…I must explain in what sense I speak of a “science”, – which is an abridged expression for a heuretic science, or science aiming at the discovery of new truth. Namely, I do not mean by science, as the ancients did, that doctrine which is beyond all doubt. Nor do I use the word in the sense in which Coleridge at the beginning of the XIXth century defined science as systematized or ordered truth. But I use science in the sense of a business, that is, of a total of real acts exerting reciprocal effects one upon another, and concerned with closely analogous purposes. When I speak of any given heuretic science, I mean the body of doings in Past and Future time, not too remote from the present, of the members of a certain social group. These persons constitute a social group in their acquaintance with, understanding of, and sympathy for one another’s doings. And the peculiarity which make it a scientific group are, first, that the members are devoted to ascertaining truths of a given kind on account of their speculative interest in the matters, that they have each of them some special facilities or capacities for such research, that they employ approved methods, and that each seeks aid from the results of the others. From this point of view, the question whether a given class of investigations ought to be regarded as belonging to this science or to that is not to be settled by mere logical analysis, but is a question of fact; namely, it is the question whether the men who in our day will undertake in a scientific way investigations of the class in question will naturally mingle with one group or with another group.