… how shall we define a science? Since I was brought up in intimacy with almost all the chief men of science in the United States during those years and was always attentive to their conversation, I think it hardly supposable that I should have mistaken what they meant by that word; and if I am right, what they meant by a science, was the total principal industry of a social group, whose whole lives, or many years of them, are consecrated to inquiries to which they are so devoted as to be drawn to every person who is pursuing similar inquiries, and these inquiries conducted according to the best methods so far found out, to which they were trained and for the prosecution of which every [one] of them possessed special advantages, their different inquiries being so nearly of the same nature that they thoroughly understood one another’s difficulties and merits, and could after a brief preparation have generally each one have taken up and carried on the other’s work, although probably not with quite his success.
It follows that the limits of a science are those of a social group, and consequently from the very nature of that sort of entity, that if our classi[fication] is to be true and yet not confused, it cannot be at all minute. For to mention only one of several insuperable difficulties, if that were attempted, it would be necessary to recognize a science that would be that of the spectroscopists, who had, and I suppose still have, their own journal and their own society. Yet every man of them must be either an inorganic chemist, or an astronomer, or a physicist inclining toward the mathematical variety, like Rowland and Michelson. But for our purpose we prefer not to make the classification at all minute.