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All the ideas for 'Stipulation, Meaning and Apriority', 'An Enquiry' and 'Foundations of Geometry'

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12 ideas

2. Reason / D. Definition / 13. Against Definition
How do we determine which of the sentences containing a term comprise its definition? [Horwich]
     Full Idea: How are we to determine which of the sentences containing a term comprise its definition?
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §2)
     A reaction: Nice question. If I say 'philosophy is the love of wisdom' and 'philosophy bores me', why should one be part of its definition and the other not? What if I stipulated that the second one is part of my definition, and the first one isn't?
6. Mathematics / A. Nature of Mathematics / 2. Geometry
Hilbert aimed to eliminate number from geometry [Hilbert, by Hart,WD]
     Full Idea: One of Hilbert's aims in 'The Foundations of Geometry' was to eliminate number [as measure of lengths and angles] from geometry.
     From: report of David Hilbert (Foundations of Geometry [1899]) by William D. Hart - The Evolution of Logic 2
     A reaction: Presumably this would particularly have to include the elimination of ratios (rather than actual specific lengths).
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid axioms concerns possibilities of construction, but Hilbert's assert the existence of objects [Hilbert, by Chihara]
     Full Idea: Hilbert's geometrical axioms were existential in character, asserting the existence of certain geometrical objects (points and lines). Euclid's postulates do not assert the existence of anything; they assert the possibility of certain constructions.
     From: report of David Hilbert (Foundations of Geometry [1899]) by Charles Chihara - A Structural Account of Mathematics 01.1
     A reaction: Chihara says geometry was originally understood modally, but came to be understood existentially. It seems extraordinary to me that philosophers of mathematics can have become more platonist over the centuries.
Hilbert's formalisation revealed implicit congruence axioms in Euclid [Hilbert, by Horsten/Pettigrew]
     Full Idea: In his formal investigation of Euclidean geometry, Hilbert uncovered congruence axioms that implicitly played a role in Euclid's proofs but were not explicitly recognised.
     From: report of David Hilbert (Foundations of Geometry [1899]) by Horsten,L/Pettigrew,R - Mathematical Methods in Philosophy 2
     A reaction: The writers are offering this as a good example of the benefits of a precise and formal approach to foundational questions. It's hard to disagree, but dispiriting if you need a PhD in maths before you can start doing philosophy.
Hilbert's geometry is interesting because it captures Euclid without using real numbers [Hilbert, by Field,H]
     Full Idea: Hilbert's formulation of the Euclidean theory is of special interest because (besides being rigorously axiomatised) it does not employ the real numbers in the axioms.
     From: report of David Hilbert (Foundations of Geometry [1899]) by Hartry Field - Science without Numbers 3
     A reaction: Notice that this job was done by Hilbert, and not by the fictionalist Hartry Field.
12. Knowledge Sources / A. A Priori Knowledge / 1. Nature of the A Priori
A priori belief is not necessarily a priori justification, or a priori knowledge [Horwich]
     Full Idea: It is one thing to believe something a priori and another for this belief to be epistemically justified. The latter is required for a priori knowledge.
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §8)
     A reaction: Personally I would agree with this, because I don't think anything should count as knowledge if it doesn't have supporting reasons, but fans of a priori knowledge presumably think that certain basic facts are just known. They are a priori justified.
12. Knowledge Sources / A. A Priori Knowledge / 6. A Priori from Reason
Understanding needs a priori commitment [Horwich]
     Full Idea: Understanding is itself based on a priori commitment.
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §12)
     A reaction: This sounds plausible, but needs more justification than Horwich offers. This is the sort of New Rationalist idea I associate with Bonjour. The crucial feature of the New lot is, I take it, their fallibilism. All understanding is provisional.
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
Meaning is generated by a priori commitment to truth, not the other way around [Horwich]
     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.
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §8)
     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.
12. Knowledge Sources / A. A Priori Knowledge / 9. A Priori from Concepts
Meanings and concepts cannot give a priori knowledge, because they may be unacceptable [Horwich]
     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.
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §12)
     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.
If we stipulate the meaning of 'number' to make Hume's Principle true, we first need Hume's Principle [Horwich]
     Full Idea: If we stipulate the meaning of 'the number of x's' so that it makes Hume's Principle true, we must accept Hume's Principle. But a precondition for this stipulation is that Hume's Principle be accepted a priori.
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §9)
     A reaction: Yet another modern Quinean argument that all attempts at defining things are circular. I am beginning to think that the only a priori knowledge we have is of when a group of ideas is coherent. Calling it 'intuition' might be more accurate.
12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective
A priori knowledge (e.g. classical logic) may derive from the innate structure of our minds [Horwich]
     Full Idea: One potential source of a priori knowledge is the innate structure of our minds. We might, for example, have an a priori commitment to classical logic.
     From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §11)
     A reaction: Horwich points out that to be knowledge it must also say that we ought to believe it. I'm wondering whether if we divided the whole territory of the a priori up into intuitions and then coherent justifications, the whole problem would go away.
13. Knowledge Criteria / C. External Justification / 7. Testimony
We treat testimony with a natural trade off of belief and caution [Reid, by Fricker,M]
     Full Idea: Reid says we naturally operate counterpart principles of veracity and credulity in our testimonial exchanges.
     From: report of Thomas Reid (An Enquiry [1764], 6.24) by Miranda Fricker - Epistemic Injustice 1.3 n11
     A reaction: What you would expect from someone who believed in common sense. Fricker contrasts this with Tyler Burge's greater confidence, and then criticises both (with Reid too cautious and Burge over-confident). She defends a 'low-level' critical awareness.