_M._ Because the name madness[35] implies a sickness of the mind and
disease; that is to say, an unsoundness and an unhealthiness of mind,
which they call madness. But the philosophers call all perturbations of
the soul diseases, and their opinion is that no fool is ever free from
these; but all that are diseased are unsound; and the minds of all
fools are diseased; therefore all fools are mad. For they held that
soundness of the mind depends on a certain tranquillity and steadiness;
and a mind which was destitute of these qualities they called insane,
because soundness was inconsistent with a perturbed mind just as much
as with a disordered body.

V. Nor were they less ingenious in calling the state of the soul devoid
of the light of the mind, "a being out of one's mind," "a being beside
one's self." From whence we may understand that they who gave these
names to things were of the same opinion with Socrates, that all silly
people were unsound, which the Stoics have carefully preserved as being
derived from him; for whatever mind is distempered (and, as I just now
said, the philosophers call all perturbed motions of the mind
distempers) is no more sound than a body is when in a fit of sickness.
Hence it is that wisdom is the soundness of the mind, folly a sort of
unsoundness, which is insanity, or a being out of one's mind: and these
are much better expressed by the Latin words than the Greek, which you
will find the case also in many other topics. But we will discuss that
point elsewhere: let us now attend to our present subject. The very
meaning of the word describes the whole thing about which we are
inquiring, both as to its substance and character. For we must
necessarily understand by "sound" those whose minds are under no
perturbation from any motion as if it were a disease. They who are
differently affected we must necessarily call "unsound." So that
nothing is better than what is usual in Latin, to say that they who are