It was because Cézanne could come at reality only through what he saw that he never invented purely abstract forms. Few great artists have depended more on the model. Every picture carried him a little further towards his goal-complete expression; and because it was not the making of pictures but the expression of his sense of the significance of form that he cared about, he lost interest in his work so soon as he had made it express as much as he had grasped. His own pictures were for Cézanne nothing but rungs in a ladder at the top of which would be complete expression. The whole of his later life was a climbing towards an ideal. For him every painting was a means, a step, a stick, a hold, a stepping-stone-something he was ready to discard as soon as it had served his purpose. He had no use for his own pictures. To him they were experiments. He tossed them into bushes, or left them in the open fields to be stumbling-blocks for a future race of luckless critics.