16030
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'Nominal' definitions identify things, but fail to give their essence [Jones,J-E]
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Full Idea:
In the Aristotelian tradition, a 'nominal' definition is a pseudo-definition that identifies the members of the species or genus, but fails to capture the essence, e.g. 'man is the featherless biped'.
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From:
Jan-Erik Jones (Real Essence [2012], §2)
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A reaction:
You can 'individuate' an object as 'the only object in that drawer', while revealing nothing about it. So what must a definition do, in addition to picking something out uniquely?
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13342
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Carnap defined consequence by contradiction, but this is unintuitive and changes with substitution [Tarski on Carnap]
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Full Idea:
Carnap proposed to define consequence as 'sentence X follows from the sentences K iff the sentences K and the negation of X are contradictory', but 1) this is intuitively impossible, and 2) consequence would be changed by substituting objects.
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From:
comment on Rudolph Carnap (The Logical Syntax of Language [1934], p.88-) by Alfred Tarski - The Concept of Logical Consequence p.414
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A reaction:
This seems to be the first step in the ongoing explicit discussion of the nature of logical consequence, which is now seen by many as the central concept of logic. Tarski brings his new tool of 'satisfaction' to bear.
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13251
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Each person is free to build their own logic, just by specifying a syntax [Carnap]
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Full Idea:
In logic, there are no morals. Everyone is at liberty to build his own logic, i.e. his own form of language. All that is required is that he must state his methods clearly, and give syntactical rules instead of philosophical arguments.
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From:
Rudolph Carnap (The Logical Syntax of Language [1934], §17), quoted by JC Beall / G Restall - Logical Pluralism 7.3
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A reaction:
This is understandable, but strikes me as close to daft relativism. If I specify a silly logic, I presume its silliness will be obvious. By what criteria? I say the world dictates the true logic, but this is a minority view.
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9332
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Meaning is generated by a priori commitment to truth, not the other way around [Horwich]
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Full Idea:
Our a priori commitment to certain sentences is not really explained by our knowledge of a word's meaning. It is the other way around. We accept a priori that the sentences are true, and thereby provide it with meaning.
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From:
Paul Horwich (Stipulation, Meaning and Apriority [2000], §8)
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A reaction:
This sounds like a lovely trump card, but how on earth do you decide that a sentence is true if you don't know what it means? Personally I would take it that we are committed to the truth of a proposition, before we have a sentence for it.
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9341
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Meanings and concepts cannot give a priori knowledge, because they may be unacceptable [Horwich]
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Full Idea:
A priori knowledge of logic and mathematics cannot derive from meanings or concepts, because someone may possess such concepts, and yet disagree with us about them.
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From:
Paul Horwich (Stipulation, Meaning and Apriority [2000], §12)
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A reaction:
A good argument. The thing to focus on is not whether such ideas are a priori, but whether they are knowledge. I think we should employ the word 'intuition' for a priori candidates for knowledge, and demand further justification for actual knowledge.
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