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9390
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Logic guides thinking, but it isn't a substitute for it [Rumfitt]
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Full Idea:
Logic is part of a normative theory of thinking, not a substitute for thinking.
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From:
Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.13)
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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.
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9389
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Vague membership of sets is possible if the set is defined by its concept, not its members [Rumfitt]
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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.
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From:
Ian Rumfitt (The Logic of Boundaryless Concepts [2007], p.5)
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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.
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16672
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Quantity is the quantified parts of a thing, plus location and coordination [Olivi]
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Full Idea:
Quantity refers to nothing other than the parts of the thing quantified, together with their location or position, being extrinsically coordinated with each other.
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From:
Peter John Olivi (Treatise on Quantity [1286], f. 49vb), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 14.1
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A reaction:
I'm not sure I understand 'extrinsically'. Is there some external stretching force? God spends his time spreading out his stuff? It is nice that being spread out isn't taken for granted. We take much more for granted than they did. Motion, for example.
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