Here's another quote from Human, All Too Human:
The party man. -- The genuine party man no longer learns, he only experiences things and judges them: whereas Solon, who was never a party man but pursued his aims beside and above the parties or in opposition to them, is significantly the father of that simple saying in which there lies enclosed the health and inexhaustibility of Athens: "I grow old and still I go on learning." (Volume 2, Part 1, ยง301)