[1] In explaining mental pictures, philosophers have found the chief difficulty in the fact that we ourselves are not the outer things, and yet our mental pictures must have a form corresponding to the things. But on closer inspection it turns out that this difficulty does not really exist. We certainly are not the external things, but we belong together with them to one and the same world. That section of the world which I perceive to be myself as subject is permeated by the stream of the universal cosmic process. To my perception I am, in the first instance, confined within the limits bounded by my skin. But all that is contained within this 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 get information about 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 things filters into me. The forces which are at work inside my body are the same as those which exist outside. Therefore I really am the things; not, however, "I" in so far as I am a percept of myself as subject, but "I" in so far as I am a part of the universal world process. The percept of the tree belongs to the same whole as my I. This universal world process produces equally the percept of the tree out there and the percept of my I in here. Were I not a world knower, but world creator, object and subject (percept and I) would originate in one act. For each implies the other. In so far as these are entities that belong together, I can as world knower discover the common element in both only through thinking, which relates one to the other by means of concepts.