Combining Texts

All the ideas for 'Abstract Objects: a Case Study', 'Philosophy of Logics' and 'On the Principles of Indiscernibles'

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7 ideas

3. Truth / C. Correspondence Truth / 3. Correspondence Truth critique
Logical truth seems much less likely to 'correspond to the facts' than factual truth does [Haack]
     Full Idea: It is surely less plausible to suppose that logical truth consists in correspondence to the facts than that 'factual' truth does.
     From: Susan Haack (Philosophy of Logics [1978], 7.6)
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
The same sentence could be true in one language and meaningless in another, so truth is language-relative [Haack]
     Full Idea: The definition of truth will have to be, Tarski argues, relative to a language, for one and the same sentence may be true in one language, and false or meaningless in another.
     From: Susan Haack (Philosophy of Logics [1978], 7.5)
6. Mathematics / C. Sources of Mathematics / 6. Logicism / c. Neo-logicism
Mathematics is both necessary and a priori because it really consists of logical truths [Yablo]
     Full Idea: Mathematics seems necessary because the real contents of mathematical statements are logical truths, which are necessary, and it seems a priori because logical truths really are a priori.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 10)
     A reaction: Yablo says his logicism has a Kantian strain, because numbers and sets 'inscribed on our spectacles', but he takes a different view (in the present Idea) from Kant about where the necessity resides. Personally I am tempted by an a posteriori necessity.
6. Mathematics / C. Sources of Mathematics / 9. Fictional Mathematics
Putting numbers in quantifiable position (rather than many quantifiers) makes expression easier [Yablo]
     Full Idea: Saying 'the number of Fs is 5', instead of using five quantifiers, puts the numeral in quantifiable position, which brings expressive advantages. 'There are more sheep in the field than cows' is an infinite disjunction, expressible in finite compass.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 08)
     A reaction: See Hofweber with similar thoughts. This idea I take to be a key one in explaining many metaphysical confusions. The human mind just has a strong tendency to objectify properties, relations, qualities, categories etc. - for expression and for reasoning.
7. Existence / C. Structure of Existence / 7. Abstract/Concrete / a. Abstract/concrete
Concrete objects have few essential properties, but properties of abstractions are mostly essential [Yablo]
     Full Idea: Objects like me have a few essential properties, and numerous accidental ones. Abstract objects are a different story. The intrinsic properties of the empty set are mostly essential. The relations of numbers are also mostly essential.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 01)
We are thought to know concreta a posteriori, and many abstracta a priori [Yablo]
     Full Idea: Our knowledge of concreta is a posteriori, but our knowledge of numbers, at least, has often been considered a priori.
     From: Stephen Yablo (Abstract Objects: a Case Study [2002], 02)
28. God / B. Proving God / 2. Proofs of Reason / a. Ontological Proof
The concept of an existing thing must contain more than the concept of a non-existing thing [Leibniz]
     Full Idea: There must be more in the concept of a thing which exists than in that of one which does not exist.
     From: Gottfried Leibniz (On the Principles of Indiscernibles [1696], p.134)