amining every possible mode by which perception in the senses and impressions in the mind can be varied and inter-changed, it will be found that false judgment takes place where either the perception or the impression is imperfect and indistinct[1].
Socrates, however, is not satisfied with this conclusion, that false judgment proceeds from the conjunction of perception with thought, and shews that the mind alone by itself may err, for instance a man may think that seven and five make eleven, though he knows they make twelve; so that there must be either no false judgment at all, or it is possible for a person not to know what he knows. Theætetus is unable to choose between these alternatives. Socrates therefore proposes to abandon their present course of argument and at once to enquire what it is to know. Some people say it is to have science, Socrates prefers saying it is to possess science; for having differs from possessing in that what we have, we use, but what we possess, we use or not as we please. Suppose the soul then to be a kind of aviary containing all sorts of birds, and let the birds stand for sciences; now all the sciences that are shut up in this aviary a man may be said to possess, but when he has occasion to use any particular science, he may by mistake take one instead of another, thus when he thinks that eleven is twelve he takes the science of eleven instead of that of twelve, and so judges falsely; but when he takes that which he endeavours to take, he judges truly. Still another even worse inconvenience appears to Socrates to follow from this; for it is absurd to suppose that a person who has the science of any thing should at the same time be ignorant of that thing; and if that can be, nothing hinders but that ignorance when present should make us know something. So that after all they have only come round again to the point from whence they started and have still to enquire what science is. Theætetus persists in answering that it is true judgment. But Socrates shews that this cannot be the case; for that judges, who listen to the arguments of lawyers, form true judgments without science,
- ↑ § 108–125.
