All evil results from the non-adaptation of constitution to conditions. This is true of everything that lives. Does a shrub dwindle in poor soil, or … - Herbert Spencer

Man needed one moral constitution to fit him for his original state; he needs another to fit him for his present state; and he has been, is, and will long continue to be, in process of adaptation. And the belief in human perfectibility merely amounts to the belief that, in virtue of this process, man will eventually become completely suited to his mode of life. Progress, therefore, is not an accident, but a necessity. Instead of civilization being artificial, it is part of nature; all of a piece with the development of the embryo or the unfolding of a flower. The modifications mankind have undergone, and are still undergoing, result from a law underlying the whole organic creation; and provided the human race continues, and the constitution of things remains the same, those modifications must end in completeness.

The preservation of health is a duty. Few seem conscious that there is such a thing as physical morality.

Old forms of government finally grow so oppressive, that they must be thrown off even at the risk of reigns of terror.