3 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. |
21681 | Given all true atomic propositions, in theory every other truth can thereby be deduced [Russell] |
Full Idea: Given all true atomic propositions, together with the fact that they are all, every other true proposition can theoretically be deduced by logical methods. | |
From: Bertrand Russell (Intro to 2nd ed of Principia Mathematica [1925], p.xv) | |
A reaction: This is evidently his strongest statement of the ideal underlying logical atomism. The atoms were initially sense-date, but then became atomic propositions saying an object has a property. |
5845 | Niceratus learnt the whole of Homer by heart, as a guide to goodness [Xenophon] |
Full Idea: Niceratus said that his father, because he was concerned to make him a good man, made him learn the whole works of Homer, and he could still repeat by heart the entire 'Iliad' and 'Odyssey'. | |
From: Xenophon (Symposium [c.391 BCE], 3.5) | |
A reaction: This clearly shows the status which Homer had in the teaching of morality in the time of Socrates, and it is precisely this acceptance of authority which he was challenging, in his attempts to analyse the true basis of virtue |