Primary Qualities, [32]
Protagoras, His book The Truth, [10], [11]; His maxim, [44]
Pythagoras, [87]
Relativity, Principle of, [48], [53], [62]
Republic of Plato, [67]
S. Anselm's Argument, [29], [31], [41]
Schiller, Dr. F. C. S., [44]
Self, The Idea of, [36]