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Single Idea 9926

[filed under theme 5. Theory of Logic / E. Structures of Logic / 6. Relations in Logic ]

Full Idea

While in general a relation is taken to be a set of ordered pairs <u, v> = {{u}, {u, v}}, and hence a set of sets of sets, in special cases a relation can be represented by a set of sets.

Gist of Idea

A relation is either a set of sets of sets, or a set of sets

Source

JP Burgess / G Rosen (A Subject with No Object [1997], II.C.1.a)

Book Ref

Burgess,J/Rosen,G: 'A Subject with No Object' [OUP 1997], p.150


A Reaction

[See book for their examples, which are <, symmetric, and arbitrary] The fact that a relation (or anything else) can be represented in a certain way should never ever be taken to mean that you now know what the thing IS.


The 11 ideas with the same theme [role of terms which connect objects into relationships]:

De Morgan found inferences involving relations, which eluded Aristotle's syllogistic [De Morgan, by Hart,WD]
De Morgan started the study of relations and their properties [De Morgan, by Walicki]
The logic of relatives relies on objects built of any relations (rather than on classes) [Peirce]
Relations are functions with two arguments [Frege]
In 'Principia' a new abstract theory of relations appeared, and was applied [Russell/Whitehead, by Gödel]
All relations, apart from ancestrals, can be reduced to simpler logic [Quine]
We can use mereology to simulate quantification over relations [Lewis]
Relations need terms, so they must be second-order entities based on first-order tropes [Campbell,K]
A relation is either a set of sets of sets, or a set of sets [Burgess/Rosen]
The mathematics of relations is entirely covered by ordered pairs [Chihara]
'Before' and 'after' are not two relations, but one relation with two orders [Hossack]