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All the ideas for 'fragments/reports', 'The philosophical basis of intuitionist logic' and 'Propositions'

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11 ideas

4. Formal Logic / E. Nonclassical Logics / 2. Intuitionist Logic
Dummett says classical logic rests on meaning as truth, while intuitionist logic rests on assertability [Dummett, by Kitcher]
     Full Idea: Dummett argues that classical logic depends on the choice of the concept of truth as central to the theory of meaning, while for the intuitionist the concept of assertability occupies this position.
     From: report of Michael Dummett (The philosophical basis of intuitionist logic [1973]) by Philip Kitcher - The Nature of Mathematical Knowledge 06.5
     A reaction: Since I can assert any nonsense I choose, this presumably means 'warranted' assertability, which is tied to the concept of proof in mathematics. You can reason about falsehoods, or about uninterpreted variables. Can you 'assert' 'Fx'?
5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive
Maybe proper names have the content of fixing a thing's category [Bealer]
     Full Idea: Some say that proper names have no descriptive content, but others think that although a name does not have the right sort of descriptive content which fixes a unique referent, it has a content which fixes the sort or category to which it belongs.
     From: George Bealer (Propositions [1998], §7)
     A reaction: Presumably 'Mary', and 'Felix', and 'Rover', and 'Smallville' are cases in point. There is a well known journalist called 'Manchester', a famous man called 'Hilary', a village in Hertfordshire called 'Matching Tie'... Interesting, though.
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions
The four leading theories of definite descriptions are Frege's, Russell's, Evans's, and Prior's [Bealer]
     Full Idea: The four leading theories of definite descriptions are Frege's, Russell's, Evans's, and Prior's, ...of which to many Frege's is the most intuitive of the four. Frege says they refer to the unique item (if it exists) which satisfies the predicate.
     From: George Bealer (Propositions [1998], §5)
     A reaction: He doesn't expound the other three, but I record this a corrective to the view that Russell has the only game in town.
5. Theory of Logic / G. Quantification / 1. Quantification
Classical quantification is an infinite conjunction or disjunction - but you may not know all the instances [Dummett]
     Full Idea: Classical quantification represents an infinite conjunction or disjunction, and the truth-value is determined by the infinite sum or product of the instances ....but this presupposes that all the instances already possess determinate truth-values.
     From: Michael Dummett (The philosophical basis of intuitionist logic [1973], p.246)
     A reaction: In the case of the universal quantifier, Dummett is doing no more than citing the classic empiricism objection to induction - that you can't make the universal claim if you don't know all the instances. The claim is still meaningful, though.
13. Knowledge Criteria / E. Relativism / 2. Knowledge as Convention
By nature people are close to one another, but culture drives them apart [Hippias]
     Full Idea: I regard you all as relatives - by nature, not by convention. By nature like is akin to like, but convention is a tyrant over humankind and often constrains people to act contrary to nature.
     From: Hippias (fragments/reports [c.430 BCE]), quoted by Plato - Protagoras 337c8
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
Stating a sentence's truth-conditions is just paraphrasing the sentence [Dummett]
     Full Idea: An ability to state the condition for the truth of a sentence is, in effect, no more than an ability to express the content of the sentence in other words.
     From: Michael Dummett (The philosophical basis of intuitionist logic [1973], p.224)
     A reaction: Alternatively, if you give something other than a paraphrase of the sentence as its meaning (such as a proof of its truth), then you seem to have departed from your target sentence. Can we reduce and eliminate our sentences in this way?
If a sentence is effectively undecidable, we can never know its truth conditions [Dummett]
     Full Idea: If a sentence is effectively undecidable, the condition which must obtain for it to be true is not one which we are capable of recognising whenever it obtains, or of getting ourselves in a position to do so.
     From: Michael Dummett (The philosophical basis of intuitionist logic [1973], p.225)
     A reaction: The instances of 'undecidable' sentences are most clearly seen in mathematics, such as the Continuum Hypothesis or Goldbach's Conjecture, or anything involving vast infinite cardinals. But do you need precise truth-conditions for meaning?
19. Language / A. Nature of Meaning / 6. Meaning as Use
Meaning as use puts use beyond criticism, and needs a holistic view of language [Dummett]
     Full Idea: If use constitutes meaning, it might seem that use is beyond criticism. ....But such an attitude can, ultimately, be supported onlly by the adoption of a holistic view of language.
     From: Michael Dummett (The philosophical basis of intuitionist logic [1973], p.218)
     A reaction: Dummett goes on to say that the rejection of the holistic view of mathematical meaning leads to his preference for intuitionistic logic.
19. Language / D. Propositions / 1. Propositions
Sentences saying the same with the same rigid designators may still express different propositions [Bealer]
     Full Idea: The propositions behind 'Cicero is emulated more than Tully' seems to differ somehow from 'Tully is emulated more than Cicero', despite the proper names being rigid designators.
     From: George Bealer (Propositions [1998], §1)
     A reaction: Interesting, because this isn't a directly propositional attitude situation like 'believes', though it depends on such things. Bealer says this is a key modern difficulty with propositions.
Propositions might be reduced to functions (worlds to truth values), or ordered sets of properties and relations [Bealer]
     Full Idea: The reductionist view of propositions sees them as either extensional functions from possible worlds to truth values, or as ordered sets of properties, relations, and perhaps particulars.
     From: George Bealer (Propositions [1998], §1)
     A reaction: The usual problem of all functional accounts is 'what is it about x that enables it to have that function?' And if they are sets, where does the ordering come in? A proposition isn't just a list of items in some particular order. Both wrong.
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
Modal logic and brain science have reaffirmed traditional belief in propositions [Bealer]
     Full Idea: Philosophers have been skeptical about abstract objects, and so have been skeptical about propositions,..but with the rise of modal logic and metaphysics, and cognitive science's realism about intentional states, traditional propositions are now dominant.
     From: George Bealer (Propositions [1998], §1)
     A reaction: I personally strongly favour belief in propositions as brain states, which don't need a bizarre ontological status, but are essential to explain language, reasoning and communication.