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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21349
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Two people are indirectly related by height; the direct relation is internal, between properties [Heil]
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Full Idea:
If Simmias is taller than Socrates, they are indirectly related; they are related via their possession of properties that are themselves directly - and internally - related. Hence relational truths are made true by non-relational features of the world.
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From:
John Heil (Relations [2009], 'Founding')
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A reaction:
This seems to be a strategy for reducing external relations to internal relations, which are intrinsic to objects, which thus reduces the ontology. Heil is not endorsing it, but cites Kit Fine 2000. The germ of this idea is in Plato.
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21351
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Truthmaking is a clear example of an internal relation [Heil]
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Full Idea:
Truthmaking is a paradigmatic internal relation: if you have a truthbearer, a representation, and you have the world as the truthbearer represents it as being, you have truthmaking, you have the truthbearer's being true.
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From:
John Heil (Relations [2009], 'Causal')
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A reaction:
It is nice to have an example of an internal relation other than numbers, and closer to the concrete world. Is the relation between the world and facts about the world the same thing, or another example?
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21344
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If R internally relates a and b, and you have a and b, you thereby have R [Heil]
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Full Idea:
A simple way to think about internal relations is: if R internally relates a and b, then, if you have a and b, you thereby have R. If you have six and you have five, you thereby have six's being greater than five.
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From:
John Heil (Relations [2009], 'External')
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A reaction:
This seems to work a lot better for abstracta than for physical objects, where I am struggling to think of a parallel example. Parenthood? Temporal relations between things? Acorn and oak?
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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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