[Observation], astronomy must not be studied by, iv. [73];
nor acoustics, [74].
[Obstetric], of Sokrates, i. [367], ii. [251], iii. [112], [176].
[Odysseus], ii. [56].
[Oken], Pythagoreanism, i. [10 n.]
[Oligarchy], iv. [79];
Plato’s second state a compromise of democracy and, [333], [337].
Ὁμώνυμα, first distinguished from συνώνυμα by Aristotle, iii. [94 n.]
Ὁμωνύμως, ii. [193].
[One], in the Many, and Many in the One, aim of philosophy, i. [407];
difficulties about many and, iii. [339];
see [Idea].