Spencer begins by arguing that the constancy of human nature, so frequently alleged, is a fallacy. For change is the law of all things, of every single object as well as of the universe. "Nature in its infinite complexity is ever growing to a new development." It would be strange if, in this universal mutation, man alone were unchangeable, and it is not true. "He also obeys the law of indefinite variation." Contrast the houseless savages with Newtons and Shakespeares; between these extremes there are countless degrees of difference. If then humanity is indefinitely variable, perfectibility is possible. In the second place, evil is not a permanent necessity. For all evil results from the non-adaptation of the organism to its conditions; this is true of everything that lives. And it is equally true that evil perpetually tends to disappear. In virtue of an essential principle of life, this non-adaptation of organisms to their conditions is ever being rectified, and one or both continue to be modified until the adaptation is perfect. And this applies to the mental as well as to the physical sphere. In the present state of the world men suffer many evils, and this shows that their characters are not yet adjusted to the social state. Now the qualification requisite for the social state is that each individual shall have such desires only as may fully be satisfied without trenching upon the ability of others to obtain similar satisfaction. This qualification is not yet fulfilled, because civilised man retains some of the characteristics which were suitable for the conditions of his earlier predatory life. He needed one moral constitution for his primitive state, he needs quite another for his present state. The resultant is a process of adaptation which has been going on for a long time, and will go on for a long time to come. Civilisation represents the adaptations which have already been accomplished. Progress means the successive steps of the process. That by this process man will eventually become suited to his mode of life, Spencer has no doubts. All excess and deficiency of suitable faculties must disappear; in other words, all imperfection. "The ultimate development of the ideal man is logically certain--as certain as any conclusion in which we place the most implicit faith; for instance, that all men will die." Here is the theory of perfectibility asserted, on new grounds, with a confidence not less assured than that of Condorcet or Godwin.