But that there are forces at work which use individuals for purposes far transcending the purpose of keeping these individuals alive and prosperous and respectable and safe and happy in the middle station in life, which is all any good bourgeois can reasonably require, is established by the fact that men will, in the pursuit of knowledge and of social readjustments for which they will not be a penny the better, and are indeed often many pence the worse, face poverty, infamy, exile, imprisonment, dreadful hardship, and death. Even the selfish pursuit of personal power does not nerve men to the efforts and sacrifices which are eagerly made in pursuit of extensions of our power over nature, though these extensions may not touch the personal life of the seeker at any point. There is no more mystery about this appetite for knowledge and power than about the appetite for food: both are known as facts and as facts only, the difference between them being that the appetite for food is necessary to the life of the hungry man and is therefore a personal appetite, whereas the other is an appetite for evolution, and therefore a superpersonal need. The diverse manners in which our imaginations dramatize the approach of the superpersonal forces is a problem for the psychologist, not for the historian. Only, the historian must understand that visionaries are neither impostors nor lunatics. It is one thing to say that the figure Joan recognized as St Catherine was not really St Catherine, but the dramatization by Joan’s imagination of that pressure upon her of the driving force that is behind evolution which I have just called the evolutionary appetite. It is quite another to class her visions with the vision of two moons seen by a drunken person, or with Brocken spectres, echoes and the like. Saint Catherine’s instructions were far too cogent for that; and the simplest French peasant who believes in apparitions of celestial personages to favored mortals is nearer to the scientific truth about Joan than the Rationalist and Materialist historians and essayists who feel obliged to set down a girl who saw saints and heard them talking to her as either crazy or mendacious. If Joan was mad, all Christendom was mad too; for people who believe devoutly in the existence of celestial personages are every whit as mad in that sense as the people who think they see them. Luther, when he threw his inkhorn at the devil, was no more mad than any other Augustinian monk: he had a more vivid imagination, and had perhaps eaten and slept less: that was all. The mere Iconography does not matter.