display all the ideas for this combination of texts
2 ideas
| 13097 | Force in substance makes state follow state, and ensures the very existence of substance [Leibniz] |
| Full Idea: By the force I give to substances, I understand a state from which another state follows, if nothing prevents it. ...I dare say that without force, there would be no substance. | |
| From: Gottfried Leibniz (Letters to Lelong [1712], 1712), quoted by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 7.1 | |
| A reaction: [the whole quote is interesting] This remark, more than any other I have found, places force at the centre of Leibniz's metaphysics. He is using it to resist Spinoza's one-substance view. |
| 6807 | In Newton mass is conserved, but in Einstein it can convert into energy [Bird] |
| Full Idea: According to Newton mass is conserved, while in Einstein's theory mass is not conserved but can be converted into and from energy. | |
| From: Alexander Bird (Philosophy of Science [1998]) | |
| A reaction: Perhaps this is the most fundamental difference between the theories. It certainly suggests that 'mass' was a conventional concept rather than a natural one. Maybe the relative notion of 'weight' is more natural than 'mass'. |