This is the kitchen gardener's view, and that of the market gardener of all countries, but the fun is in calling the idea of it "grasping a principle"! At this rate makers of chessboards have strong claims to artistic merit!
No wonder that men who call a "principle" the common way of setting out kitchen and cabbage gardens from Pekin to Mortlake can see no design in the many things that go to make a beautiful landscape!
Equally stupid is the assumption, throughout the book, that the people the authors are pleased to term "landscapists" flop their houses down in the Grass, and never use low walls for dividing lines, nor terraces where necessary, never use walls for shelter or privacy, have no "order" or "balance," and presumably allow the Nettles to look in at the windows, and the cattle to have a fine time with the Carnations!