11 ideas
| 13157 | Choose the true hypothesis, which is the most intelligible one [Leibniz] |
| 5163 | Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable [Ayer] |
| 13158 | The Copernican theory is right because it is the only one offering a good explanation [Leibniz] |
| 5167 | The argument from analogy fails, so the best account of other minds is behaviouristic [Ayer] |
| 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] |
| 12165 | Romantics say music expresses ideas, or the Will, or intuitions, or feelings [Scruton] |
| 12164 | Expressing melancholy is a good thing, but arousing it is a bad thing [Scruton] |
| 5168 | Moral approval and disapproval concerns classes of actions, rather than particular actions [Ayer] |