It may be said summarily that Kant holds the antithesis between thought and "the given" to be unresolved and within the limits of theory of knowledge irreducible. The dove of thought falls lifeless if the resistant atmosphere of "the given" be withdrawn (_Critique of Pure Reason_, ed. 2 Introd. Kant's _Werke_, ed. of the Prussian Academy, vol. iii. p. 32, ll. 10 sqq.). Nevertheless the thing-in-itself is a problematic conception and of a limiting or negative use merely. He "had woven," according to an often quoted phrase of Goethe, "a certain sly element of irony into his method; ... he pointed as it were with a side gesture beyond the limits which he himself had drawn." Thus (_loc. cit._ p. 46, ll. 8, 9) he declares that "there are two lineages united in human knowledge, which perhaps spring from a common stock, though to us unknown--namely sense and understanding." Some indication of the way in which he would hypothetically and speculatively mitigate the antithesis is perhaps afforded by the reflection that the distinction of the mental and what appears as material is an external distinction in which the one appears outside to the other. "Yet what as thing-in-itself lies back of the phenomenon may perhaps not be so wholly disparate after all" (ib. p. 278, ll. 26 sqq.). [132] _Critique of Judgment_, Introd. § 2 (_Werke_, v., 276 ll. 9 sqq.); cf. Bernard's "Prolegomena" to his translation of this, (pp. xxxviii. sqq.). [133] _Die Logik, insbesondere die Analytik_ (Schleswig, 1825). August Detlev Christian Twesten (1789-1876), a Protestant theologian, succeeded Schleiermacher as professor in Berlin in 1835. [134] See _Sir William Hamilton: The Philosophy of Perception_, by J. Hutchison Stirling. [135] _Hauptpunkte der Logik_, 1808 (_Werke_, ed. Hartenstein, i. 465 sqq.), and specially _Lehrbuch der Einleitung in die Philosophie_ (1813), and subsequently §§ 34 sqq. (_Werke_, i. 77 sqq.). [136] See Ueberweg, _System of Logic and History of Logical Doctrines_, § 34. [137] _Drei Bücher der Logik_, 1874 (E.T., 1884). The Book on Pure Logic follows in essentials the line of thought of an earlier work (1843). [138] _Logic_, Eng. trans. 35 _ad. fin._ [139] _Logic_, Introd. § ix. [140] For whom see Höffding, _History of Modern Philosophy_, Eng. trans., vol. ii. pp. 122 sqq.; invaluable for the logical methods of modern philosophers. [141] _Wissenschaft der Logik_ (1812-1816), in course of revision at Hegel's death in 1831 (_Werke_, vols. iii.-v.), and _Encyklopädie der philosophischen Wissenschaften_, i.; _Die Logik_ (1817; 3rd ed., 1830); _Werke_, vol. vi., Eng. trans., Wallace (2nd ed., 1892). [142] _The Principles of Logic_ (1883). [143] _Logic, or The Morphology of Thought_ (2 vols., 1888). [144] _Logic_, Pref. pp. 6 seq. [145] _Id._ vol. ii. p. 4.