'He doesn't call them bricks. Remember, they are hollow. He has taken to calling them ‘cells' . . . but you don't want to get caught up in all that nonsense. Follow me, my dear Daniel. Put thoughts of cells out of your mind. To understand the Philosophical Language you must know that all things in Earth and Heaven can be classified into forty different genera . . . within each of those, there are, of course, further subclasses.'