4 ideas
| 19404 | Necessities rest on contradiction, and contingencies on sufficient reason [Leibniz] |
| 16519 | No one can conceive of a possible substance, apart from those which God has created [Arnauld] |
| 8113 | Art is like understanding a natural language, and needs a grasp of a symbol system [Goodman, by Gardner] |
| 19403 | Each of the infinite possible worlds has its own laws, and the individuals contain those laws [Leibniz] |