Cartesian Skepticism, Kantian Skepticism, and the Dreaming Hypothesis


  • Antonio Ianni Segatto São Paulo State University



Skepticism, Dreaming, Wittgenstein, Nonsense


Based on the distinction drawn by James Conant between Cartesian skepticism and Kantian skepticism, I intend to show that Wittgenstein’s remarks on dreaming should not be understood as a direct attack on the former, as commonly held, but as an indirect attack on it, for Wittgenstein approaches Descartes’ dreaming hypothesis by changing the very problematic at stake. Wittgenstein’s attack on skepticism takes one step back from a question about how to distinguish between dreaming that one is experiencing something and actually experiencing it, for this attack focuses on the linguistic conditions of the possibility of something that the Cartesian problematic takes for granted, that is, the very possibility of saying “I am dreaming.” I also intend to show that Wittgenstein’s remarks on dreaming should be read in light of his claim that skepticism is nonsensical put forward in the Tractatus logico-philosophicus as well in his last writings. More specifically, I intend to show that the words “I am dreaming” are nonsensical in the same sense as the alleged proposition “There are physical objects” and the expression of doubt about the existence of physical objects or the external world.


Coliva, A. 2010. Moore and Wittgenstein: Scepticism, Certainty and Common Sense. Basingstoke: Palgrave.

Conant, J. 1998. Wittgenstein on Meaning and Use. Philosophical Investigations 21: 222-250.

Conant, J. 2000. Elucidation and Nonsense in Frege and Early Wittgenstein. In: A. Crary & R. Read (eds.), The New Wittgenstein, p.174-217. London: Routledge.

Conant, J. 2001. A Prolegomenon to the Reading of Later Wittgenstein. In: L. Nagl & C. Mouffe (eds.), The Legacy of Wittgenstein: Pragmatism or Deconstruction, p.93-130. Frankfurt am Main: Peter Lang.

Conant, J. 2004. Why worry about the Tractatus?. In: B. Stocker (ed.), Post-analytic Tractatus, p.167-192. Aldeshot: Ashgate.

Conant, J. 2012. Two varieties of skepticism. In: G. Abel & J. Conant (eds.), Rethinking epistemology, vol. 2, p.1-74. Berlin: De Gruyter.

Conant, J. 2020. Reply to Gustafsson: Wittgenstein on the Relation of Sign to Symbol. In: S. Miguens (ed.), The Logical Alien: Conant and his Critics, p.863-947. Cambridge, MA: Harvard University Press.

Descartes, R. 1984. Meditations on First Philosophy. In: The Philosophical Writings of Descartes, vol. II. Cambridge: Cambridge University Press.

Diamond, C. 1997. Realism and Resolution: Reply to Warren Goldfarb and Sabina Lovibond. Journal Philosophical Research XXII: 75-86.

Diamond, C. 2014. The Hardness of the Soft: Wittgenstein’s Early Thought About Skepticism. In: J. Conant & A. Kern (eds.), Varieties of Skepticism: Essays after Kant, Wittgenstein, and Cavell, p.145-182. Berlin: De Gruyter.

Diamond, C. 2019. Reading Wittgenstein with Anscombe, Going on to Ethics. Cambridge, MA: Harvard University Press.

Hamawaki, A. 2020. Cartesian Skepticism, Kantian Skepticism, and Two Conceptions of Self-Consciousness. In: S. Miguens (ed.), The Logical Alien: Conant and his Critics, p.145-169. Cambridge, MA: Harvard University Press.

Kant, I. 1998. Critique of Pure Reason. Cambridge: Cambridge University Press.

Malcolm, N. 1956. Dreaming and Skepticism. Philosophical Review 65: 14-37.

Malcolm, N. 1959. Dreaming. London: Routledge & Kegan Paul.

Moyal-Sharrock, D. 2004. Understanding Wittgenstein’s On Certainty. Basingstoke: Palgrave McMillan.

Moyal-Sharrock, D. 2007. The Good Sense of Nonsense: A Reading of Wittgenstein’s Tractatus as Nonself-Repudiating. Philosophy 82: 147-77.

Mulhall, S. 2007. Wittgenstein’s Private Language: Grammar, Nonsense, and Imagination in Philosophical investigations, §§243–315. Oxford: Clarendon Press.

Proessel, D. 2005. Wittgenstein on Skepticism and Nonsense. Philosophical Investigations 28: 324-345.

Ramsey, F. 1990. Philosophical Papers. Cambridge: Cambridge University Press.

Richter, D. 2001. Wittgensteinian foundationalism. Erkenntnis 55: 349-358.

Richter, D. 2014. Historical Dictionary of Wittgenstein’s Philosophy. Second Edition. Lanham: Rowman & Littlefield.

Russell, B. 1952. Our Knowledge of the External World. London: George Allen and Unwin.

Stroll, A. 2005. Review of Wittgenstein and Scepticism. Mind 114: 757-760.

Stroll, A. 2009. Wittgenstein and the Dream Hypothesis. Philosophia 37: 681-690.

Wittgenstein, L. 1972. On Certainty [OC]. New York: Harper Torchbooks.

Wittgenstein, L.1974. Tractatus Logico-Philosophicus [TLP]. London: Routledge.

Wittgenstein, L. 1984. Notebooks 1914-1916 [NB]. Chicago: The University of Chicago Press.






Special Issue: The Logical Alien