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  • Print publication year: 2015
  • Online publication date: January 2016

True and Immutable Nature



Like many philosophers, Descartes draws a distinction between the existence of a thing and its essence or nature. Even if an entity does not exist, presumably there is still a fact about what the entity would be like if it did exist. Sometimes Descartes speaks of an essence as an idea that is before a mind when it is thinking of an object (AT VIIIA 27–28, CSM I 212–13; AT IV 348–50, CSMK 279–81). Descartes also speaks of the essences as things that exist independently of our ideas of them – for example, when he discusses existing objects and the essences that constitute them (AT IV 348–50, CSMK 279–81). For Descartes, an essence or nature can exist in thought, and it can also exist in reality or in re.

Descartes introduces the notion of a true and immutable nature in the Fifth Meditation. One of the central goals of this meditation is to provide an additional argument for the existence of God, and Descartes sets up that argument by engaging a discussion of truths about triangles and other geometrical figures (see ontological argument). More specifically, he notices that there are “ideas of things which even though they may not exist anywhere outside me still cannot be called nothing” (AT VII 64, CSM II 44). The reason they cannot be called nothing is that “various truths can be demonstrated of them” – for example, that the three angles of a triangle add to two right angles, and that the longest side of a triangle subtends the triangle's greatest angle. Such truths “are not my invention” for we “clearly recognize [them] whether we want to or not” (AT VII 64, CSM II 44–45). There is something that we are picking out when we demonstrate a result about a triangle, an entity that puts constraints on what we can truly think about triangles and what we cannot. Triangular figures may not exist, but the fact that we recognize truths about them entails that triangles are “not merely nothing” but “have their own true and immutable natures” (AT VII 64–65, CSM II 44–45).

Cunning, David. 2008. “Fifth Meditation TINs Revisited: A Reply to Criticisms of the Epistemic Interpretation,” British Journal for the History of Philosophy 16: 215–28.
Cunning, David. 2003. “True and Immutable Natures and Epistemic Progress in Descartes’ Meditations,” British Journal for the History of Philosophy 11: 235–48.
Doney, Willis. 2005. “True and Immutable Natures,” British Journal for the History of Philosophy 13: 131–37.
Kenny, Anthony. 1970. “The Cartesian Circle and the Eternal Truths,” Journal of Philosophy 67: 685–700.
Kenny, Anthony. 1968. Descartes: A Study of His Philosophy. Bristol: Thoemmes Press.
Nolan, Lawrence. 2005. “The Ontological Argument as an Exercise in Cartesian Therapy,” Canadian Journal of Philosophy 35: 521–62.
Nolan, Lawrence. 1997. “The Ontological Status of Cartesian Natures,” Pacific Philosophical Quarterly 78: 169–94.
Rozemond, Marleen. 2008. “Descartes’ Ontology of the Eternal Truths,” in Contemporary Perspectives on Early Modern Philosophy: Essays in Honor of Vere Chappell, ed. Hoffman, P., Owen, D., and Yaffe, G.. Peterborough: Broadview Press, 41–63.
Schmaltz, Tad M. 2014. “The Fifth Meditation: Descartes’ Doctrine of True and Immutable Natures,” in The Cambridge Companion to Descartes’ Meditations, ed. Cunning, D.. Cambridge: Cambridge University Press, 205–22.
Schmaltz, Tad M. 1991. “Platonism and Descartes's View of Immutable Essences,” Archiv für Geschichte der Philosophie 73: 129–70.