Descartes, René (mechanism: cosmological, biological)
Descartes, René. The Philosophical Writings of Descartes. Trans. John Cottingham, Robert Soothoff, Dugald Murdoch. 2 vols. Cambridge, UK: Cambridge UP, 1985.
Gives marginal page citations to Oeuvres de Descartes, ed. Ch. Adam and P. Tannery, rev. edn. (1964-76), which we give below in square brackets. Does not contain Geometry (1637) but does have the rest of the works that laid the groundwork for a rigorously mechanistic view of the physical universe, nonhuman animals, the human body, human thought, and, ultimately—though emphatically not for RD—human beings. (In Geometry, RD presents analytic geometry, where the world can be placed on Cartesian coordinates and described algebraically. Truly Modern cities are placed on precisely those coordinates, and we who grew up in them look for 0, 0 points as the "natural" way to begin mapping the world.)
For RD on mathematical reasoning as the way to truth and for the assumption that ". . . there is only one truth concerning any matter," see Discourse on the Method, Part Two, I.120-21 [VI.19-22]. For RD's limitation of physics and possibly science in general to what can be done with the "principles . . . of geometry and pure mathematics," which can "explain all natural phenomena, and enable us to provide quite certain demonstrations regarding them" (italics removed), see Principles of Philosophy, Part Two, assertion 64: I.247 [VIIIA.78-79].
For RD's granting that, prior to admitting the human soul, he had "described this earth and indeed the whole visible universe as if it were a machine," see Principles of Philosophy, Part Four, assertion 188: I.279 [VIIIA.315-16].
For mechanistic explanations of the human body and animals, and a word or two on automata, see Treatise on Man, I.100-101 [XI.131-32]; Discourse on the Method, Part Five, I.134 [VI.46], I.139 [VI.55-56], I.139-40 [VI.56-57]; Meditations on First Philosophy, II.58-59 [VII.84-87]. See also T. Hobbes's objection to "I am a thinking thing," which Hobbes finds "Correct"—but concludes that it "seems that the correct inference is that the thinking thing is material rather than immaterial": Objections and Replies to Meditations on First Philosophy: "Third Set of Objections with the Author's Replies," Second Objection, II.122-23 [VII.172-75]; the classic insult is that with the soul RD presents a "ghost in the machine," and Hobbes does his best to remove the "ghost."