The first fundamental rule here laid down, with respect to the mode of treating general history--namely to keep the attention fixed on the main subject, and not to let it be distracted or dissipated by a number of minute details--concerned more the method of historical science. The second rule regards the subject and purport of history, and stands in more immediate connexion with the first portion of this work--that relating to primitive history. This second fundamental rule of historical science may be thus simply expressed:--we should not wish to explain every thing. Historical tradition must never be abandoned in the philosophy of history--otherwise we lose all firm ground and footing. But historical tradition, ever so accurately conceived and carefully sifted, doth not always, especially in the early and primitive ages, bring with it a full and demonstrative certainty. In such cases, we have nothing to do but to record, as it is given, the best and safest testimony which tradition, so far as we have it, can afford; supposing even that some things in that testimony appear strange, obscure and even enigmatical; and perhaps a comparison with some other part of historical science--or, if I may so speak, stream of tradition, will unexpectedly lead to the solution of the difficulty. Extremely hazardous is the desire to explain every thing, and to supply whatever appears a gap in history--for in this propensity lies the first cause and germ of all those violent and arbitrary hypotheses which perplex and pervert the science of history far more than the open avowal of our ignorance, or the uncertainty of our knowledge: hypotheses which give an oblique direction, or an exaggerated and false extension, to a view of the subject originally not incorrect. And even if there are points which appear not very clear to us, or which we leave unexplained--this will not prevent us from comprehending, so far at least as the limited conception of man is able, the great outline of human history, though here and there a gap should remain. This matter will be best explained by an example that will bring us at once to the subject we propose to treat. Let us imagine some bold Navigators (and what we here suppose by way of example has more than once actually occurred) touching at some island inhabited by wild savages in the midst of the great ocean between America and Eastern Asia. This island lies, we suppose, at a very great distance from either Continent, and the same will hold good of it, though there be a group of islands. These savages have but miserable fishing-boats made of hollow trunks of trees, by which it is not easy to conceive how they could have been transported so far. The question now naturally occurs how has this race of men come hither?--