Nominalists, nor abstract ideas excluding all properties not common to the class, such as Locke's famous Idea of a triangle that is neither equilateral nor isosceles nor scalene. We cannot represent to ourselves a triangle with no properties but those common to all triangles: but we may represent it to ourselves sometimes in one of those three forms, sometimes in another, being aware all the while that all of them are equally consistent with its being a triangle. One important consequence of these considerations is, that {290} the meaning of a class-name is not the same thing with the complex idea associated with it. The complex idea associated with the name man, includes, in the mind of every one, innumerable simple ideas besides those which the name is intended to mark, and in the absence of which it would not be predicated. But this multitude of simple ideas which help to swell the complex idea are infinitely variable, and never exactly the same in any two persons, depending in each upon the amount of his knowledge, and the nature, variety, and recent date of his experience. They are therefore no part of the meaning of the name. They are not the association common to all, which it was intended to form, and which enables the name to be used by all in the same manner, to be understood in a common sense by all, and to serve, therefore, as a vehicle for the communication, between one and another, of the same thoughts. What does this, is the nucleus of more closely associated ideas, which is the constant element in the complex idea of the class, both in the same mind at different times, and in different minds.