THE framework of institutions which governs a society can in the last resort be understood only through a knowledge of the whole human environment. For though the artificial conception of man’s activities which prompts us to carve up the creature of flesh and blood into the phantoms homo oeconomicus, philosophicus, juridicus is doubtless necessary, it is tolerable only if we refuse to be deceived by it. That is why, despite the existence of other works on the various aspects of medieval civilization, the descriptions thus attempted from points of view different from ours did not seem to us to obviate the necessity of recalling at this stage the fundamental characteristics of the historical climate in which European feudalism flourished. Need I add that in placing this account near the beginning of the book there was no thought of claiming any sort of illusory primacy for facts of this kind? When it is a question of comparing two particular phenomena belonging to separate series-a certain distribution of population, for example, with certain forms of legal groups-the delicate problem of cause and effect undoubtedly arises. On the other hand, to contrast two sets of dissimilar phenomena over a period of several centuries, and then say: ‘Here on this side are all the causes; there on that are all the effects’, would be to construct the most pointless of dichotomies. A society, like a mind, is woven of perpetual interaction. For other researches, differently oriented, the analysis of the economy or the mental climate are culminating points; for the historian of the social structure they are a starting-point.