¹ Harry Frankfurt, “Memory and the Cartesian Circle,” The Philosophical Review, October, 1962. Subsequent references to this article will be abbreviated, MC.

² MC, p. 504.

³ MC, p. 504. I shall term this “the traditional Circle Argument.”

⁴ See MC, pp. 504–505.

⁵ Descartes, Meditations on First Philosophy, trans. Haldane and Ross, The Philosophical Works of Descartes, Volume One [Dover Publications, 1955], p. 142. Subsequent references to this edition will be abbreviated as HR.

⁶ HR., p. 178.

⁷ HR., p. 180.

⁸ Descartes never explicitly argues that according to his principles an Evil Demon [or perfect devil] cannot exist in the world; nor is it difficult to imagine why, in view of the theological doctrines current in his day, he would decline to make this consequence of his principles explicit. That it is a consequence is, however, evident.

⁹ HR., p. 158.

¹⁰ See HR. p. 159: “And, certainly, since I have no reason to believe that there is a God who is a deceiver, and as I have not yet satisfied myself that there is a God at all, the reason for doubt which depends on this opinion alone is very slight, and so to speak metaphysical. But in order to be able altogether to remove it, I must inquire whether there is a God as soon as the occasion presents itself…”

¹¹ See MC, p. 504: “Indeed, he [Descartes] understood reason to be nothing but a faculty for the clear and distinct perception of ideas.” And MC, p. 505: “When a proposition is being intuited—that is, being perceived clearly and distinctly—its truth cannot be doubted.”

¹² See Descartes, The Philosophical Works of Descartes, trans. Haldane and Ross, Volume II [referred to henceforth as HR -2], “Reply to Objections II,” p. 41: “But … since … we have, as well, a real faculty of recognizing truth … unless this faculty tended towards truth, at least when properly employed [i.e., when we give assent to none but clear and distinct perceptions, for no other correct use of this faculty can be imagined] God … must justly be held to be a deceiver.” This faculty of truth is, of course, the natural light or light of nature [see HR, p. 160].

¹³ See HR., pp. 155–156, and HR-2., p. 38.

¹⁴ See HR., p. 159–160.

¹⁵ Descartes, A Discourse on Method, etc. trans. Veitch, Everyman’s Library, 1949, p. 99. In this very crucial place the usually dependable Haldane and Ross translation fails to do justice to Descartes’ text. Instead of rendering the above passage as a justification of reason, or natural light, it renders it as a mere conjunction: HR, p. 160, “I cannot doubt that which the natural light causes me to believe to be true, as, for example, it has shown me that I am from the fact that I doubt, or other facts of the same kind. And [italics mine] I possess no other faculty whereby to distinguish truth from falsehood …” But assuredly “quia” is to be translated by “since” or “inasmuch as” and not “and” in “quaecumque … similia, nullo modo dubia esse possunt, quia [italics mine] nulla alia facultas esse potest…” [Descartes, Œuvres de Descartes, Vol. VII, “Meditationes de Prima Philosophia,” Adam et Tannery, Paris, 1904, p. 38].

¹⁶ See HR., p. 184.

¹⁷ This would be implied, though not stated explicitly, in HR., p. 183.

¹⁸ See the end of the Fifth Meditation.

¹⁹ It needs to be, because otherwise we shall not possess the premise that we are not perfect beings, from which we may argue that God is a Being existing external to us.

²⁰ See HR., p. 152.

²¹ HR., p. 221.

²² HR., p. 158.

²³ HR., p. 159.

²⁴ See HR., p. 162 [Meditation Three ]; also, HR., p. 226 [Principles , part one, principle 18].

²⁵ See HR., p . 162 [Meditation Three ]; also, HR., p . 239 [Principles , part one, principle 49].

²⁶ I repeat: granting Descartes' conception of the nature of ideas.