observed and recorded. Because a fact has not been recorded it does not follow that it has not been observed. Any one who is concerned in an organisation for the collection of a particular species of facts knows how much commoner those facts are than people think, and how many cases pass unnoticed or without leaving any written trace. It is so with earthquakes, cases of hydrophobia, whales stranded on the shore. Besides, many facts, even those which are well known to those who are contemporary with them, are not recorded, because the official authorities prevent their publication; this is what happens to the secret acts of governments and the complaints of the lower classes. This silence, which proves nothing, greatly impresses unreflecting historians; it is the origin of the widespread sophism of the "good old times." No document relates any abuse of power by officials or any complaints made by peasants; therefore, everything was regular and nobody was suffering. Before we argue from silence we should ask: Might not this fact have failed to be recorded in any of the documents we possess? That which is conclusive is not the absence of any document on a given fact, but silence as to the fact in a document in which it would naturally be mentioned.
The negative argument is thus limited to a few clearly defined cases. (1) The author of the document in which the fact is not mentioned had the intention of systematically recording all the facts of the same class, and must have been acquainted with all of them. (Tacitus sought to enumerate the peoples of Germany; the Notitia dignitatum mentioned all the provinces of the Empire; the absence from these lists of