5 ideas
| 9463 | Classical logic is bivalent, has excluded middle, and only quantifies over existent objects [Jacquette] |
| Full Idea: Classical logic (of Whitehead, Russell, Gödel, Church) is a two-valued system of propositional and predicate logic, in which all propositions are exclusively true or false, and quantification and predication are over existent objects only. | |
| From: Dale Jacquette (Intro to I: Classical Logic [2002], p.9) | |
| A reaction: All of these get challenged at some point, though the existence requirement is the one I find dubious. |
| 19400 | Possibles demand existence, so as many of them as possible must actually exist [Leibniz] |
| Full Idea: From the conflict of all the possibles demanding existence, this at once follows, that there exists that series of things by which as many of them as possible exist. | |
| From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.91) | |
| A reaction: I'm in tune with a lot of Leibniz, but my head swims with this one. He seems to be a Lewisian about possible worlds - that they are concrete existing entities (with appetites!). Could Lewis include Leibniz's idea in his system? |
| 19401 | God's sufficient reason for choosing reality is in the fitness or perfection of possibilities [Leibniz] |
| Full Idea: The sufficient reason for God's choice can be found only in the fitness (convenance) or in the degree of perfection that the several worlds possess. | |
| From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.92) | |
| A reaction: The 'fitness' of a world and its 'perfection' seem very different things. A piece of a jigsaw can have wonderful fitness, without perfection. Occasionally you get that sinking feeling with metaphysicians that they just make it up. |
| 19402 | The actual universe is the richest composite of what is possible [Leibniz] |
| Full Idea: The actual universe is the collection of the possibles which forms the richest composite. | |
| From: Gottfried Leibniz (Exigency to Exist in Essences [1690], p.92) | |
| A reaction: 'Richest' for Leibniz means a maximum combination of existence, order and variety. It's rather like picking the best starting team from a squad of footballers. |
| 22306 | To explain false belief we should take belief as relating to a proposition's parts, not to the whole thing [Russell] |
| Full Idea: To explain belief in what is false we shall have to regard what is called belief in a proposition as not a thought related to the proposition, but rather as a thought related to the constituents of the proposition. | |
| From: Bertrand Russell (Papers of 1906 [1906], V.321), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 40 '1906' | |
| A reaction: Russell proposed a new theory of judgement, in order to explain erroneous judgements, given that true propositions are identical with facts. Of course there might be errors about the constituents, as well as about their structure. Othello is his example. |