"Nature is spoken of in two ways: in one way it is nature as matter, in the other it is nature as being. And the latter is also nature as moving cause and as end. and such, in the animal, is either its whole soul or some part of it. So in this way the student of nature will actually have to speak more about soul than about matter, in proportion as it is more due to soul that the matter is nature than the other way round. For the timber too is bed and stool in that is potentially these."