display all the ideas for this combination of philosophers
5 ideas
10624 | The incompletability of formal arithmetic reveals that logic also cannot be completely characterized [Hale/Wright] |
Full Idea: The incompletability of formal arithmetic reveals, not arithmetical truths which are not truths of logic, but that logical truth likewise defies complete deductive characterization. ...Gödel's result has no specific bearing on the logicist project. | |
From: B Hale / C Wright (Intro to 'The Reason's Proper Study' [2001], §2 n5) | |
A reaction: This is the key defence against the claim that Gödel's First Theorem demolished logicism. |
8784 | Neo-logicism founds arithmetic on Hume's Principle along with second-order logic [Hale/Wright] |
Full Idea: The result of joining Hume's Principle to second-order logic is a consistent system which is a foundation for arithmetic, in the sense that all the fundamental laws of arithmetic are derivable within it as theorems. This seems a vindication of logicism. | |
From: B Hale / C Wright (Logicism in the 21st Century [2007], 1) | |
A reaction: The controversial part seems to be second-order logic, which Quine (for example) vigorously challenged. The contention against most attempts to improve Frege's logicism is that they thereby cease to be properly logical. |
8787 | The Julius Caesar problem asks for a criterion for the concept of a 'number' [Hale/Wright] |
Full Idea: The Julius Caesar problem is the problem of supplying a criterion of application for 'number', and thereby setting it up as the concept of a genuine sort of object. (Why is Julius Caesar not a number?) | |
From: B Hale / C Wright (Logicism in the 21st Century [2007], 3) | |
A reaction: One response would be to deny that numbers are objects. Another would be to derive numbers from their application in counting objects, rather than the other way round. I suspect that the problem only real bothers platonists. Serves them right. |
10629 | If structures are relative, this undermines truth-value and objectivity [Hale/Wright] |
Full Idea: The relativization of ontology to theory in structuralism can't avoid carrying with it a relativization of truth-value, which would compromise the objectivity which structuralists wish to claim for mathematics. | |
From: B Hale / C Wright (Intro to 'The Reason's Proper Study' [2001], 3.2 n26) | |
A reaction: This is the attraction of structures which grow out of the physical world, where truth-value is presumably not in dispute. |
10628 | The structural view of numbers doesn't fit their usage outside arithmetical contexts [Hale/Wright] |
Full Idea: It is not clear how the view that natural numbers are purely intra-structural 'objects' can be squared with the widespread use of numerals outside purely arithmetical contexts. | |
From: B Hale / C Wright (Intro to 'The Reason's Proper Study' [2001], 3.2 n26) | |
A reaction: I don't understand this objection. If they refer to quantity, they are implicitly cardinal. If they name things in a sequence they are implicitly ordinal. All users of numbers have a grasp of the basic structure. |