13. Complex ideas may be distinct in one part, and confused in another.
Our complex ideas, being made up of
collections, and so variety of simple ones, may accordingly be very clear and distinct in one part, and very
obscure and confused in another. In a man who speaks of a chiliaedron, or a body of a thousand sides, the ideas of
the figure may be very confused, though that of the number be very distinct; so that he being able to discourse and
demonstrate concerning that part of his complex idea which depends upon the number of thousand, he is apt to
think he has a distinct idea of a chiliaedron; though it be plain he has no precise idea of its figure, so as to
distinguish it, by that, from one that has but 999 sides: the not observing whereof causes no small error in men's
thoughts, and confusion in their discourses.