— 160 —
      §13. In fine, the defect in Naturals seems to proceed from want of
quickness, activity, and motion, in the intellectual Faculties, where-
— 161 —
by they are deprived of Reason: Whereas mad Men, on the other
side, seem to suffer by the other Extreme. For they do not appear
to me to have lost the Faculty of Reasoning: but having joined
together some Ideas very wrongly, they mistake them for Truths;
and they err as Men do, that argue right from wrong Principles.
For by the violence of their Imaginations, having taken their
Fancies for Realities, they make right deductions from them. Thus
you shall find a distracted Man fancying himself a King, with a
right inference, require suitable Attendance, Respect, and Obedi-
ence: Others who have thought themselves made of Glass, have
used the caution necessary to preserve such brittle Bodies. Hence it
comes to pass, that a Man, who is very sober, and of a right Under-
standing in all other things, may in one particular be as frantick, as
any in Bedlam ; if either by any sudden very strong impression, or
long fixing his Fancy upon one sort of Thoughts, incoherent Ideas
have been cemented together so powerfully, as to remain united.
But there are degrees of Madness, as of Folly; the disorderly
jumbling Ideas together, is in some more, and some less. In short,
herein seems to lie the difference between Idiots and mad Men,
That mad Men put wrong Ideas together, and so make wrong
Propositions, but argue and reason right from them: But Idiots
make very few or no Propositions, and reason scarce at all.
Locke Hum II, 11, §13, pp. 160-161