"Now this is by no means possible, for as soon as we turn into ourselves to make the attempt, and seek for once to know ourselves fully by means of introspective reflection, we are lost in a bottomless void; we find ourselves like the hollow glass globe, from out of which a voice speaks whose cause is not to be found in it, and whereas we desired to comprehend ourselves, we find, with a shudder, nothing but a vanishing spectre."
— Schopenhauer, Arthur (1788-1860)
Adorno cites, Arthur Schopenhauer, Die Welt als Wille und Vorstellung (Leipzig: 1877), p. 327n. Cf. 1879 edition: Die Welt als Wille und Vorstellung, ed. Julius Frauenstädt, 2 vols. (Leipzig: Brockhaus, 1879), I, 327n. <Link to Hathi Trust>
English text from Project Gutenberg: Arthur Schopenhauer, The World as Will and Idea trans. R. B. Haldane and J. Kemp, 7th ed. (London: Kegan Paul, Trench, Trübner & Co., 1909), vol. I. <Link to Vol. 1 of 3>