degree of reflection which this fundamental truth demands, and consequently he made it the starting-point of his philosophy, though provisionally only in the form of a sceptical doubt. When he took his cogito ergo sum as alone certain, and provisionally regarded the existence of the world as problematical, he really discovered the essential and only right starting-point of all philosophy, and at the same time its true foundation. This foundation is essentially and inevitably the subjective, the individual consciousness. For this alone is and remains immediate; everything else, whatever it may be, is mediated and conditioned through it, and is therefore dependent upon it. Therefore modern philosophy is rightly regarded as starting with Descartes, who was the father of it. Not long afterwards Berkeley followed the same path further, and attained to idealism proper, i.e., to the knowledge that the world which is extended in space, thus the objective, material world in general, exists as such simply and solely in our idea, and that it is false, and indeed absurd, to attribute to it, as such, an existence apart from all idea and independent of the knowing subject, thus to assume matter as something absolute and possessed of real being in itself. But his correct and profound insight into this truth really constitutes Berkeley's whole philosophy; in it he had exhausted himself.
Thus true philosophy must always be idealistic; indeed, it must be so in order to be merely honest. For nothing is more certain than that no man ever came out of him self in order to identify himself directly with things which are different from him; but everything of which he has certain, and therefore immediate, knowledge lies within his own consciousness. Beyond this consciousness, therefore, there can be no immediate certainty; but the first principles of a science must have such certainty. For the empirical standpoint of the other sciences it is quite right to assume the objective world as something absolutely given; but not so for the standpoint of philo-
