13 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] |
| 12695 | Epicurean atomists say body is sensible, to distinguish it from space. [Garber] |
| 14786 | Some logical possibility concerns single propositions, but there is also compatibility between propositions [Peirce] |
| 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] |
| 21991 | The middle class gain freedom through property, but workers can only free all of humanity [Marx, by Singer] |
| 21990 | Theory is as much a part of a revolution as material force is [Marx] |
| 12705 | Epicurean atoms are distinguished by their extreme hardness [Garber] |
| 7128 | Religion is the opium of the people, and real happiness requires its abolition [Marx] |