Page:Mind (New Series) Volume 15.djvu/33

 reader who seeks to approach it from the point of view of the Menschliche Weltbegriff. Petzoldt’s suggestion that Avenarius formulated his theory of vital series through examination of mental experience, and then interpreted the brain-processes in the light of such experience, is undoubtedly correct. None the less Avenarius maintains as the fundamental principle of his Kritik that the only hope of a scientific treatment of mental experience lies in the development of physiology on the lines which he has sketched. Only through a scientific understanding of the brain in its relation to environment can we acquire knowledge of the ultimate nature of experience as a whole. This part of his philosophy appears to have been formed previous to the views developed in the Menschliche Weltbegriff, and to be uncritically based on the scientific teaching prevalent in his day. Being convinced of the closed nature of the physical world, as obedient in all its changes to the principle of the conservation of energy, he asserts as ascertained fact, that consciousness can neither intervene to modify a brain-process nor emerge from it as its effect. In this respect he is a thorough-going parallelist. The body as an automaton conditions the most complex actions in the same complete manner as the merely reflex. All human activity, the highest as well as the lowest, thought as well as bodily action, can on its physiological side be interpreted in the same manner as the reflex functioning of the headless frog. The nature of brain-processes must therefore be determined without any reference to the accompanying mental activities; and as scientific method is limited to the domain marked out by the principle of the conservation of energy, only through this prior determination of the brain-processes can the mental life, which runs a parallel course, be brought within its sphere. The analogies which are established between the cerebral and the mental series co-ordinate them in the closest manner, and in their particular nature are fitted to apply