The "Philosophy of Evolution," which forms the topic of the present lecture, is in no sense a finished doctrine, nor is it, on its philosophical side, a very elaborate doctrine. It consists of a criticism and formulation of the presuppositions that are characteristic of an age whose interest in outer nature is mainly an historical interest. The thought of the present century differs from that of the Seventeenth Century chiefly in this prominence of the historical study of the world. For the Seventeenth Century the world was the embodiment of eternal laws; it was a mechanical universe, where all was merely necessary, and where, in consequence, nothing having a narrative importance occurred. The present world also believes in a mechanical order of nature, but has superposed upon this mechanical view an historical, and consequently an essentially idealistic and teleological interpretation of nature's mechanism. To bring this fact to consciousness, to define and to defend this historical interpretation, is the whole task that properly falls to the lot of a "Philosophy of Evolution." As for the particular truths about the actual process of evolution, it is the business of empirical study to find them out. That there is genuine, and not merely apparent history in the world, philosophy must undertake to show if it can. What the history of this or that in the world is, only science can determine.
Such being the general point of view of the lecture, the particular topics next discussed were: (1) The objection that the modern doctrine of evolution, in assigning a "low origin" to all significant things, deprives the world of all higher and ideal significance. (2) The objection that empirical students of evolution are often unaware of the teleological and ideal nature of their own presuppositions, so that it seems doubtful whether their presuppositions actually have this ideal character. To both these objections the same response was made. The doctrine of evolution has its purely naturalistic as well as its teleological side; it is essentially "Applied idealism" and as thus applied to or superposed upon a mechanical view of nature, it must, like the Seventeenth Century philosophy, assign "low origin" to ideal things. Only the important matter for philosophy is that the "low origin," the mechanical aspect of nature, does not forbid for our modern doctrine the interpretation of nature in teleological terms. The mechanism embodies purposes.
The defence, now, of this presupposition can only be given from an idealistic point of view. The lecture therefore suggested afresh the "double aspect" which Idealism gives to Reality, and set forth on this basis a hypothetical scheme of the process of the evolution of finite minds on this planet.
The lecture concluded with a general and negative criticism of the Spencerian formulas of evolution, and with a few practical suggestions as to the ethical aspect of the doctrine of evolution.