 Although Augustine shaped the theology of Jansenism, René Descartes’ influence predominates in the philosophical aspects of the Logic. Arnauld’s insightful and respectful set of “Objections” to Descartes’ Meditations along with Descartes’ “Replies” were first published in 1641 (see Descartes 1984 for English translation, abbreviated CSM). This exchange confirmed Arnauld in his belief that Descartes’ system of philosophy was very well suited to furthering his own version of the Port-Royal theological program. He was impressed by Descartes’ frequent insistence that natural science, metaphysical speculation, and even mathematics and logic were to be subordinated to ethical and religious ends (Lachterman 1989, Jones 2006). Especially important was Descartes’ project of demonstrating that the foundations of natural science are compatible with, and in fact depend on God. The dualism of mental and corporeal created substances made it possible to conceive the natural world mechanically without recourse to any of the additional quasi-spiritual entities posited by Aristotelians. Geometrically construed matter requires only God’s creative activity to be the subject matter of Cartesian physics. The Logic’s introductory “First Discourse” announces the intention to choose examples throughout the book that promote both correct religious morality and the best (i.e., Cartesian) science. Examples of how reason favors Cartesian science over its competitors are accordingly sprinkled throughout the Logic.