6 ideas
17751 | Gödel proved the completeness of first order predicate logic in 1930 [Gödel, by Walicki] |
Full Idea: Gödel proved the completeness of first order predicate logic in his doctoral dissertation of 1930. | |
From: report of Kurt Gödel (Completeness of Axioms of Logic [1930]) by Michal Walicki - Introduction to Mathematical Logic History E.2.2 |
579 | Cratylus said you couldn't even step into the same river once [Cratylus, by Aristotle] |
Full Idea: Cratylus was appalled that Heraclitus said you could not step twice into the same river, because it was already going too far to admit stepping into the same river once. | |
From: report of Cratylus (fragments/reports [c.425 BCE]) by Aristotle - Metaphysics 1010a | |
A reaction: Compare Idea 427. |
6455 | Maybe 'sense-data' just help us to talk about unusual perceptual situations [Lacey] |
Full Idea: One possibility is that talk of sense-data is a mere linguistic convenience, providing a noun for talking about appearances, as when seeing a red object in sodium light (when it looks grey). | |
From: A.R. Lacey (A Dictionary of Philosophy [1976], p.196) | |
A reaction: The term seems to have been coined to deal with situations where there is a gap between appearance and presumed reality, as in illusions. Maybe illusions prove the existence of sense-data, rather than it being a 'convenient' term. |
6453 | Some claim sense-data are public, and are parts of objects [Lacey] |
Full Idea: Sometimes it is said that sense-data are public, and parts either of objects or of the surfaces of objects. | |
From: A.R. Lacey (A Dictionary of Philosophy [1976], p.196) | |
A reaction: This suggests two drastically different theories, one making sense-data into mental events, the other placing them in the 'external' world. The latter theory can dovetail them with the physics, but then why would we need them? |
6454 | Where do sense-data begin or end? Can they change? What sort of thing are they? [Lacey] |
Full Idea: It is hard to individuate sense-data, saying where one ends and the next begins, and hard to say whether they can change; are they substances, qualities, events, or what? | |
From: A.R. Lacey (A Dictionary of Philosophy [1976], p.196) | |
A reaction: The problem is not that these questions are unanswerable. The answer seems to be either that they are physical and external, or that they are mental and internal, and that there is no ontological space for them between the two. |
578 | Cratylus decided speech was hopeless, and his only expression was the movement of a finger [Cratylus, by Aristotle] |
Full Idea: Cratylus thought speech of any kind was radically inappropriate and that expression should be restricted exclusively to the movement of the finger. | |
From: report of Cratylus (fragments/reports [c.425 BCE]) by Aristotle - Metaphysics 1010a |