Lecture IV

Take a concrete example, the first phenomenon that confronts us after the birth of scientific thinking, the Copernican system. It is not my intention today or in any of these lectures to defend either the Ptolemaic or the Copernican system. I am not advocating either one. I am only speaking of the historical fact that the Copernican system has replaced the Ptolemaic. What I say today does not imply that I favor the old Ptolemaic system over the Copernican. But this must be said as a matter of history. Imagine yourself back in the age when man experienced his own orientation in space: above-below, right-left, front-back. He could experience this only in connection with the earth. He could, for example, experience the vertical orientation in himself only in relation to the direction of gravity. He experienced the other two in connection with the four compass points according to which the earth itself is oriented. All this he experienced together with the earth as he felt himself standing firmly on it. He thought of himself not just as a being that begins with the head and ends a the sole of the feet. Rather, he felt himself penetrated by the force of gravity, which had something to do with his being but did not cease at the soles of his feet. Hence, feeling himself within the nature of the gravitational force, man felt himself one with the earth. For his concrete experience, the starting point of his cosmology was thus given by the earth. Therefore he felt he Ptolemaic system to be justified.