Philosophers have found the chief difficulty in the explanation of ideas in the fact that we are not identical with the external objects, and yet our ideas must have a form corresponding to their objects. But on closer inspection it turns out that this difficulty does not really exist. We certainly are not identical with the external things, but we belong together with them to one and the same world. The stream of the universal cosmic process passes through that segment of the world which, to my perception, is myself as subject. So far as my perception goes, I am, in the first instance, confined within the limits bounded by my skin. But all that is contained within the skin belongs to the cosmos as a whole. Hence, for a relation to subsist between my organism and an object external to me, it is by no means necessary that something of the object should slip into me, or make an impression on my mind, like a signet-ring on wax. The question, How do I gain knowledge of that tree ten feet away from me, is utterly misleading. It springs from the view that the boundaries of my body are absolute barriers, through which information about external things filters into me. The forces which are active within my body are the same as those which exist outside. I am, therefore, really identical with the objects; not, however, I in so far as I am subject of perception, but I in so far as I am a part within the universal cosmic process. The percept of the tree belongs to the same whole as my Self. The universal cosmic process produces alike, here the percept of the tree, and there the percept of my Self. Were I a world-creator instead of a world-knower, subject and object (percept and self) would originate in one act. For they condition one another reciprocally. As world-knower I can discover the common element in both, so far as they are complementary aspects of the world, only through thought which by means of concepts relates the one to the other.