It amused him sometimes to consider that his friends, because he had a face which did not express his feelings very vividly and a rather slow way of moving, looked upon him as strong-minded, deliberate and cool. They thought him reasonable and praised his common sense; but he knew that his placid expression was no more than a mask, assumed unconsciously, which acted like the protective colouring of butterflies; and himself was astonished at the weakness of his will. It seemed to him that he was swayed by every light emotion, as though he were a leaf in the wind, and when passion seized him he was powerless. He had no self-control. He merely seemed to possess it because he was indifferent to many of the things which moved other people. He considered with some irony the philosophy which he had developed for himself, for it had not been of much use to him in the conjuncture he had passed through; and he wondered whether thought really helped a man in any of the critical affairs of life: it seemed to him rather that he was swayed by some power alien to and yet within himself, which urged him like that great wind of Hell which drove Paolo and Francesca ceaselessly on. He thought of what he was going to do and, when the time came to act, he was powerless in the grasp of instincts, emotions, he knew not what. He acted as though he were a machine driven by the two forces of his environment and personality; his reason was someone looking on, observing the facts but powerless to interfere: it was like those gods of Epicurus, who saw the doings of men from their empyrean heights and had no might to alter one smallest particle of what occurred.