are suspected—sometimes, it is thought, clearly recognised—in the writings of mediæval chroniclers. The rule, then, will be to distrust all narratives conforming too closely to a set formula.
(4) The fact stated is of such a nature that it could not have been learnt by observation alone. It may be a hidden fact—a private secret, for example. It may be a fact relating to a collectivity, and applying to an extensive area or a long period of time; for example, the common act of a whole army, a custom common to a whole people or a whole age, a statistical total obtained by the addition of numerous items. It may be a comprehensive judgment on the character of a man, a group, a custom, an event. Here we have to do with propositions derived from observations by synthesis or inference: the author can only have arrived at them indirectly; he began with data furnished by observation, and elaborated them by the logical processes of abstraction, generalisation, reasoning, calculation. Two questions arise. Does it appear that the author had sufficient data to work upon? Was he accurate, or the reverse, in his use of the data he had?
On the probable inaccuracies of an author, general indications may be obtained from an examination of his writings. This examination will show us how he worked: whether he was capable of abstraction, reasoning, generalisation, and what were the mistakes he was in the habit of making. In order to determine the value of the data, we must criticise each statement separately; we must imagine the conditions under which the author observed, and ask ourselves whether he was able to procure the necessary data for his statement. This is an