Page:Theory of Mind of Roger Bacon.djvu/45

 spurs in the fight, and from the very pride of victory (which of course carried with it the idea of the possession of large spurs) forthwith grew new spurs. And he shows us how novel the thought was to him, by further quoting that hot and cold come not from hot and cold in the external world, but from the mere thought of the mind; and so it is that sickness arises, and every change in the body of any given soul! This odd transition from the one world into the other, with a kind of abandoned license, makes it plain that the ideas were novel to him, and that he had not thought out the details in their consequences. Again, it is the same difficulty of interaction between two wholly different worlds.

And we have this same unclarified difficulty with reference to the action of the Angels in producing the movements of the Heavens. For, the Angels are purely spiritual Intelligences, and motion is a concept which has meaning only in the purely corporeal world. The Angels cannot be spoken of as moving from place to place; and as little should they be spoken of as moving something else, that is some corporeal thing, from place to place.

The difficulty meets us then again and again. But even where this difficulty is not present, it would seem evident that Bacon had not considered with care the details of the application of his theory. To take the case of infection. He speaks of the vapors and the spirits and the Species coming from persons, all as though they were fused in his mind into one and the same thing. As such he conceives of them as passing from one individual to another. And again, he conceives of these same vicious Species, when they come from venomous reptiles, as capable of being reflected by mirrors in the same way that rays of light are reflected by mirrors; with mathematical skill they can be directed at will, to work injury, for example, in an enemy’s camp.

It is plain then that there remained for the application of his theory the difficulty of interaction; and that with the details of the application of his theory he was less concerned than with the fixing of its outlines. By confining himself to certain clear mental images, he was enabled to think with force and consistency within certain limits. But beyond these limits his theory was fluid and indefinite. But to have actually risen to so lofty and bold a conception, broad and general though it be, was an extraordinary accomplishment for a thinker of the thirteenth century. And one who seeks to fill in the details which Bacon failed to work out, comes to realize full well what wealth of patient and clear and profound thought our philosopher spent on his structure. In the chapters that follow we shall consider in fuller detail certain applications of this interesting theory.