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Single Idea 10702

[filed under theme 4. Formal Logic / F. Set Theory ST / 1. Set Theory ]

Full Idea

Set theory has three roles: as a means of taming the infinite, as a supplier of the subject-matter of mathematics, and as a source of its modes of reasoning.

Gist of Idea

Set theory's three roles: taming the infinite, subject-matter of mathematics, and modes of reasoning

Source

Michael Potter (Set Theory and Its Philosophy [2004], Intro 1)

Book Ref

Potter,Michael: 'Set Theory and Its Philosophy' [OUP 2004], p.4


A Reaction

These all seem to be connected with mathematics, but there is also ontological interest in set theory. Potter emphasises that his second role does not entail a commitment to sets 'being' numbers.


The 31 ideas from Michael Potter

Traditionally there are twelve categories of judgement, in groups of three [Potter]
Frege's sign |--- meant judgements, but the modern |- turnstile means inference, with intecedents [Potter]
A material conditional cannot capture counterfactual reasoning [Potter]
Compositionality should rely on the parsing tree, which may contain more than sentence components [Potter]
'Direct compositonality' says the components wholly explain a sentence meaning [Potter]
'Greater than', which is the ancestral of 'successor', strictly orders the natural numbers [Potter]
Impredicative definitions are circular, but fine for picking out, rather than creating something [Potter]
Deductivism can't explain how the world supports unconditional conclusions [Potter]
If 'concrete' is the negative of 'abstract', that means desires and hallucinations are concrete [Potter]
The phrase 'the concept "horse"' can't refer to a concept, because it is saturated [Potter]
Modern logical truths are true under all interpretations of the non-logical words [Potter]
Compositionality is more welcome in logic than in linguistics (which is more contextual) [Potter]
Why is fictional arithmetic applicable to the real world? [Potter]
The Identity Theory says a proposition is true if it coincides with what makes it true [Potter]
The formalist defence against Gödel is to reject his metalinguistic concept of truth [Potter]
It has been unfortunate that externalism about truth is equated with correspondence [Potter]
Knowledge from a drunken schoolteacher is from a reliable and unreliable process [Potter]
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]
Mereology elides the distinction between the cards in a pack and the suits [Potter]
Collections have fixed members, but fusions can be carved in innumerable ways [Potter]
Nowadays we derive our conception of collections from the dependence between them [Potter]
Priority is a modality, arising from collections and members [Potter]
If dependence is well-founded, with no infinite backward chains, this implies substances [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]