The World Turned Geometrical: An Introduction to the Philosophy of Descartes

“I beg you to send me the names of the authors who have written textbooks of philosophy, and to tell me which are the most commonly used, and whether they have any new ones since twenty years ago.” Descartes to Mersenne, 30th September 1640

This course will be an introduction to the philosophy of Descartes that situates him within his philosophical and scientific context. If you want to know what a philosopher thinks, you need to read their primary works; if you want to know, as Descartes did: what they thought they were arguing against and the ideas they took to be commonsensically true, the problems that were central, and those that were peripheral, you need to read the textbooks in use at the time.

I will attempt a double estrangement from our twenty-first century commonplaces: firstly, an explanation and description of the philosophical and scientific world view that Descartes was embroiled in – some of which he sought to overthrow and other parts, parts that we now would consider very strange, he thought so obviously right, as to not be worth debating. We can call this world view “Aristotelian” but it is the Aristotle of the textbooks used in schools and universities.

After having become convinced and committed Aristotelians, the second estrangement is that of Descartes’ work itself. Rather than structure the course around a key text, it will focus on four key ideas and themes: being, moving, thinking, and willing. These ideas do cover the classic Cartesian split between mind and body, but they help to see just why Descartes thought the world could so easily be split in this way. We will see the ways in which he helped to dismantle the world of living, organic bodies and replace it with bodies that were no more than shapes and motions. But also we will see the way in which the complex faculty psychology of the Schools was broken down into two fundamental operations: perceiving and willing.

Core Key texts for the whole course:

Primary texts:

• Descartes, René. 1984a. The Philosophical Writings of Descartes. Vol. 1. Cambridge University Press.
• Descartes, René. 1984b. The Philosophical Writings of Descartes. Translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch. Vol. 2. Cambridge University Press.
• Descartes, René. 1991. The Philosophical Writings of Descartes. Translated by John Cottingham, Robert Stoothoff, Dugald Murdoch, and Anthony Kenny. Vol. 3. Cambridge University Press. Copac.

Secondary texts:

• Ariew, Roger. 2011. Descartes among the Scholastics. History of Science and Medicine Library 20. Brill.
• Broughton, Janet, and John Peter Carriero, eds. 2008. A Companion to Descartes. Blackwell Companions to Philosophy 38. Blackwell Publishing.
• Pasnau, Robert. 2011. Metaphysical Themes, 1274-1671. Clarendon Press ; Oxford University Press.
• Schmaltz, Tad M. 2020. The Metaphysics of the Material World: Suárez, Descartes, Spinoza. Oxford University Press.

 Course Schedule

Week 1) The World: “Aristotle” (i.e. Suarez & the textbook tradition) on Being, Thinking, Moving, Willing.

This week will lay out the “Aristotelian” world view that Descartes inhabited. It will focus on four key problems that arise in Aristotle’s Metaphysics and Physics, but from the point of view of the discussions amongst Descartes’ contemporaries and teachers. These problems are: what are the most general ways of describing the world: the problem of the categories. What is the structure of the thinking subject: the problem of faculty psychology and substantial forms. What are the best ways of describing the physical world: The problem of the four causes and just what is a body? Finally, willing: how do these debates interact with Christian concerns around divine judgement and the immortality of the soul.

Key texts:

• Adriaenssen, Han Thomas. 2019. ‘Common Conceptions and the Metaphysics of Material Substance: Domingo de Soto, Kenelm Digby and Johannes de Rae’. Journal of Early Modern Studies 8 (1): 117–39.
• Des Chene, Dennis. 2008. ‘Aristotelian Natural Philosophy:  Body, Cause, Nature’. In A Companion to Descartes, edited by Janet Broughton and John Peter Carriero. Blackwell Companions to Philosophy 38. Blackwell Publishing.

Week 2) Descartes on Being: quantity and quality, extension and thought (formal, objective, degrees of reality).

This week will address a series of questions: why did Descartes think that the world could be split between thought and extension? What that split entailed and meant. Finally, what is meant by the puzzling phrase: “degrees of reality”?

Key text:

• Descartes, René. 1984. ‘Third Meditation’. In The Philosophical Writings of Descartes, translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch, vol. 2. Cambridge University Press.

Week 3) Descartes on thinking as perceiving. How can you perceive a shape without colour or a sound without pitch?

What does it mean to think? How should we understand the argument of the “cogito, sum”? Additionally, with all secondary qualities banished from the corporeal world, how does perception still work? How can bodies which only have primary qualities (size, shape, position, speed) without the secondary qualities like: colour, smell, temperature, etc. give rise, in the thinking thing, to these phenomenal sensations?

Key texts:

• Descartes, René. 1984. ‘The World or Treatise on Light’. In The Philosophical Writings of Descartes, vol. 1. Cambridge University Press.
• MacIntosh, J. J. 1983. ‘Perception and Imagination in Descartes, Boyle and Hooke’. Canadian Journal of Philosophy 13 (3): 327–52. https://doi.org/10.1080/00455091.1983.10715841.
• Waldow, Anik. 2020. ‘Descartes, Malebranche, and the Crisis of Perception, by Walter Ott’. Mind 129 (514): 673–81. https://doi.org/10.1093/mind/fzz039.

Week 4) Descartes on moving: change, physics, vortices, a world without ends/final causes.

The Ancient Greek word αἴτῐον ‘aítĭon’ meant both cause and explanation. This means that the Aristotelian model of the ‘four causes’ (material, formal, efficient, final) was simultaneously a model of the four different parts of what made a complete, or whole, explanation. With the abandonment of all forms of causation, except the efficient, how did Descartes aim to explain the physical world? Can you give a complete explanation of physical and biological systems without recourse to the formal or final causes?

Key texts:

• Descartes, René. 1984. ‘Principles of Philosophy’. In The Philosophical Writings of Descartes, vol. 1. Cambridge University Press.
• Friedman, Michael. 2008. ‘Descartes and Galileo: Copernicanism and the Metaphysical Foundations of Physics’. In A Companion to Descartes, edited by Janet Broughton and John Peter Carriero. Blackwell Companions to Philosophy 38. Blackwell Publishing.

Week 5) Descartes on thinking as willing: God, judgement, and the immortality of the soul.

It should not be overlooked that the subtitle to Descartes’ Meditations was: “in which are demonstrated the existence of God and the immortality of the soul”. Why did the existence of God need to be proved and how did Descartes go about it? Equally importantly, why, if a soul is posited, would it not automatically be immortal? What was the problem of a mortal soul, that Descartes felt he had to combat? 

Key texts:

• Adler, Jacob. 2014. ‘Mortality of the Soul from Alexander of Aphrodisias to Spinoza’. In Spinoza and Medieval Jewish Philosophy, edited by Steven Nadler. Cambridge University Press.
• Curley, Edwin M. 2001. ‘The Immortality of the Soul in Descartes and Spinoza’. Proceedings of the American Catholic Philosophical Association 75: 27–41. https://doi.org/10.5840/acpaproc2001758.