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Single Idea 10300

[filed under theme 5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence ]

Full Idea

Informally, logical consequence is sometimes defined in terms of the meanings of a certain collection of terms, the so-called 'logical terminology'.

Gist of Idea

Logical consequence can be defined in terms of the logical terminology

Source

Stewart Shapiro (Higher-Order Logic [2001], 2.4)

Book Ref

'Blackwell Guide to Philosophical Logic', ed/tr. Goble,Lou [Blackwell 2001], p.51


A Reaction

This seems to be a compositional account, where we build a full account from an account of the atomic bits, perhaps presented as truth-tables.


The 12 ideas from 'Higher-Order Logic'

First-order logic is Complete, and Compact, with the Löwenheim-Skolem Theorems [Shapiro]
Second-order variables also range over properties, sets, relations or functions [Shapiro]
Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro]
Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro]
Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro]
Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro]
The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro]
The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro]
Some say that second-order logic is mathematics, not logic [Shapiro]
If the aim of logic is to codify inferences, second-order logic is useless [Shapiro]
Logical consequence can be defined in terms of the logical terminology [Shapiro]
The axiom of choice is controversial, but it could be replaced [Shapiro]