4 ideas
| 6408 | Russell needed three extra axioms to reduce maths to logic: infinity, choice and reducibility [Grayling] |
| Full Idea: In order to deduce the theorems of mathematics from purely logical axioms, Russell had to add three new axioms to those of standards logic, which were: the axiom of infinity, the axiom of choice, and the axiom of reducibility. | |
| From: A.C. Grayling (Russell [1996], Ch.2) | |
| A reaction: The third one was adopted to avoid his 'barber' paradox, but many thinkers do not accept it. The interesting question is why anyone would 'accept' or 'reject' an axiom. |
| 6414 | Two propositions might seem self-evident, but contradict one another [Grayling] |
| Full Idea: Two propositions might contradict each other despite appearing self-evident when considered separately. | |
| From: A.C. Grayling (Russell [1996], Ch.2) | |
| A reaction: Russell's proposal (Idea 5416) is important here, that self-evidence comes in degrees. If self-evidence was all-or-nothing, Grayling's point would be a major problem, but it isn't. Bonjour explores the idea more fully (e.g. Idea 3704) |
| 3214 | The models we use in reasoning may be more like perceptions than like language [Johnson-Laird] |
| Full Idea: The models that people use to reason are more likely to resemble perception or conception of the events (from a God's-eye view) than a string of symbols directly corresponding to the linguistic form of the premises and then applying rules of inference. | |
| From: P. Johnson-Laird (Mental Models [1983], p.53), quoted by Georges Rey - Contemporary Philosophy of Mind 10.1.2 | |
| A reaction: My intuition is that imagination is the single most important faculty in any conscious mind, and that even small animals have an inkling of the God's-eye view. Decisions need 'what-if' scenarios. |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| Full Idea: In singing and playing the lyre, a boy will be likely to reveal not only courage and moderation, but also justice. | |
| From: Damon (fragments/reports [c.460 BCE], B4), quoted by (who?) - where? |