More from Socrates
- The Apology of Socrates (399 BC)
More about knowledge
- ?UnattributedOften credited to Albert Einstein
Benjamin Franklin1706–1790Ben Franklin, as quoted in Exercises in English Grammar (1909) by M. A. Morse.There are three things extremely hard: steel, a diamond, and to know one’s self.
Benjamin Franklin1706–1790John Maxwell Failing Forward: How to Make the Most of Your Mistakes, Thomas Nelson Inc, 8 March 2000, p. 65.

