"I am bound to say that it took me a long time to understand what he meant. He began by saying that everybody thought of Space as an 'empty homogeneous medium.' 'Never mind at present what the ultimate constituents of that medium are. We take it as a finished product, and we think of it as mere extension, something without any quality at all. That is the view of civilised man. You will find all the philosophers taking it for granted. Yes, but every living thing does not take that view."