If thought exists, I who think and the world about which I think also exist; the one exists but for the other, having no possible separation between them. Therefore, the world and I are both in active correlation; I am that which sees the world, and the world is that which is seen by me. I exist for the world and the world exists for me. … One sure and primary and fundamental fact is the joint existence of a subject and of its world. The one does not exist without the other. I acquire no understanding of myself except as I take account of objects, of the surroundings. I do not think unless I think of things — and there I find myself.

p. 21 - Striking Thoughts (2000)