Rationalism

Picture a universe made up of an infinity of points of view, each of them a minuscule soul that, without ever looking out of a window, mirrors the entire cosmos within itself — and which is nonetheless in perfect agreement with all the others, as though every clock in a vast hall had been set once and for all to strike the same hour for eternity. This is the world of Gottfried Wilhelm Leibniz (1646–1716): the last great universal scholar of the modern age — mathematician, logician, jurist, diplomat, historian and theologian — who attempted the most ambitious of syntheses, reconciling the mechanical science of his time with a metaphysics of substances and with Christian theology. His philosophy is at once one of the most coherent systems ever built and one of the bridges that connect Aristotle to the mathematical logic of the twentieth century. ...

There is a philosopher who, writing in Latin in a small house in The Hague in the seventeenth century, formulated one of the most radical worldviews Western philosophy has ever produced — and did so in the unlikely form of a treatise of geometry. That philosopher is Baruch (Bento) Spinoza (1632–1677), and the treatise is the Ethics demonstrated in geometrical order, published posthumously in the year of his death. In a little over two hundred pages, organized into definitions, axioms, propositions, and demonstrations, Spinoza proposes simultaneously a metaphysics of the absolute, a theory of human affects, a psychology of knowledge, and an ethics of freedom. His influence runs across three centuries — Lessing, Goethe, Hegel, Marx, Nietzsche, Deleuze, Antonio Damasio — and his name still functions, in the history of philosophy, as a cipher for an intellectual decision: thinking God, nature, and the human being as expressions of a single reality. ...

There are few moments in the history of philosophy that can rival, in sheer radicality and consequence, the one in which René Descartes, secluded in his Dutch stove-heated room, discovered that the very act of doubting contains within itself an unshakeable certainty: whoever doubts, thinks — and whoever thinks, exists. The cogito — formulated in slightly different ways across three major works — became not merely the starting point of Cartesian philosophy but the founding act of all modern philosophy. Through it, human subjectivity installed itself at the centre of philosophical inquiry and has remained there, in various guises, for four centuries. ...

This is the second of five articles on Joseph Maréchal’s Le point de départ de la métaphysique (The Starting Point of Metaphysics). In the first article, we followed Maréchal’s reading of the classical tradition from the pre-Socratics through Thomas Aquinas, showing how ancient and medieval thought largely assumed a direct cognitive contact with being without needing to systematically justify that assumption. In this second article, we turn to Cahier II, in which Maréchal examines the great modern debate between rationalism and empiricism — and shows how both traditions, despite opposing each other on almost every point, ultimately leave the problem of objectivity unresolved and prepare the ground for Kant’s revolutionary critique. ...

Baruch Spinoza (Benedict of Spinoza) Born in Amsterdam in 1632, into a family of Sephardic Jews of Portuguese origin who had fled the Inquisition, Baruch Spinoza received a rabbinic education, but his ideas soon put him on a collision course with the community: in 1656 he was subjected to a herem (excommunication) of rare severity. He declined chairs and honors to preserve his independence of thought and supported himself humbly by grinding optical lenses. He died young, in 1677, and his principal works — among them the Ethics — were published only after his death. He is regarded as the most radical of the seventeenth-century rationalists. ...

Gottfried Wilhelm Leibniz Born in Leipzig in 1646, Gottfried Wilhelm Leibniz was the last great universal sage: at once philosopher, mathematician, logician, physicist, jurist, historian, and diplomat. He invented — independently of Newton — the infinitesimal calculus, whose notation we still use, conceived the binary arithmetic that underlies computing, and designed calculating machines. He spent much of his life in the service of the House of Hanover and died in 1716, leaving a body of work scattered across thousands of letters and few published books. Philosophically, he sought the great reconciliation of modern science, the metaphysical tradition, and faith. ...

René Descartes Often called the “father of modern philosophy,” René Descartes was born in 1596 in La Haye, in the French region of Touraine, and was educated at the rigorous Jesuit college of La Flèche. Dissatisfied with bookish learning, he enlisted as a volunteer in the armies of the Thirty Years’ War; it was during this period, by his own account, that in 1619 he glimpsed a universal method capable of giving philosophy the same certainty as mathematics. He spent most of his productive life in the Dutch Republic and died in 1650 in Stockholm, where he had been invited to tutor Queen Christina of Sweden. He was also a great mathematician: analytic geometry and the coordinate system that bears his name are his creations. ...