On the hundredth anniversary of Darwin's The Origin of Species, we are reminded once again of the perennial power and intellectual appeal of concepts of evolution. And although Darwin's view was not the first, his concept of the evolution of biological organisms quickened the interest of other scientists and philosophers in making evolutionary theories to account for long-range natural processes of various kinds not restricted to biology. In fact, both in Darwin's theories and in a number of theories in other fields, an implicit general concept of evolution may be detected. The aim of this paper is to explicate¹ this general concept of evolution. Before doing so, however, we shall begin by characterizing it informally.