What then is a percept? This question, asked in this general way, is absurd. A percept appears always as a perfectly determinate, concrete content. This content is immediately given and is completely contained in the given. The only question one can ask concerning the given content is, what it is apart from perception, that is, what it is for thought. The question concerning the "what" of a percept can, therefore, only refer to the conceptual intuition which corresponds to the percept. From this point of view, the problem of the subjectivity of percepts, in the sense in which the Critical Idealists debate it, cannot be raised at all. Only that which is experienced as belonging to the subject can be termed "subjective." To form a link between subject and object is impossible for any real process, in the naïve sense of the word "real," in which it means a process which can be perceived. That is possible only for thought. For us, then, "objective" means that which, for perception, presents itself as external to the perceiving subject. As subject of perception I remain perceptible to myself after the table which now stands before me has disappeared from my field of observation. The perception of the table has produced a modification in me which persists like myself. I preserve an image of the table which now forms part of my Self. Modern Psychology terms this image a "memory-idea." Now this is the only thing which has any right to be called the idea of the table. For it is the perceptible modification of my own mental state through the presence of the table in my visual field. Moreover, it does not mean a modification in some "Ego-in-itself" behind the perceiving subject, but the modification of the perceiving subject itself. The idea is, therefore, a subjective percept, in contrast with the objective percept which occurs when the object is present in the perceptual field. The false identification of the subjective with this objective percept leads to the misunderstanding of Idealism: The world is my idea. Our next task must be to define the concept of "idea" more nearly. What we have said about it so far does not give us the concept, but only shows us where in the perceptual field ideas are to be found. The exact concept of "idea" will also make it possible for us to obtain a satisfactory understanding of the relation of idea and object. This will then lead us over the border-line, where the relation of subject to object is brought down from the purely conceptual field of knowledge into concrete individual life. Once we know how we are to conceive the world, it will be an easy task to adapt ourselves to it. Only when we know to what object we are to devote our activity can we put our whole energy into our actions. ADDITION TO THE REVISED EDITION (1918).