single impression.
Analysis and critical questioning will then have become a matter of instinct, and we shall have acquired for ever that methodically analytical, distrustful, not too respectful turn of mind which is often mystically called "the critical sense," but which is nothing else than an unconscious habit of criticism.
CHAPTER VIII
THE DETERMINATION OF PARTICULAR FACTS
Critical analysis yields in the result a number of conceptions and statements, accompanied by comments on the probability of the facts stated being accurate. It remains to examine how we can deduce from these materials those particular historical facts which are to form the basis of scientific knowledge. Conceptions and statements are two different kinds of results, and must be treated by different methods.
I. Every conception which is expressed in writing or by any illustrative representation is in itself a definite, unimpeachable fact That which is expressed must have first been present in the mind of some one—if not in that of the author, who may have reproduced a formula he did not understand, then in the mind of the man who originated the formula. The existence of a conception may be learnt from a single instance and proved from a single document. Analysis and interpretation are thus sufficient for the purpose of drawing up the complete list of those facts which form the basis of the history of the arts, the sciences, or of doctrines. It is the task of external criticism to localise these facts by determining the epoch, the country, the author of each conception. The duration, geographical distribution, origin, and filiation of conceptions belong to historical synthesis. Internal criticism has nothing to do here; the fact is taken directly from the document.
We may advance