Now it is worth while to pause upon that story because, as has been suggested, it directly contradicts the impression still current that nomadism is merely a prehistoric thing and social settlement a comparatively recent thing. There is nothing to show that the Babylonians had ever wandered; there is very little to show that the tribes of the desert ever settled down. Indeed it is probable that this notion of a nomadic stage followed by a static stage has already been abandoned by the sincere and genuine scholars to whose researches we all owe so much. But I am not at issue in this book with sincere and genuine scholars, but with a vast and vague public opinion which has been prematurely spread from certain imperfect investigations, and which has made fashionable a false notion of the whole history of humanity. It is the whole vague notion that a monkey evolved into a man and in the same way a barbarian evolved into a civilised man, and therefore at every stage we have to look back to barbarism and forward to civilisation. Unfortunately this notion is in a double sense entirely in the air. It is an atmosphere in which men live rather than a thesis which they defend. Men in that mood are more easily answered by objects than by theories; and it will be well if any one tempted to make that assumption, in some trivial turn of talk or writing, can be checked for a moment by shutting his eyes and seeing for an instant, vast and vaguely crowded, like a populous precipice, the wonder of the Babylonian wall.