12 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] |
| 4304 | Descartes says there are two substance, Spinoza one, and Leibniz infinitely many [Cottingham] |
| 3016 | Even the gods cannot strive against necessity [Pittacus, by Diog. Laertius] |
| 14786 | Some logical possibility concerns single propositions, but there is also compatibility between propositions [Peirce] |
| 4303 | The notion of substance lies at the heart of rationalist metaphysics [Cottingham] |
| 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] |
| 14784 | Ethics is the science of aims [Peirce] |
| 4306 | For rationalists, it is necessary that effects be deducible from their causes [Cottingham] |