His Life, Character, and Philosophy
René Descartes (1596–1650) is often called the father of modern philosophy. The title owes less to any single doctrine than to the ambition of his project. As the old Aristotelian worldview collapsed under the weight of the Scientific Revolution, Descartes set out to rebuild human knowledge from the ground up, in a way that could accommodate God, the soul, and human freedom.
A World Crying Out For a Philosopher
The demise of the Aristotelian system, brought about by the Copernican and Scientific Revolutions, left a void that needed filling—ideally by some all-encompassing metaphysical system on the scale of the old, Aristotelian one. If the Earth no longer stood at the centre of the cosmos, was man not the glory of creation, as affirmed in the Bible (1 Corinthians 11:7)? In this new mechanistic, atomistic world of matter in motion, where might God and the immaterial soul fit in? Where freedom and justice? And where, even, heaven and hell?
As recently as 1588, Galileo, qua mathematician, had been invited to address the Florentine Academy on the location, size, and arrangement of hell as described in Dante’s Inferno—underscoring the scale of the mind shift required. Even that paragon of the Scientific Revolution, Newton, albeit in secret, dedicated the larger part of his life to alchemy and the search for the fabled philosopher’s stone.
The three seventeenth-century philosophers who rose to the challenge of formulating a comprehensive metaphysics are René Descartes (1596–1650), Baruch Spinoza (1632–1677), and Gottfried Wilhelm Leibniz (1646–1716), who sometimes inserted, with little to no justification, the nobiliary particle von in front of his cognomen.
Three Visions in a Stove-Heated Room
Descartes categorically rejected the substantial forms and primary matter of the mediaeval, Aristotelian schoolmen. In a letter to his friend Marin Mersenne dated 28 January 1641, he writes that his Meditations on First Philosophy ‘contain all the foundations of my physics. But please do not tell people, for that might make it harder for the supporters of Aristotle to approve them. I hope that readers will gradually get used to my principles, and recognise their truth, before they notice that they destroy the principles of Aristotle.’
Two decades earlier, Descartes had been serving in the army of Duke Maximilian of Bavaria. On 10–11 November 1619, while stationed near Ulm or else Neuberg an der Donau, he found refuge in a room with an ‘oven’ (probably a cockle stove) to escape from the cold and reflect on his thoughts. That night, he had three dreams which determined the course of his life. To repay these visions, he vowed to make a pilgrimage to the shrine of Our Lady of Loretto in the Italian region of Marche—and, in 1623, fulfilled his vow.
What Descartes had seen or grasped on that eve of St Martin’s Day 1619 is the unity of the sciences under mathematics: if a concrete problem could be abstracted into mathematical form, it would become clearer and more amenable to solving. Thus, in the course of his life, he contributed several mathematical innovations. In his La Géométrie (1637), he introduced the modern exponential notation which is taught in every contemporary school. He established the convention of using the letters x, y, z to represent unknown variables in equations, and a, b, c to represent known variables. If that were not impressive enough, he bridged algebra and geometry by transforming numerical relationships into geometrical shapes, plotting these lines and curves on a coordinate plane, and showing how they could be represented in the form of algebraic equations—a field now known as analytic, coordinate, or Cartesian geometry.
Descartes sought to carry the certainty of mathematics into philosophy itself. The culmination of that lifelong project was the Meditations on First Philosophy, which laid the foundations of his new metaphysical system while quietly dismantling that of Aristotle.
The Method of Doubt (Dubitatio methodica)
The closed-in stove-heated room later came to symbolise Descartes’ famous method of doubt, by which he systematically dismantled the edifice of his beliefs to rebuild on a more secure foundation of indubitable truths, to be arrived at through a predetermined set of logical rules.
In this climate of radical doubt, he could doubt the existence of the outside world, even the existence of his own body—but not that he was the one doing the doubting. This insight is encapsulated in his famous dictum, Cogito, ergo sum (‘I think, therefore I am’). The very act of doubting presupposed a thinking self to do the doubting.
Although Descartes knew that he was thinking, and so that he was, he could not be sure that his thinking bore any relation to the outside world. So he introduced an a priori proof (a proof derived from thought alone) for the existence of God, and argued that such a benevolent being would not deceive his favoured creation, man—so long as man had employed his (Descartes’s) method of doubt and taken every precaution to have ‘clear and distinct’ ideas and not to be deceived.
