But this is not the only process which goes on. Every aspect of a question must be looked at from a different point of view; unless one does so from at least two points of view, one will always have difficulty in understanding it fully. If one watches the work of the potter one sees that he kneads the clay, colors it, and then molds it into the different vessels he wants to make. As long as he has enough different clays and colors at hand he does not begin his work every time by again fetching clay and then kneading and coloring it. In the same way one sees that vegetable matter comes from the vegetable kingdom and that man comes from man.