Compared with other students the historian is in a very disagreeable situation. It is not merely that he cannot, as the chemist does, observe his facts directly; it very rarely happens that the documents which he is obliged to use represent precise observations. He has at his disposal none of those systematic records of observations which, in the established sciences, can and do replace direct observation. He is in the situation of a chemist who should know a series of experiments only from the report of his laboratory-boy. The historian is compelled to turn to account rough and ready reports, such as no man of science would be content with.[61] All the more necessary are the precautions to be taken in utilising these documents, the only materials of historical science. It is evidently most important to eliminate those which are worthless, and to ascertain the amount of correct observation represented by those which are left. All the more necessary, too, are cautions on this subject, because the natural inclination of the human mind is to take no precautions at all, and to treat these matters, which really demand the utmost obtainable precision, with careless laxity. It is true that every one admits the utility of criticism in theory; but this is just one of those principles which are more easily admitted than put into practice. Many centuries and whole eras of brilliant civilisation had to pass away before the first dawn of criticism was visible among the most intellectual peoples in the world. Neither the orientals nor the middle ages ever formed a definite conception of it.[62] Up to our own day there have been enlightened men who, in employing documents for the purpose of writing history, have neglected the most elementary precautions, and unconsciously assumed false generalisations. Even now most young students would, if left to themselves, fall into the old errors. For criticism is antagonistic to the normal bent of the mind. The spontaneous tendency of man is to yield assent to affirmations, and to reproduce them, without even clearly distinguishing them from the results of his own observation. In every-day life do we not accept indiscriminately, without any kind of verification, hearsay reports, anonymous and unguaranteed statements, "documents" of indifferent or inferior authority? It takes a special reason to induce us to take the trouble to examine into the origin and value of a document on the history of yesterday; otherwise, if there is no outrageous improbability in it, and as long as it is not contradicted, we swallow it whole, we pin our faith to it, we hawk it about, and, if need be, embellish it in the process. Every candid man must admit that it requires a violent effort to shake off _ignavia critica_, that common form of intellectual sloth, that this effort must be continually repeated, and is often accompanied by real pain.