We have found that our great philosophers and our great men of action are optimists. So, too, our most potent men of letters have been optimists in their books and in their lives. No pessimist ever won an audience commensurately wide with his genius, and many optimistic writers have been read and admired out of all measure to their talents, simply because they wrote of the sunlit side of life.
Source:Part III. The Practice of Optimism, Optimism: An Essay (1903)