to confound a number of things together, and consider many things as the same, which cannot be strictly true. This idea must therefore relate to such a connection between a number of things as determines the mind to consider them as one whole, each thing in that whole having a much nearer and more lasting connection with the rest than with anything else not included in it, so that after all the degree of connection between the parts requires to be determined by annexing the name of the thing, that is, collective idea, signified. The same causes that determine the mind to consider a number of things as the same individual, must of course imply a correspondent distinction between them and other things, not making part of that individual. The eye is not the same thing as the ear: it is a contradiction to call it so. Yet both are parts of the same body, which contains these and infinite other distinctions. The reason of this is that all the parts of the eye have evidently a distinct nature, a separate use, a greater mutual dependence on one another than on those of the ear, at the same time that the connection between the eye and ear as well as the rest of the body is still very great, compared to their connection with any other body of the same kind, which is none at all. Similarity is in general but a subordinate circumstance in determining this relation. For the eye is certainly more like the same organ in another individual than the different organs of sight and hearing are like one another in the same individual. Yet we do not, in making up the imaginary individual, associate our ideas according to this analogy, which of itself would answer no more purpose than the things themselves would, so separated and so reunited, but we think of them in that order in which they are mechanically connected together in nature, because on this order depends their power of mutually acting and reacting on each other, of acting conjointly upon other things, or of being
