Thestorides! of all the skills unknown
To errant mortals, there remains not one
Of more inscrutable affair to find
Than is the true state of a human mind.
[1] Homer intimated, in this his answer to Thestorides, a will to have
him learn the knowledge of himself, before he inquired so curiously
the causes of other things. And from hence had the great peripatetic,
Themistius, his most grave epiphoneme, _Anima quæ seipsam ignorat,
quid sciret ipsa de aliis?_ And, therefore, according to Aristotle,
advises all philosophical students to begin with that study.