The bodies of our fellow-men are, of course, from one point of view complexes of presentations which we receive through our sense-organs; so far their _esse_, as Berkeley would have said, is _percipi_. But all practical communion with my fellows through the various institutions of society is based upon the conviction that, over and above their existence as presentation-complexes, or contents of my perceptive states, the bodies of my fellows have the same kind of existence as directly apprehended in immediate feeling which I ascribe to my own. In other words, all practical life is a mere illusion, unless my fellow-men are, like myself, centres of purposive experience. By the existence independent of my own perception which I ascribe to them, I mean precisely existence as feeling purposive beings. Hence, unless all social life is an illusion, there is at least one part of the physical order, external to myself, of which the _esse_ is not mere _percipi_, but _percipere_, or rather _sentire_. If my fellow-men are more than complexes of presentations or “ideas in my head,” then the subjectivist reduction of all reality to states of my “consciousness” breaks down, at least for this part of the physical order. Hence the acceptance or rejection of the subjectivist theory will ultimately depend on the nature of the evidence for the independent existence of human feelings and purposes beyond my own. On what grounds, then, do we attribute such “independent” existence as experiencing subjects to our fellows? According to the current subjectivist explanation, we have here a conclusion based on the argument from the analogy between the structure of my own body, as presented in sense-perception, and those of others. I infer that other men have a mental life like my own, because of the visible resemblances between their physical structure and my own, and this inference receives additional support from every fresh increase in our anatomical and physiological knowledge of the human frame. But, being an argument from analogy, it can never amount to a true scientific induction, and the existence of human experience, not my own, must always remain for the subjectivist a probability and can never become a certainty.