explanation of this), but how it comes to exist. We know by description a vast number of things with which we never can be actually acquainted. Such, indeed, is the case with all the knowledge by which we rule our lives and conceive the reality which environs us. Yet we are absolutely dependent on the reality we know by acquaintance for all our knowledge of these things. Not only is immediate sense experience and the knowledge it gives us by acquaintance the only evidence we have of the greater and wider reality, but we are dependent on it for the terms wherewith to describe it, for the form in which to present it, for the matter with which to compose it. And this is the real ground of the study of philosophy, the justification of its standpoint. It is this fact--this ultimate undeniable fact--that all reality of whatever kind and in whatever way known, whether by thought or by feeling, whether it is perceived or conceived, remembered or imagined, is in the end composed of sense experience: it is this fact from which all the problems of philosophy arise. It is this fact that our utilitarian men of science find {20} themselves forced to recognise, however scornful they may be of metaphysical methods and results. The special problem of the nature of truth is concerned, then, with the reality that we have distinguished as known by description, and conceived by us as independent in its existence of the consciousness by which we know it. What is the nature of the seal by which we stamp this knowledge true? CHAPTER III THE LOGICAL THEORIES