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Descartes and the Mechanical Philosophy

The powerpoint slides for this week's lecture are available here

What are the building blocks of the universe? If the world is a book, what are the letters? Aristotle had given an answer in terms of the four elements, the four qualities, and something called 'prime matter.' René Descartes believed he had a completely different answer, and many of his contemporaries agreed. Descartes was a French-born philosopher who developed what came to be known as 'the mechanical philosophy', according to which the natural world consists in nothing but matter in motion. Descartes' universe was a stripped-down version of Aristotle's: Descartes' had one element rather than four, and the only qualities he recognised were shape, size, and speed. The mechanical philosophy, so-called because it depicted the world as a machine, was extremely popular in the seventeenth century, not just among philosophers but among a wider public. The philosophy certainly had its critics, some of them vociferous, but many critics ended up modifying the philosophy rather than rejecting it altogether. Why was Descartes' machine-based vision of the universe so popular? The best way to find out is to look closely at some examples of Cartesian science.


What was the mechanical philosophy? For answers, see the Henry reading and the lecture.

How did Descartes use this philosophy to explain particular phenomena? For examples, see the reading on 'Salt'. You don't need to master the whole reading; focus on one or two properties of salt that Descartes explains, eg. the evaporation of salty water, the sharp taste of salt, etc.

In the second part of the seminar you will do some Cartesian science of your own. You will be presented with a striking natural phenomenon that you have never seen before, and asked to invent a mechanical explanation for it.

Essential reading

Descartes, René, Discourse 3 (Of Salt), in his Meteorology, (originally published, with the Discourse on Method, in 1637). Discourse 3 runs from pages 275 to 286. The first and second discourses are included in the pdf for anyone who is interested.

Henry, John. The Scientific Revolution and the Origins of Modern Science. Chapter 5 (The Mechanical Philosophy).

Further Reading

Prince Rupert drop reading:

Series of blog posts summarising seventeenth-century attempts to account for the glass drop experiment:

Academic article by the same historian:

For a typical modern-day explanation, see this blog post by a scientist, especially the bit under 'don't try this at home':

For videos of the experiment, including slow-motion videos of a bullet colliding with the drop, type 'Prince Rupert drop' into Youtube.

Descartes, René. Discourse on the Method of Rightly Conducting One’s Reason and Seeking Truth in the Sciences (originally published 1637, translation by Jonathan Bennett). See especially Part 2 (where Descartes describes his method of natural inquiry) and Part 5 (where he summarises his whole natural philosophy). The translator's note at the start of the text will help you make the most of his annotations.

Gaukroger, Stephen. "Introduction." In Descartes: The World and Other Writings -- the introduction has a good summary of the contents of Descartes' The World.

Ariew, Roger. Descartes and the First Cartesians. Oxford: Oxford University Press, 2015.

Blair, Ann. "Natural Philosophy." In CHS3.

Cottingham, John. The Cambridge Companion to Descartes. Cambridge, UK: Cambridge University Press, 1992 -- there are several relevant chapters here; note especially the article by Desmond Clarke, "Descartes' Philosophy of Science and the Scientific Revolution"

Dobre, Mihnea, and Tammy Nyden-Bullock, eds. Cartesian Empiricisms. Dordrecht: Springer, 2013.

Gaukroger, Stephen. Descartes’ System of Natural Philosophy. Cambridge: Cambridge University Press, 2002.

Descartes stick

A diagram from Descartes' The World that uses a crooked stick to illustrate how a crooked line of particles can exert a straight-ahead force.