This is a peculiar and a highly important case of association; but not the less simple and indisputable. We have already sufficiently exemplified the two grand cases of the formation of complex ideas by association;--that in which the ideas of synchronous sensations are so concreted by constant conjunction as to appear, though numerous, only one; of which the ideas of sensible objects, a rose, a plough, a house, a ship, are examples;--and that in which the ideas of successive sensations are so concreted; of which, the idea of a { 264} tune in music, the idea of the revolution of a wheel, of a walk, a hunt, a horse-race, are instances.
It is easy to see wherein the present case agrees with, and wherein it differs from, those familiar cases. The word, man, we shall say, is first applied to an individual; it is first associated with the idea of that individual, and acquires the power of calling up the idea of him; it is next applied to another individual, and acquires the power of calling up the idea of him; so of another, and another, till it has become associated with an indefinite number, and has acquired the power of calling up an indefinite number of those ideas indifferently. What happens? It does call up an indefinite number of the ideas of individuals, as often as it occurs; and calling them up in close connexion, it forms them into a species of complex idea.
There can be no difficulty in admitting that association does form the ideas of an indefinite number of individuals into one complex idea; because it is an acknowledged fact. Have we not the idea of an army? And is not that precisely the ideas of an indefinite number of men formed into one idea? Have we not the idea of a wood, or a forest; and is not that the idea of an indefinite number of trees formed into one idea? These are instances of the concretion of synchronous ideas. Of the concretion of successive ideas indefinite in number, the idea of a concert is one instance, the idea of a discourse is another, the idea of the life of a man is another, the idea of a year, or of a century, is another, and so on. The idea, which is marked by the term "race of man," is complex in both ways, for it is not only the idea of the present generation, but of all successive generations.