Single Idea 18883

[catalogued under 18. Thought / E. Abstraction / 7. Abstracta by Equivalence]

Full Idea

Whenever we have an equivalence relation among things - such as similarity in a certain respect - we can abstract under the equivalence and consider the abstractum.

Gist of Idea

Any equivalence relation among similar things allows the creation of an abstractum

Source

Peter Simons (Modes of Extension: comment on Fine [2008], p.19)

Book Reference

'Being: Developments in Contemporary Metaphysics', ed/tr. Le Poidevin,R [CUP 2008], p.19


A Reaction

This strikes me as dressing up old-fashioned psychological abstractionism in the respectable clothing of Fregean equivalences (such as 'directions'). We can actually do what Simons wants without the precision of partitioned equivalence classes.

Related Idea

Idea 18884 Abstraction is usually seen as producing universals and numbers, but it can do more [Simons]