In brief, my idea of a Man is a complex idea compounded of the ideas of all the men I have ever known and of all those I have ever imagined, knit together into a kind of unit by a close association. The author's description of the manner in which the class-association begins to be formed, is true and instructive; but does any one's idea of a man actually include all that the author {292} finds in it? By an inevitable result of the laws of association, it is impossible to form an idea of a man in the abstract; the class-attributes are always represented in the mind as part of an image of an individual, either remembered or imagined; this individual may vary from time to time, and several images of individuals may present themselves either alternatively or in succession: but is it necessary that the name should recal images of all the men I ever knew or imagined, or even all of whom I retain a remembrance? In no person who has seen or known many men, can this be the case. Apart from the ideas of the common attributes, the other ideas whether of attributes or of individual men, which enter into the complex idea, are indefinitely variable not only in kind but in quantity. Some people's complex idea of the class is extremely meagre, that of others very ample. Sometimes we know a class only from its definition, i.e. from an enumeration of its class-attributes, as in the case of an object which we have only read of in scientific books: in such a case the idea raised by the class-name will not be limited to the class-attributes, for we are unable to conceive any object otherwise than clothed with miscellaneous attributes: but these, not being derived from experience of the objects, may be such as the objects never had, nor could have; while nevertheless the class, and the class-name, answer their proper purpose; they cause us to group together all the things possessing the class-attributes, and they inform us that we may expect those attributes in anything of which that name is predicated.