But in order to see them clearly we have to see them as a whole. We have to see how they developed as well as how they began; for the most incredible part of the story is that things which began thus should have developed thus. Any one who chooses to indulge in mere imagination can imagine that other things might have happened or other entities evolved. Any one thinking of what might have happened may conceive a sort of evolutionary equality; but any one facing what did happen must face an exception and a prodigy. If there was ever a moment when man was only an animal, we can if we choose make a fancy picture of his career transferred to some other animal. An entertaining fantasia might be made in which elephants built in elephantine architecture, with towers and turrets like tusks and trunks, cities beyond the scale of any colossus. A pleasant fable might be conceived in which a cow had developed a costume, and put on four boots and two pairs of trousers. We could imagine a Supermonkey more marvellous than any Superman, a quadrumanous creature carving and painting with his hands and cooking and carpentering with his feet. But if we are considering what did happen, we shall certainly decide that man has distanced everything else with a distance like that of the astronomical spaces and a speed like that of the still thunderbolt of the light. And in the same fashion, while we can if we choose see the Church amid a mob of Mithraic or Manichean superstitions squabbling and killing each other at the end of the Empire, while we can if we choose imagine the Church killed in the struggle and some other chance cult taking its place, we shall be the more surprised (and possibly puzzled) if we meet it two thousand years afterwards rushing through the ages as the winged thunderbolt of thought and everlasting enthusiasm; a thing without rival or resemblance; and still as new as it is old. PART I ON THE CREATURE CALLED MAN CHAPTER I THE MAN IN THE CAVE