff both argue, from the principle of sufficient reason, that extended objects and composite objects simpliciter must ultimately be composed of simple beings (monads). Leonhard Euler, who makes extended use of the principle of sufficient reason in his works on mechanics and natural science, argues the contrary: Every extended object is composed of other, composite, extended objects. In this chapter I attempt to locate the differences between these figures that drive them to disparate conclusions. I argue that the difference comes, not from their different applications of the principle of sufficient reason, but from two other sources. First, they endorse different explicability principles which do not themselves follow from the principle of sufficient reasons; and second, they differ with respect to the kinds of explanations (what I call that-explanations and how-explanations) that the question of the composition of extension requires.