[189:8] What is called "the algebra of logic" seeks to obtain an unequivocal symbolic expression for these truths.

[192:9] Plato: Protagoras, 351. Translation by Jowett.

[194:10] Plato: Apology, 41. Translation by Jowett.

[195:11] Quoted by Paulsen in his System of Ethics. Translation by Thilly, p. 69.

[198:12] Cf. § [160].

[198:13] Cf. § [177].

[199:14] Concerning the duty of philosophy to religion in these matters, cf. Descartes: Meditations, Dedication. Translation by Veitch, p. 81.

[201:15] The school-philosophy that flourished from the eleventh to the fifteenth century, under the authority of the church.

[209:16] Especially in the Phædo.

[211:17] Schopenhauer is a notable exception. Cf. §§ [135], [138].