38 ideas
| 7823 | Lucretius was rediscovered in 1417 [Grayling] |
| 22304 | Truth is conceivability, or the systematic coherence of a significant whole [Joachim] |
| 1553 | No perceptible object is truly straight or curved [Protagoras] |
| 6408 | Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling] |
| 1549 | Everything that exists consists in being perceived [Protagoras] |
| 6414 | Two propositions might seem self-evident, but contradict one another [Grayling] |
| 1545 | Protagoras was the first to claim that there are two contradictory arguments about everything [Protagoras, by Diog. Laertius] |
| 1547 | Man is the measure of all things - of things that are, and of things that are not [Protagoras] |
| 3305 | There is no more purely metaphysical doctrine than Protagorean relativism [Benardete,JA on Protagoras] |
| 3313 | If my hot wind is your cold wind, then wind is neither hot nor cold, and so not as cold as itself [Benardete,JA on Protagoras] |
| 3317 | You can only state the problem of the relative warmth of an object by agreeing on the underlying object [Benardete,JA on Protagoras] |
| 247 | God is "the measure of all things", more than any man [Plato on Protagoras] |
| 606 | Protagoras absurdly thought that the knowing or perceiving man is 'the measure of all things' [Aristotle on Protagoras] |
| 612 | Relativists think if you poke your eye and see double, there must be two things [Aristotle on Protagoras] |
| 7091 | The argument from analogy is not a strong inference, since the other being might be an actor or a robot [Grayling] |
| 7293 | It is legitimate to do harm if it is the unintended side-effect of an effort to achieve a good [Grayling] |
| 6016 | Early sophists thought convention improved nature; later they said nature was diminished by it [Protagoras, by Miller,FD] |
| 1580 | For Protagoras the only bad behaviour is that which interferes with social harmony [Protagoras, by Roochnik] |
| 205 | Protagoras contradicts himself by saying virtue is teachable, but then that it is not knowledge [Plato on Protagoras] |
| 7809 | In an honour code shame is the supreme punishment, and revenge is a duty [Grayling] |
| 23262 | Experience, sympathy and history are sensible grounds for laying claim to rights [Grayling] |
| 23263 | Politics is driven by power cliques [Grayling] |
| 23255 | It is essential for democracy that voting is free and well informed [Grayling] |
| 23254 | Democracies should require a supermajority for major questions [Grayling] |
| 23260 | A cap on time of service would restrict party control and career ambitions [Grayling] |
| 23253 | Majority decisions are only acceptable if the minority interests are not vital [Grayling] |
| 23256 | Liberty and equality cannot be reconciled [Grayling] |
| 23258 | The very concept of democracy entails a need for justice [Grayling] |
| 23259 | There should be separate legislative, executive and judicial institutions [Grayling] |
| 1659 | Protagoras seems to have made the huge move of separating punishment from revenge [Protagoras, by Vlastos] |
| 7292 | War must also have a good chance of success, and be waged with moderation [Grayling] |
| 532 | Successful education must go deep into the soul [Protagoras] |
| 1552 | He spent public money on education, as it benefits the individual and the state [Protagoras, by Diodorus of Sicily] |
| 7824 | If suicide is lawful, but assisting suicide is unlawful, powerless people are denied their rights [Grayling] |
| 1551 | He said he didn't know whether there are gods - but this is the same as atheism [Diogenes of Oen. on Protagoras] |
| 7819 | Religion gives answers, comforts, creates social order, and panders to superstition [Grayling] |
| 7817 | To make an afterlife appealing, this life has to be denigrated [Grayling] |
| 7818 | In Greek mythology only heroes can go to heaven [Grayling] |