s; he is insane whose mind is not
sound, but is deranged, and therefore, like a machine out of order, it
cannot properly perform its specific task, namely, to know the truth of
things. An insane man cannot judge rightly.

1. Insanity takes various forms, which may be reduced to two kinds, with
the doubtful addition of a third kind, namely, moral insanity, of which
we shall speak in our next lecture.

The first kind consists in the total want or gross torpor of mental
activity. When there is a total, or nearly total, eclipse of the
intellect, the disease is called _idiocy_, the state of an idiot. When
there is an abnormally low grade of the reasoning power, it is styled
_imbecility_. The failure or decay of reason in old age is called
_dotage_.

The second kind of insanity is called _illusional_ or _delusional_. In
it the intellect is not impotent; on the contrary, it is often unusually
active; but its action is abnormal, its conclusions are false. Not that
it reasons illogically or draws conclusions which are not contained in
the premises. Very keen logicians may be demented. Their unsoundness
arises from the fact that they reason from false premises; and they get
their false premises from their diseased imaginations, whose vagaries
they take for realities.

2. Here a difficulty presents itself, which we must explain at once,
namely, how can there be unsoundness of mind at all? Is not the
intellect of man a simple power, and his soul a simple being? How can a
simple being become deranged? Can that which has no parts become
disarranged, disorganized? I answer, the soul is a simple being, its
intellect is a spiritual faculty; and therefore we never say that the
_soul_ is insane, nor should we say that the _intellect_ is insane or
diseased; but we say that the _mind_ is deranged or insane; the mind
comprises more than the intellect; it designates the intellect together
with those lower powers that supply the materials for our thought, the
chief of which is the imagination. Now the imagination is an organic
faculty: it works in and by a bodily organism, which is the brain.
Therefore, when the brain is not in a normal condition, the action of
the imagination may be disordered. And the intellect or understanding of
the spiritual soul is so closely united in its action and its very being
with the organic body that the two ever act conjointly, like the two
wheels of a vehicle. If one wheel breaks down, the other is thrown o