Combining Texts

Ideas for 'The Middle Works (15 vols, ed Boydston)', 'What is Knowledge-First Epistemology?' and 'Logic in Mathematics'

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5 ideas

19. Language / A. Nature of Meaning / 6. Meaning as Use
A sign won't gain sense just from being used in sentences with familiar components [Frege]
     Full Idea: No sense accrues to a sign by the mere fact that it is used in one or more sentences, the other constituents of which are known.
     From: Gottlob Frege (Logic in Mathematics [1914], p.213)
     A reaction: Music to my ears. I've never grasped how meaning could be grasped entirely through use.
19. Language / C. Assigning Meanings / 2. Semantics
Entailment is modelled in formal semantics as set inclusion (where 'mammals' contains 'cats') [Dougherty/Rysiew]
     Full Idea: Entailment is modelled in formal semantics as set inclusion. 'Cat' entails 'mammal' because the cats are a subset of the mammals.
     From: Dougherty,T/Rysiew,P (What is Knowledge-First Epistemology? [2014], p.10)
     A reaction: I would have thought that this was only one type of entailment. 'Travelling to Iceland entails flying'. Travelling includes flying, the reverse of cats/mammals, to a very complex set-theoretic account is needed. Interesting.
19. Language / D. Propositions / 2. Abstract Propositions / a. Propositions as sense
Thoughts are not subjective or psychological, because some thoughts are the same for us all [Frege]
     Full Idea: A thought is not something subjective, is not the product of any form of mental activity; for the thought that we have in Pythagoras's theorem is the same for everybody.
     From: Gottlob Frege (Logic in Mathematics [1914], p.206)
     A reaction: When such thoughts are treated as if the have objective (platonic) existence, I become bewildered. I take a thought (or proposition) to be entirely psychological, but that doesn't stop two people from having the same thought.
A thought is the sense expressed by a sentence, and is what we prove [Frege]
     Full Idea: The sentence is of value to us because of the sense that we grasp in it, which is recognisably the same in a translation. I call this sense the thought. What we prove is not a sentence, but a thought.
     From: Gottlob Frege (Logic in Mathematics [1914], p.206)
     A reaction: The 'sense' is presumably the German 'sinn', and a 'thought' in Frege is what we normally call a 'proposition'. So the sense of a sentence is a proposition, and logic proves propositions. I'm happy with that.
19. Language / D. Propositions / 5. Unity of Propositions
The parts of a thought map onto the parts of a sentence [Frege]
     Full Idea: A sentence is generally a complex sign, so the thought expressed by it is complex too: in fact it is put together in such a way that parts of a thought correspond to parts of the sentence.
     From: Gottlob Frege (Logic in Mathematics [1914], p.207)
     A reaction: This is the compositional view of propositions, as opposed to the holistic view.