The idea becomes a standpoint from which to examine existing occurrences and to see if there is not among them something which gives a hint of how communication at a distance can be effected, something to be utilized as a medium of speech at long range. The suggestion or fancy though still ideal is treated as a possibility capable of realization _in_ the concrete natural world, not as a superior reality apart from that world. As such, it becomes a platform from which to scrutinize natural events. Observed from the point of view of this possibility, things disclose properties hitherto undetected. In the light of these ascertainments, the idea of some agency for speech at a distance becomes less vague and floating: it takes on positive form. This action and reaction goes on. The possibility or idea is employed as a method for observing actual existence; and in the light of what is discovered the possibility takes on concrete existence. It becomes less of a mere idea, a fancy, a wished-for possibility, and more of an actual fact. Invention proceeds, and at last we have the telegraph, the telephone, first through wires, and then with no artificial medium. The concrete environment is transformed in the desired direction; it is idealized in fact and not merely in fancy. The ideal is realized through its own use as a tool or method of inspection, experimentation, selection and combination of concrete natural operations. Let us pause to take stock of results. The division of the world into two kinds of Being, one superior, accessible only to reason and ideal in nature, the other inferior, material, changeable, empirical, accessible to sense-observation, turns inevitably into the idea that knowledge is contemplative in nature. It assumes a contrast between theory and practice which was all to the disadvantage of the latter. But in the actual course of the development of science, a tremendous change has come about. When the practice of knowledge ceased to be dialectical and became experimental, knowing became preoccupied with changes and the test of knowledge became the ability to bring about certain changes. Knowing, for the experimental sciences, means a certain kind of intelligently conducted doing; it ceases to be contemplative and becomes in a true sense practical. Now this implies that philosophy, unless it is to undergo a complete break with the authorized spirit of science, must also alter its nature. It must assume a practical nature; it must become operative and experimental. And we have pointed out what an enormous change this transformation of philosophy entails in the two conceptions which have played the greatest rôle in historic philosophizing--the conceptions of the "real" and "ideal" respectively. The former ceases to be something ready-made and final; it becomes that which has to be accepted as the material of change, as the obstructions and the means of certain specific desired changes. The ideal and