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14182
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If the logic of 'taller of' rests just on meaning, then logic may be the study of merely formal consequence [Read]
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Full Idea:
In 'A is taller than B, and B is taller than C, so A is taller than C' this can been seen as a matter of meaning - it is part of the meaning of 'taller' that it is transitive, but not of logic. Logic is now seen as the study of formal consequence.
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From:
Stephen Read (Formal and Material Consequence [1994], 'Reduct')
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A reaction:
I think I find this approach quite appealing. Obviously you can reason about taller-than relations, by putting the concepts together like jigsaw pieces, but I tend to think of logic as something which is necessarily implementable on a machine.
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14184
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In modus ponens the 'if-then' premise contributes nothing if the conclusion follows anyway [Read]
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Full Idea:
A puzzle about modus ponens is that the major premise is either false or unnecessary: A, If A then B / so B. If the major premise is true, then B follows from A, so the major premise is redundant. So it is false or not needed, and contributes nothing.
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From:
Stephen Read (Formal and Material Consequence [1994], 'Repres')
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A reaction:
Not sure which is the 'major premise' here, but it seems to be saying that the 'if A then B' is redundant. If I say 'it's raining so the grass is wet', it seems pointless to slip in the middle the remark that rain implies wet grass. Good point.
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14186
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Logical connectives contain no information, but just record combination relations between facts [Read]
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Full Idea:
The logical connectives are useful for bundling information, that B follows from A, or that one of A or B is true. ..They import no information of their own, but serve to record combinations of other facts.
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From:
Stephen Read (Formal and Material Consequence [1994], 'Repres')
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A reaction:
Anyone who suggests a link between logic and 'facts' gets my vote, so this sounds a promising idea. However, logical truths have a high degree of generality, which seems somehow above the 'facts'.
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8983
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If 'red' is vague, then membership of the set of red things is vague, so there is no set of red things [Sainsbury]
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Full Idea:
Sets have sharp boundaries, or are sharp objects; an object either definitely belongs to a set, or it does not. But 'red' is vague; there objects which are neither definitely red nor definitely not red. Hence there is no set of red things.
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From:
Mark Sainsbury (Concepts without Boundaries [1990], §2)
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A reaction:
Presumably that will entail that there IS a set of things which can be described as 'definitely red'. If we describe something as 'definitely having a hint of red about it', will that put it in a set? In fact will the applicability of 'definitely' do?
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8986
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We should abandon classifying by pigeon-holes, and classify around paradigms [Sainsbury]
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Full Idea:
We must reject the classical picture of classification by pigeon-holes, and think in other terms: classifying can be, and often is, clustering round paradigms.
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From:
Mark Sainsbury (Concepts without Boundaries [1990], §8)
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A reaction:
His conclusion to a discussion of the problem of vagueness, where it is identified with concepts which have no boundaries. Pigeon-holes are a nice exemplar of the Enlightenment desire to get everything right. I prefer Aristotle's categories, Idea 3311.
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8984
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If concepts are vague, people avoid boundaries, can't spot them, and don't want them [Sainsbury]
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Full Idea:
Vague concepts are boundaryless, ...and the manifestations are an unwillingness to draw any such boundaries, the impossibility of identifying such boundaries, and needlessness and even disutility of such boundaries.
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From:
Mark Sainsbury (Concepts without Boundaries [1990], §5)
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A reaction:
People have a very fine-tuned notion of whether the sharp boundary of a concept is worth discussing. The interesting exception are legal people, who are often forced to find precision where everyone else hates it. Who deserves to inherit the big house?
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8985
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Boundaryless concepts tend to come in pairs, such as child/adult, hot/cold [Sainsbury]
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Full Idea:
Boundaryless concepts tend to come in systems of contraries: opposed pairs like child/adult, hot/cold, weak/strong, true/false, and complex systems of colour terms. ..Only a contrast with 'adult' will show what 'child' excludes.
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From:
Mark Sainsbury (Concepts without Boundaries [1990], §5)
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A reaction:
This might be expected. It all comes down to the sorites problem, of when one thing turns into something else. If it won't merge into another category, then presumably the isolated concept stays applicable (until reality terminates it? End of sheep..).
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18284
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Particulars can be verified or falsified, but general statements can only be falsified (conclusively) [Popper]
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Full Idea:
Whereas particular reality statements are in principle completely verifiable or falsifiable, things are different for general reality statements: they can indeed be conclusively falsified, they can acquire a negative truth value, but not a positive one.
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From:
Karl Popper (Two Problems of Epistemology [1932], p.256), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 18 'Laws'
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A reaction:
This sounds like a logician's approach to science, but I prefer to look at coherence, where very little is actually conclusive, and one tinkers with the theory instead.
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