While the scientist, on the one hand, is concerned with giving a faithful description of facts, on the other, he has the equally important task of construing them in relation to some explanatory conjecture. Similarly the historian has a double duty: both of reporting the past as nearly as possible as it passed or was lived through by men at the time (without doctoring up events to fit later developments or some more "enlightened reading" of them); and second, of interpreting their import in the light of a present hypothesis.