Dualism and the Piece of Wax Analogy
The Cogito also transformed Descartes’ understanding of reality. The indubitability of the thinking self led him to conclude that mind and body must be fundamentally different kinds of substance. The defining attribute of the mind (or soul, or res cogitans) is thought, while that of the body (or res extensa) is extension. It is by the knowable mind, rather than the deceptive senses, that the physical can be apprehended.
Descartes illustrated this point with one of the most famous passages in the Meditations: the wax analogy. When a piece of wax is heated, all its sensory properties change. Only the mind grasps its underlying essence, which consists in extension (as well as flexibility and movability in space), and recognises it as the same piece of wax. The physical, being extended, is divisible; but mind is indivisible, and therefore not physical. Since it is not physical, mind is beyond the laws of physics, and free and immortal.
[T]here is a great difference between the mind and the body, inasmuch as the body is by its very nature always divisible, while the mind is utterly indivisible. For when I consider the mind, or myself in so far as I am merely a thinking thing, I am unable to distinguish any parts within myself; I understand myself to be something quite single and complete… By contrast, there is no corporeal or extended thing that I can think of which in my thought I cannot easily divide into parts; and this very fact makes me understand that it is divisible. This one argument would be enough to show me that the mind is completely different from the body.
The Soul of Animals
Descartes’s mind-body dualism is commonly taken as the starting point of modern philosophy. His method is indeed revolutionary, but the substance of his philosophy is in fact an attempt to shelter God, man, and his immortal soul from the new mechanism. Thanks to Descartes, those who embraced the Copernican revolution could remain good Christians, or claim as much.
But in solving one problem, Descartes created several others, most notably the place of animals and the mind-body problem.
Under the Aristotelian system, all living things had a vegetative (or nutritive) soul; animals, in addition, had a sensitive soul; and humans, on top of that, had a rational soul.
For fear of granting them immortality and a place in heaven, Descartes denied souls to the animals. Animals, he claimed, are mere automata, whose functions ‘follow from the mere arrangement of the machine’s organs every bit as naturally as the movements of a clock or other automaton follow from the arrangement of its counterweights and wheels’.
For Descartes, it is not merely that animals do not reason, but also, contra common sense, that they do not feel, perceive, or sense. Clearly, he did not have a cat. According to lore, he once threw a cat out of a window in an attempt to demonstrate that the poor thing lacked consciousness.
The Mind-Body Problem
If mind and body truly are incommensurate, how is it possible for them to interact? How might my mind move me to write these words without violating, or else submitting to, the laws of physics? Conversely, how might my eyes and ears relay sense experience to my mind?
Descartes responded to this so-called mind-body problem in two ways. At times, he said, literally, ‘Only God knows.’ At other times, he suggested that mind and body interact at the pineal gland, on the grounds that this structure is mobile and central in the brain. But this only puts the problem at one remove, for the question then becomes, how is it possible for the mind to interact with the pineal gland?
The Philosopher’s Daughter
Although France’s most famous philosopher, Descartes spent the greater part of his adult life in the relative safety of the Dutch Republic. There, he met a servant called Helena who became the mother of his illegitimate daughter Francine (b. 1635), whom he passed off as his niece. When Francine died, aged five, of scarlet fever, he called it the greatest sorrow of his life, even stating that it was not unmanly to cry. Later, a legend arose that he—the philosopher who had compared living bodies to machines—constructed an automaton in her likeness.
The Tree of Life
The name René derives from the Latin Renatus, ‘born again’—fitting for the man who sought to rebuild philosophy from first principles. But although remembered as a philosopher, Descartes looked upon himself first and foremost as a natural philosopher (scientist) and physicist.
In the preface to his Principles of Philosophy (1644), he compared philosophy to a tree, with metaphysics as its roots, physics as its trunk, and the other sciences as its branches—and it is, of course, the branches that bear the fruit.
The ‘other sciences’ could be reduced to three principal ones, medicine, mechanics, and morals—which is why, in 1649, he published a book on the emotions, The Passions of the Soul. He sent a copy to his penfriend Queen Christina of Sweden, who was so impressed that she invited him to join her court.
In October 1649, he left Holland for Sweden. But the northern winter did not agree with him, and the frenetic Christina insisted on taking her lessons at five in the morning. He did not live to see the spring.
Continue Exploring
If you enjoyed this article, you might also enjoy The German Greeks, which traces the development of modern philosophy from Descartes to Nietzsche, via Leibniz, Kant, Hegel, and Schopenhauer.
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