What I have said up to now is intended to explain why I shall be interlarding my lecture with the images and parables so necessary to you. I do not need them myself; in this I discern no sign of my superiority—that lies elsewhere. The countervisuality of my nature derives from the fact that I have never held a stone in my hand or plunged into slimy-green or crystal-clear water, nor did I first learn of the existence of gases with my lungs in the early morning, but only later by calculations, since I have neither hands for grasping, nor a body, nor lungs. Therefore abstraction is primary for me, while the visual is secondary, and I have had to learn the latter with considerably more effort than was required for me to learn abstraction. Yet I needed this, if I was to erect those precarious bridges across which my thought travels to you, and across which, reflected in your intellects, it returns to me, usually to surprise me.