III. Thinking in the Service of Understanding the World

When I see how a billiard ball, when struck, communicates its motion to another ball, I remain entirely without influence on the course of this event which I observe. The direction and velocity of the second ball is determined by the direction and velocity of the first. As long as I do no more than observe, I cannot say anything about the motion of the second ball until it actually moves. The situation alters if I begin to reflect on the content of my observation. The purpose of my reflection is to form concepts of the event. I bring the concept of an elastic ball into connection with certain other concepts of mechanics, and take into consideration the special circumstances prevailing in this particular instance. In other words, to the action taking place without my doing, I try to add a second action which unfolds in the conceptual sphere. The latter is dependent on me. This is shown by the fact that I could rest content with the observation and forgo all search for concepts if I had no need of them. If, however, this need is present, then I am not satisfied until I have brought the concepts ball, elasticity, motion, impact, velocity, etc., into a certain connection, to which the observed process is related in a definite way. As certain as it is that the event takes place independently of me, so certain is it also that the conceptual process cannot take place without my doing it.