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Single Idea 10015

[filed under theme 5. Theory of Logic / A. Overview of Logic / 7. Second-Order Logic ]

Full Idea

Brand higher-order logic as unintelligible if you will, but don't conflate it with set theory.

Gist of Idea

Higher-order logic may be unintelligible, but it isn't set theory

Source

Harold Hodes (Logicism and Ontological Commits. of Arithmetic [1984], p.131)

Book Ref

-: 'Journal of Philosophy' [-], p.131


A Reaction

[he gives Boolos 1975 as a further reference] This is simply a corrective, because the conflation of second-order logic with set theory is an idea floating around in the literature.


The 10 ideas from 'Logicism and Ontological Commits. of Arithmetic'

Identity is a level one relation with a second-order definition [Hodes]
Mathematics is higher-order modal logic [Hodes]
It is claimed that numbers are objects which essentially represent cardinality quantifiers [Hodes]
When an 'interpretation' creates a model based on truth, this doesn't include Fregean 'sense' [Hodes]
Truth in a model is more tractable than the general notion of truth [Hodes]
Higher-order logic may be unintelligible, but it isn't set theory [Hodes]
Truth is quite different in interpreted set theory and in the skeleton of its language [Hodes]
Numerical terms can't really stand for quantifiers, because that would make them first-level [Hodes]
Talk of mirror images is 'encoded fictions' about real facts [Hodes]
Arithmetic must allow for the possibility of only a finite total of objects [Hodes]