§2.8.1Παρὰ μὲν τὸ μὴ ἐφιστάνειν, τί ἐν τῇ ἄλλου ψυχῇ γίνεται, οὐ ῥᾳδίως τις ὤφθη κακοδαιμονῶν· τοὺς δὲ τοῖς τῆς ἰδίας ψυχῆς κινήμασι μὴ παρακολουθοῦντας ἀνάγκη κακοδαιμονεῖν.
On account of not observing what is passing in another's soul, a man is rarely seen to be unhappy; but those who do not attend to the movements of their own souls must of necessity be unhappy.