Such is the overwhelming certitude of philosophic insight that it does not need any other support to justify its truth for itself. Its possessor may, if he wishes, for the sake of others, put in such a support when attempting to communicate with them in words: but for himself it is not at all necessary. It is in a class entirely by itself and leaves the possessor with such awe, such a feeling of homage to its reality and truth, that he will be loath to mention it in any ordinary gathering of men.
-- Notebooks Category 20: What Is Philosophy? > Chapter 4: Its Realization Beyond Ecstasy > # 158