15 ideas
| 14782 | Philosophy is an experimental science, resting on common experience [Peirce] |
| 14787 | Self-contradiction doesn't reveal impossibility; it is inductive impossibility which reveals self-contradiction [Peirce] |
| 14783 | Logic, unlike mathematics, is not hypothetical; it asserts categorical ends from hypothetical means [Peirce] |
| 14788 | Mathematics is close to logic, but is even more abstract [Peirce] |
| 304 | Beautiful things must be different from beauty itself, but beauty itself must be present in each of them [Plato] |
| 14786 | Some logical possibility concerns single propositions, but there is also compatibility between propositions [Peirce] |
| 16120 | Knowing how to achieve immortality is pointless without the knowledge how to use immortality [Plato] |
| 14789 | Experience is indeed our only source of knowledge, provided we include inner experience [Peirce] |
| 14785 | The world is one of experience, but experiences are always located among our ideas [Peirce] |
| 303 | Say how many teeth the other has, then count them. If you are right, we will trust your other claims [Plato] |
| 14784 | Ethics is the science of aims [Peirce] |
| 302 | What knowledge is required to live well? [Plato] |
| 301 | Only knowledge of some sort is good [Plato] |
| 305 | Something which lies midway between two evils is better than either of them [Plato] |
| 6004 | The cardinal virtues are theoretical (based on knowledge), and others are 'non-theoretical' [Hecato, by Dorandi] |