12 ideas
| 579 | Cratylus said you couldn't even step into the same river once [Cratylus, by Aristotle] |
| 5163 | Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable [Ayer] |
| 578 | Cratylus decided speech was hopeless, and his only expression was the movement of a finger [Cratylus, by Aristotle] |
| 5167 | The argument from analogy fails, so the best account of other minds is behaviouristic [Ayer] |
| 14802 | Physical and psychical laws of mind are either independent, or derived in one or other direction [Peirce] |
| 5164 | A statement is meaningful if observation statements can be deduced from it [Ayer] |
| 5165 | Directly verifiable statements must entail at least one new observation statement [Ayer] |
| 5166 | The principle of verification is not an empirical hypothesis, but a definition [Ayer] |
| 5162 | Sentences only express propositions if they are meaningful; otherwise they are 'statements' [Ayer] |
| 5168 | Moral approval and disapproval concerns classes of actions, rather than particular actions [Ayer] |
| 14800 | The world is full of variety, but laws seem to produce uniformity [Peirce] |
| 14801 | Darwinian evolution is chance, with the destruction of bad results [Peirce] |