1. See the concluding proposition (Proposition 7) of the Tractatus (Ludwig Wittgenstein, Tractatus Logico-Philosophicus, trans. D.F. Pears and B.F. McGuinness [London: Routledge, 2001], 89). In the notes that follow, I shall usually refer to ancient sources by chapter or line number only, but to modern sources by giving a full reference to a more recent edition.
2. Here I have in mind the Kierkegaardian critique of the limits of the Socratic approach. See Alastair Hannay and Gordon D. Marino, eds., The Cambridge Companion to Kierkegaard (New York: Cambridge, 1998), 104–105.
3. Here I have in mind a philosophy in which contradictions, instead of being resolved, are regarded as fruitful. For example, take the conclusion of the second half of the Parmenides: “whether one is or is not, it and the others both are and are not, and both appear and do not appear all things in all ways, both in relation to themselves and in relation to each other” (Plato, Parmenides, in Plato: Complete Works, eds. John M. Cooper and D.S. Hutchinson [Indianapolis, IN: Hackett, 1997], 397, line 166C3–5).
4. Even the illusion of truth itself will discover itself to be an illusion. See Friedrich Nietzsche, Twilight of the Idols, in The Portable Nietzsche, ed. and trans. Walter Kaufmann (New York: Viking Penguin, 1982), 486: “The True World—We Have Abolished.”
5. I take it that the “now” of Parmenides (Fragment 8, line 5) is not a passing moment, but rather the eternal present. But see the fine article by Malcolm Schofield, “Did Parmenides Discover Eternity?” Archiv für Geschichte der Philosophie 52 (1970): 113–135.