I argue that Émilie Du Châtelet breaks with Christian Wolff regarding the scope and epistemological content of the principle of sufficient reason, despite his influence on her basic ontology and their agreement that the principle of sufficient reason has foundational importance. These differences have decisive consequences for the ways in which Du Châtelet and Wolff conceive of science.

For Émilie Du Châtelet, I argue, a central role of the principle of sufficient reason is to discriminate between better and worse explanations. Her principle of sufficient reason does not play this role for just any conceivable intellect: it specifically enables understanding for minds like ours. She develops this idea in terms of two criteria for the success of our explanations: “understanding how” and “understanding why.” These criteria can respectively be connected to the determinateness and contrastivity of explanations. The crucial (...) role Du Châtelet’s principle of sufficient reason plays in identifying good explanations is often overlooked in the literature, or else run together with questions about the justification and likelihood of explanations. An auxiliary goal of the article is to situate Du Châtelet’s principle of sufficient reason with respect to some of the general epistemological and metaphysical commitments of her Institutions de Physique, clarifying how it fits into the broader project of that work. (shrink)

In her Discourse on Happiness, Émilie du Châtelet argues susceptibility to illusion is one of the five ‘great machines of happiness,’ and that ‘we owe most of our pleasures to illusions’. However, many who read the Discourse find this aspect of her view puzzling and in tension with her claims that we must always seek truth and obey reason. To understand better her claims in the Discourse on Happiness, this article explores Du Châtelet's discussions of illusions in her Foundations of (...) Physics, On Liberty, and the Dissertation on the Nature and Propagation of Fire. I distinguish four types of illusions that Du Châtelet posits and clarify the ways in which these relate to her views on happiness and love in the Discourse and argue that she avoids deceptive or perpetual illusions of happiness through the use of the principle of sufficient reason. (shrink)