[1] It is significant that the subject of the first treatise of Plotinos, after the departure of Porphyry, should treat of happiness as the object of life. These may have been the arguments he advanced to persuade Porphyry to abstain from suicide (to which he refers in sections 8, 16), and, rather, to take a trip to Sicily, the land of natural beauty. He also speaks of losing friends, in section 8. The next book, on Providence, may also have been inspired by reflections on this untoward and unexpected circumstance. We see also a change from abstract speculation to his more youthful fancy and comparative learning and culture.
[2] Diog. Laert. x.; Cicero, de Fin. i. 14, 46.
[3] Cicero, de Fin. 11, 26.
[4] See Arist. Nic. Eth. vii. 13; Sextus Empiricus, Hypotyp. Pyrrhon, iii. 180; Stob. Ecl. ii. 7.
[5] Arist. Nic. Eth. i. 10, 14.
[6] Stob. Floril. i. 76.
[7] See vi. 8.
[8] In Plutarch, of Wickedness, and in Seneca, de Tranquil, Animi, 14.
[9] De Providentia, 3.
[10] De Provid. 5.