The root formula of an epoch is always an unwritten law, just as the law that is the first of all laws, that which protects life from the murderer, is written nowhere in the Statute Book. Nevertheless there is all the difference between having and not having a notion of this basic assumption in an epoch. For instance, the Middle Ages will simply puzzle us with their charities and cruelties, their asceticism and bright colours, unless we catch their general eagerness for building and planning, dividing this from that by walls and fences--the spirit that made architecture their most successful art. Thus even a slave seemed sacred; the divinity that did hedge a king, did also, in one sense, hedge a serf, for he could not be driven out from behind his hedges. Thus even liberty became a positive thing like a privilege; and even, when most men had it, it was not opened like the freedom of a wilderness, but bestowed, like the freedom of a city. Or again, the seventeenth century may seem a chaos of contradictions, with its almost priggish praise of parliaments and its quite barbaric massacre of prisoners, until we realise that, if the Middle Ages was a house half built, the seventeenth century was a house on fire. Panic was the note of it, and that fierce fastidiousness and exclusiveness that comes from fear. Calvinism was its characteristic religion, even in the Catholic Church, the insistence on the narrowness of the way and the fewness of the chosen. Suspicion was the note of its politics--"put not your trust in princes." It tried to thrash everything out by learned, virulent, and ceaseless controversy; and it weeded its population by witch-burning. Or yet again: the eighteenth century will present pictures that seem utterly opposite, and yet seem singularly typical of the time: the sack of Versailles and the "Vicar of Wakefield"; the pastorals of Watteau and the dynamite speeches of Danton. But we shall understand them all better if we once catch sight of the idea of _tidying up_ which ran through the whole period, the quietest people being prouder of their tidiness, civilisation, and sound taste than of any of their virtues; and the wildest people having (and this is the most important point) no love of wildness for its own sake, like Nietzsche or the anarchic poets, but only a readiness to employ it to get rid of unreason or disorder. With these epochs it is not altogether impossible to say that some such form of words is a key. The epoch for which it is almost impossible to find a form of words is our own.