• Part 5 comes in three pieces. First (pp. 23-26), there is a partly autobiographical discussion which also sets out Descartes’ basic approach to physical theory. At the end, he elaborates his view of the distinction between humans and other animals. This view has a place in the Meditations but he says more about it here then he does there. Between the two is a detailed account of the heart’s motion. We will pay far less attention to this. As physiology, it is a step backward from Harvey (who Descartes mentions), and Descartes presents it less as a scientific achievement than as an example of his mechanical view of the body’s functions.

• Part 6 is also partly autobiography (and partly advertisement), but it is mainly Descartes’ presentation of his view of the place of science in society and of experiment in science. Compare what he says with your own views on these matters. Among the differences, you might find what he says about probability a little surprising. If so, while that is probably due partly to differences in your points of view, it may be due as well to changes in the concept of probability that occurred after Descartes wrote. In his era, probability was associated mainly with weighing the testimony of various authorities. (The beginnings of the association of the concept of probability with a mathematical theory of chances began with work of Pascal and Fermat shortly after Descartes’ death.)