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Single Idea 13041

[filed under theme 9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts ]

Full Idea

A collection has a determinate number of members, whereas a fusion may be carved up into parts in various equally valid (although perhaps not equally interesting) ways.

Gist of Idea

Collections have fixed members, but fusions can be carved in innumerable ways

Source

Michael Potter (Set Theory and Its Philosophy [2004], 02.1)

Book Ref

Potter,Michael: 'Set Theory and Its Philosophy' [OUP 2004], p.22


A Reaction

This seems to sum up both the attraction and the weakness of mereology. If you doubt the natural identity of so-called 'objects', then maybe classical mereology is the way to go.


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]