3 ideas
| 23217 | All of our happiness and misery arises entirely from the brain [Hippocrates] |
| 7634 | Icons resemble their subject, an index is a natural sign, and symbols are conventional [Peirce, by Maund] |
| 9425 | Lewis later proposed the axioms at the intersection of the best theories (which may be few) [Mumford on Lewis] |