Combining Texts

All the ideas for 'Through the Looking Glass', 'Possible Worlds' and 'On the Foundations of Logic and Arithmetic'

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6 ideas

6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / c. Against mathematical empiricism
The existence of an arbitrarily large number refutes the idea that numbers come from experience [Hilbert]
     Full Idea: The standpoint of pure experience seems to me to be refuted by the objection that the existence, possible or actual, of an arbitrarily large number can never be derived through experience, that is, through experiment.
     From: David Hilbert (On the Foundations of Logic and Arithmetic [1904], p.130)
     A reaction: Alternatively, empiricism refutes infinite numbers! No modern mathematician will accept that, but you wonder in what sense the proposed entities qualify as 'numbers'.
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Logic already contains some arithmetic, so the two must be developed together [Hilbert]
     Full Idea: In the traditional exposition of the laws of logic certain fundamental arithmetic notions are already used, for example in the notion of set, and to some extent also of number. Thus we turn in a circle, and a partly simultaneous development is required.
     From: David Hilbert (On the Foundations of Logic and Arithmetic [1904], p.131)
     A reaction: If the Axiom of Infinity is meant, it may be possible to purge the arithmetic from the logic. Then the challenge to derive arithmetic from it becomes rather tougher.
7. Existence / A. Nature of Existence / 2. Types of Existence
Lewis's distinction of 'existing' from 'being actual' is Meinong's between 'existing' and 'subsisting' [Lycan on Lewis]
     Full Idea: I suggest that Lewis's view in fact is just Meinong's view. ...Meinong distinguishes between 'existing' and merely 'subsisting', Lewis between 'being actual' and merely 'existing'.
     From: comment on David Lewis (Possible Worlds [1973]) by William Lycan - The Trouble with Possible Worlds 06
     A reaction: Lewis attempts to make actuality purely 'indexical' in character, like distinguishing the world 'here' from the world 'elsewhere', but Lycan seems right that he is committed to more than that.
7. Existence / A. Nature of Existence / 3. Being / e. Being and nothing
I only wish I had such eyes as to see Nobody! It's as much as I can do to see real people. [Carroll,L]
     Full Idea: "I see nobody on the road," said Alice. - "I only wish I had such eyes," the King remarked. ..."To be able to see Nobody! ...Why, it's as much as I can do to see real people."
     From: Lewis Carroll (C.Dodgson) (Through the Looking Glass [1886], p.189), quoted by A.W. Moore - The Evolution of Modern Metaphysics 07.7
     A reaction: [Moore quotes this, inevitably, in a chapter on Hegel] This may be a better candidate for the birth of philosophy of language than Frege's Groundwork.
10. Modality / E. Possible worlds / 1. Possible Worlds / d. Possible worlds actualism
Lewis can't know possible worlds without first knowing what is possible or impossible [Lycan on Lewis]
     Full Idea: Lewis's knowledge of what possible worlds there are and of other general truths about worlds is posterior, not prior, to his knowledge of what things are possible and what things are impossible.
     From: comment on David Lewis (Possible Worlds [1973]) by William Lycan - The Trouble with Possible Worlds 07
     A reaction: This elementary objection seems to me to destroy any attempt to explain modality in terms of possible worlds. It is a semantics for modal statements, but that doesn't make it an ontology. To assess possibilities, study actuality.
What are the ontological grounds for grouping possibilia into worlds? [Lycan on Lewis]
     Full Idea: Lewis must seek some ontological ground for the grouping of possibilia into disjoint worlds.
     From: comment on David Lewis (Possible Worlds [1973]) by William Lycan - The Trouble with Possible Worlds 07
     A reaction: I do love people like Lycan who ask the simple commonsense questions about these highly sophisticated systems that students of philosophy are required to study. If a proposition is a 'set of worlds', understanding a proposition is beyond me.