If they seem so to grown men, it is only because by constant and familiar use they are made so.

For, when we nicely reflect upon them, we shall find that GENERAL IDEAS are fictions and contrivances of the mind, that carry difficulty with them and do not so easily offer themselves as we are apt to imagine.

For example, does it not require some pains and skill to form the general idea of a triangle,( which is yet none of the more abstract, comprehensive, and difficult,) for it must be neither oblique nor rectangle, neither equilateral, equicrural, nor scalinon; but all and none of these at once.

In effect, it is something imperfect, that cannot exist; an idea wherein some part of several different and inconsistant ideas are put together.

It is true, the mind, in this imperfect state, has need of such ideas, and makes all the haste to them it can, for the conveniency of communication and enlargement of knowledge; to both which it is naturally very much inclined.