more on this theme     |     more from this thinker


Single Idea 10704

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

Full Idea

In second-order logic only the formation rules are completely formalizable, not the inference rules.

Gist of Idea

We can formalize second-order formation rules, but not inference rules

Source

Michael Potter (Set Theory and Its Philosophy [2004], 01.2)

Book Ref

Potter,Michael: 'Set Theory and Its Philosophy' [OUP 2004], p.13


A Reaction

He cites Gödel's First Incompleteness theorem for this.


The 14 ideas from 'Set Theory and Its Philosophy'

Set theory's three roles: taming the infinite, subject-matter of mathematics, and modes of reasoning [Potter]
Supposing axioms (rather than accepting them) give truths, but they are conditional [Potter]
We can formalize second-order formation rules, but not inference rules [Potter]
Collections have fixed members, but fusions can be carved in innumerable ways [Potter]
Mereology elides the distinction between the cards in a pack and the suits [Potter]
Nowadays we derive our conception of collections from the dependence between them [Potter]
If dependence is well-founded, with no infinite backward chains, this implies substances [Potter]
Priority is a modality, arising from collections and members [Potter]
If set theory didn't found mathematics, it is still needed to count infinite sets [Potter]
Usually the only reason given for accepting the empty set is convenience [Potter]
A relation is a set consisting entirely of ordered pairs [Potter]
Infinity: There is at least one limit level [Potter]
It is remarkable that all natural number arithmetic derives from just the Peano Axioms [Potter]
The 'limitation of size' principles say whether properties collectivise depends on the number of objects [Potter]