display all the ideas for this combination of texts
3 ideas
| 23670 | Scientists don't know the cause of magnetism, and only discover its regulations [Reid] |
| 23671 | Laws are rules for effects, but these need a cause; rules of navigation don't navigate [Reid] |
| 21219 | Find the essence by varying an object, to see what remains invariable [Velarde-Mayol] |