4 ideas
| 15381 | Dyamic logics model changes between classical states, in action, belief, and computing [Uckelman] |
| Full Idea: Dynamic logic gives versions of propositional, modal and predicate logics, in which the states are classical, but changes of assignments between states can be expressed, by modelling action, knowledge and belief change, and compute programs. | |
| From: Sara L. Uckelman (Dynamic Logics [2010]) | |
| A reaction: [compressed] |
| 13432 | The essence of a circle is the equality of its radii [Leibniz] |
| Full Idea: The essence of a circle consists in the equality of all lines drawn from its centre to its circumference. | |
| From: Gottfried Leibniz (Letters to Thomasius [1669], 1669) | |
| A reaction: Compare Locke in Idea 13431 and Spinoza in Idea 13073 on the essence of geometrical figures. A key question is whether the essence is in the simplest definition, or in a complex and wide-ranging account, e.g. including conic sections for circles. |
| 490 | Everything happens by reason and necessity [Leucippus] |
| Full Idea: Nothing happens at random; everything happens out of reason and by necessity. | |
| From: Leucippus (fragments/reports [c.435 BCE], B002), quoted by (who?) - where? |
| 12696 | Bodies are recreated in motion, and don't exist in intervening instants [Leibniz] |
| Full Idea: I have demonstrated that whatever moves is continuously created and that bodies are nothing at any time between the instants in motion. | |
| From: Gottfried Leibniz (Letters to Thomasius [1669], 1669.04), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 1 | |
| A reaction: Leibniz is a little over-confident about what he has 'demonstrated', but I think (from this remark) that he would not have been displeased with quantum theory, and the notion of a 'quantum leap' and a 'Planck time'. A 'conatus' is a 'smallest motion'. |