Combining Texts

All the ideas for 'The Logic of Boundaryless Concepts', 'Natural Science (lost)' and 'Predest.,God's foreknowledge and contingents'

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4 ideas

5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
9390 Logic guides thinking, but it isn't a substitute for it [Rumfitt]
     Full Idea: Logic is part of a normative theory of thinking, not a substitute for thinking.
     From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.13)
     A reaction: There is some sort of logicians' dream, going back to Leibniz, of a reasoning engine, which accepts propositions and outputs inferences. I agree with this idea. People who excel at logic are often, it seems to me, modest at philosophy.
7. Existence / A. Nature of Existence / 6. Criterion for Existence
527 Everything exists which anyone perceives [Metrodorus of Chios]
     Full Idea: Everything exists which anyone perceives.
     From: Metrodorus (Chi) (Natural Science (lost) [c.340 BCE], B2), quoted by (who?) - where?
     A reaction: cf Berkeley and Epicurus. This misses out the problem of perceptual error, such as a square tower looking round from a distance, or one person in a group thinking they have seen something. It is still a good criterion, though!
7. Existence / E. Categories / 5. Category Anti-Realism
16654 Our words and concepts don't always correspond to what is out there [William of Ockham]
     Full Idea: It should not be said that as distinct words and intentions or concepts are distinct from one another, so too the corresponding things are distinct. Those distinctions do not always line up with distinctions among things that are signified.
     From: William of Ockham (Predest.,God's foreknowledge and contingents [1320], 7.1), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 12.2
     A reaction: [compressed] This is the great nominalist opponent of the idea that Aristotle's ten categories give an accurate map of reality. He proposed just substance and accidents, and based categorisation on the questions we ask.
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
9389 Vague membership of sets is possible if the set is defined by its concept, not its members [Rumfitt]
     Full Idea: Vagueness in respect of membership is consistency with determinacy of the set's identity, so long as a set's identity is taken to consist, not in its having such-and-such members, but in its being the extension of a concept.
     From: Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.5)
     A reaction: I find this view of sets much more appealing than the one that identifies a set with its members. The empty set is less of a problem, as well as non-existents. Logicians prefer the extensional view because it is tidy.