In the evolutionary theories of modern biology, it is precisely the problems of the origination of new _species_, and of the special character of the relations between the species and its environment by which this process is conditioned, that have attracted almost exclusive attention. And, with the steadily increasing success of evolutionary hypotheses in dealing with biological problems, there has naturally arisen a tendency to extend the application of the general concept of evolution far beyond the sphere in which it first originated. We have now not only more or less well-accredited hypotheses of the production by evolution of our chemical elements, but even ambitious philosophical constructions which treat the concept of evolution as the one and only key to all the problems of existence. In the presence of these far-reaching applications of evolutionary ideas, it becomes all the more necessary to bear in mind, in our estimate of the worth of the evolution concept, that its logical character remains unaltered by the extension of its sphere of applicability; it is still, in spite of all minor modifications, essentially an attempt to interpret natural processes in general in terms of individual growth. We are not, of course, in the present chapter in any way concerned with the details of any one particular theory as to the special conditions which determine the course of organic or other evolution. What those conditions in any special case are, is a question, in the first instance, for that particular branch of empirical science which deals with the description of the particular aspect of the processes of the physical order under investigation. And though it would be a proper question for a complete Philosophy of Nature how the details of a well-established scientific theory must be interpreted so as to harmonise with the general metaphysical implications of the physical order, it is for many reasons premature to raise such a question in the present state of our actual knowledge of the details of evolutionary processes. All that can be done here is to ask what in general are the logical implications involved in thinking of a process as an evolution at all, and how those implications are related to our general interpretation of the physical order.