9. Nor will it be less true or certain, because moral ideas are of our own making and naming.
But it will here be
said, that if moral knowledge be placed in the contemplation of our own moral ideas, and those, as other modes,
be of our own making, What strange notions will there be of justice and temperance? What confusion of virtues
and vice, if every one may make what ideas of them he pleases? No confusion or disorder in the things
themselves, nor the reasonings about them; no more than (in mathematics) there would be a disturbance in the
demonstration, or a change in the properties of figures, and their relations one to another, if a man should make a
triangle with four corners, or a trapezium with four right angles: that is, in plain English, change the names of the
figures, and call that by one name, which mathematicians call ordinarily by another. For, let a man make to
himself the idea of a figure with three angles, whereof one is a right one, and call it, if he please, equilaterum or
trapezium, or anything else; the properties of, and demonstrations about that idea will be the same as if he called it
a rectangular triangle. I confess the change of the name, by the impropriety of speech, will at first disturb him who
knows not what idea it stands for: but as soon as the figure is drawn, the consequences and demonstrations are
plain and clear. Just the same is it in moral knowledge: let a man have the idea of taking from others, without their
consent, what their honest industry has possessed them of, and call this justice if he please. He that takes the name
here without the idea put to it will be mistaken, by joining another idea of his own to that name: but strip the idea
of that name, or take it such as it is in the speaker's mind, and the same things will agree to it, as if you called it
injustice. Indeed, wrong names in moral discourses breed usually more disorder, because they are not so easily
rectified as in mathematics, where the figure, once drawn and seen, makes the name useless and of no force. For
what need of a sign, when the thing signified is present and in view? But in moral names, that cannot be so easily
and shortly done, because of the many decompositions that go to the making up the complex ideas of those
modes. But yet for all this, the miscalling of any of those ideas, contrary to the usual signification of the words of
that language, hinders not but that we may have certain and demonstrative knowledge of their several agreements
and disagreements, if we will carefully, as in mathematics, keep to the same precise ideas, and trace them in their
several relations one to another, without being led away by their names. If we but separate the idea under
consideration from the sign that stands for it, our knowledge goes equally on in the discovery of real truth and
certainty, whatever sounds we make use of.
