I. Wherein is the Criterion for the Apprehension of the Soul. All things that exist are either known by sense 442 or apprehended by thought. 443 And what falls under sense has its adequate demonstration in sense itself; for at once, with the application, it creates in us the impression 444 of what underlies it. But what is apprehended by thought is known not by itself, but by its operations. 445 The soul, consequently, being unknown by itself, shall be known property by its effects. 442     αἰσθήσει . 443     νοήσει . 444     φαντασίαν . 445     ἐνεργειῶν .