Early Modern Philosophy: Descartes and the Rationalists

Explore the intellectual climate in the 16th and 17th centuries, when early modern philosophy took off. What makes this philosophical movement modern? And what connects it to ancient and medieval philosophy? Professor Reid previews the thinkers covered in the course, and examines their connection to the ongoing Scientific Revolution and the concurrent Reformation that was dividing Christians.

A pioneer of early modern philosophy, René Descartes set the goal of building a foundation for knowledge that is absolutely certain. Trace the chain of reasoning in his Meditations on First Philosophy that led him to the self-evident truth of his own thinking existence. Look at other conclusions reached by Descartes in this remarkably subtle work.

Why was Descartes so obsessed with certainty? Delve into The Discourse on the Method, which includes an intellectual autobiography. A key step was the time he spent alone in a stove-heated room, when he concluded that a single individual using reason can get closer to the truth than the aggregate of learning contained in all books. Follow the revolutionary deductions he reached with this method.

In his Discourse, Descartes outlines a provisional moral code, but the full development of his ethical system emerges through his correspondence with Princess Elisabeth of Bohemia. A gifted philosopher, she posed challenging questions that prompted him to rigorously refine his ideas. Their colloquy explored happiness, virtue, emotions, and the passions, with a strong emphasis on practical ethics.

Descartes’s works prompted Lady Anne Conway, a reclusive English noblewoman and philosopher, to set down her ideas, which bridged metaphysics, ethics, and theology in sharp contrast to Descartes’s system. Drawing on her posthumously published treatise, Dr. Reid summarizes her influential critique of Cartesian dualism and her vitalist conception of all reality, which incorporates reincarnation.

While Descartes argued that mind and body are two distinct substances, Baruch Spinoza, proposed that there is only one substance, which he identified as God or Nature. Everything else, including mind and body, are modes or expressions of this one substance. Spinoza’s God is not a personal deity but an infinite, impersonal substance that encompasses all of reality.

Continue your study of Spinoza’s Ethics by focusing on his philosophy of mind, notably his theory of emotions. Spinoza held that despite their nature, emotions are far from random or irrational. Instead, they are part of the natural order, arising from encounters with external objects or events that affect the body, which in turn affects the mind. This was a highly innovative view at the time.

Spinoza’s theory of emotions leads to his account of bondage and freedom. Bondage relates to actions over which we have no control, while freedom is detachment from those emotions that hold us captive. These represent two opposing ways of living—one that results in frustration and suffering, and another that brings fulfillment and peace. The latter is the fundamental goal of his Ethics.

After reading Descartes, priest and philosopher Nicolas Malebranche broke with the medieval Scholastic view, which was inspired by Aristotle, and developed his own doctrine of occasionalism. This integrated Cartesian metaphysics with a vision of divine intervention. Although rooted in a theistic framework, Malebranche’s ideas influenced later, more secular thinkers such as Hume and Kant.

A co-inventor of calculus with Isaac Newton, Gottfried Wilhelm Leibniz is best known as a philosopher who built a unified explanation of reality. He called his explanatory agents monads—indivisible, non-physical entities that account for being, perception, consciousness, and other natural phenomena, and play a key role in Leibniz’s understanding of truth. Explore this powerful and subtle system.

In his satire Candide, Voltaire makes fun of Leibniz’s idea that God created “the best of all possible worlds.” What led Leibniz to this conclusion, and how does he account for the obvious shortcomings of the universe, notably evil? Examine his distinction between metaphysical, physical, and moral forms of evil. And consider his views on freedom, moral choice, and the aspiration to perfection.

In this last lecture, Professor Reid asks how the thinkers presented in the course shed light on today’s debates. Although early modern philosophers often disagree, they are committed to reason as the only hope for a more truthful way of inhabiting the world. Being philosophers, they accept that on matters of fundamental philosophical importance, reasonable people should be free to disagree.