5 ideas
291 | Don't assume that wisdom is the automatic consequence of old age [Plato] |
9565 | Zermelo made 'set' and 'member' undefined axioms [Zermelo, by Chihara] |
3339 | For Zermelo's set theory the empty set is zero and the successor of each number is its unit set [Zermelo, by Blackburn] |
12697 | Indivisibles are not parts, but the extrema of parts [Leibniz] |
293 | Being unafraid (perhaps through ignorance) and being brave are two different things [Plato] |