5 ideas
| 19389 | Truth is a characteristic of possible thoughts [Leibniz] |
| 19388 | True and false seem to pertain to thoughts, yet unthought propositions seem to be true or false [Leibniz] |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| 20645 | Heat is a state of vibration, not a substance [Joule] |
| 20972 | Joule showed that energy converts to heat, and heat to energy [Joule, by Papineau] |