one ever deliberates about what is past, but only about that which is future, and which may therefore be influenced, whereas what has been cannot not have been: and so Agathon is right in saying
“Of this alone is Deity bereft,
To make undone whatever hath been done.”
Thus then Truth is the work of both the Intellectual Parts of the Soul; those states therefore are the Excellences of each in which each will best attain truth.
Chapter III.
Commencing then from the point stated above we will now speak of these Excellences again. Let those faculties whereby the Soul attains truth in Affirmation or Negation, be assumed to be in number five:133 viz. Art, Knowledge, Practical Wisdom, Science, Intuition: (Supposition and Opinion I do not include, because by these one may go wrong.)
What Knowledge is, is plain from the following of considerations, if one is to speak accurately, instead of being led away by resemblances. For we all conceive that what we strictly speaking know, cannot be otherwise than it is, because as to those things which can be otherwise than they are, we are uncertain whether they are or are not, the moment they cease to be within the sphere of our actual observation.
So then, whatever comes within the range of Knowledge is by necessity, and therefore eternal, (because all things are so which exist necessarily,) and all eternal things are without beginning, and indestructible.
Again, all Knowledge is thought to be capable of being taught, and what comes within its range capable of being learned. And all teaching is based upon previous knowledge; (a statement you will find in the Analytics