more from this thinker     |     more from this text


Single Idea 9833

[filed under theme 18. Thought / E. Abstraction / 8. Abstractionism Critique ]

Full Idea

To get units by abstraction, units arrived at by abstraction from forks must the identical to that abstracted from spoons, with no trace of individuality. But if spoons can no longer be differentiated from forks, they can't differ from one another either.

Gist of Idea

To abstract from spoons (to get the same number as the forks), the spoons must be indistinguishable too

Source

Michael Dummett (Frege philosophy of mathematics [1991], Ch. 8)

Book Ref

Dummett,Michael: 'Frege: philosophy of mathematics' [Duckworth 1991], p.86


A Reaction

[compressed] Dummett makes the point better than Frege did. Can we 'think of a fork insofar as it is countable, ignoring its other features'? What are we left thinking of? Frege says it must still be the whole fork. 'Nice fork, apart from the colour'.


The 28 ideas with the same theme [reasons to reject the abstractionist explanation]:

If health happened to be white, the science of health would not study whiteness [Aristotle]
Abelard's problem is the purely singular aspects of things won't account for abstraction [Panaccio on Abelard]
The mind must produce by its own power an image of the individual species [Aquinas]
Thomae's idea of abstract from peculiarities gives a general concept, and leaves the peculiarities [Frege on Thomae]
Dedekind has a conception of abstraction which is not psychologistic [Dedekind, by Tait]
If we abstract the difference between two houses, they don't become the same house [Frege]
Number-abstraction somehow makes things identical without changing them! [Frege]
Frege said concepts were abstract entities, not mental entities [Frege, by Putnam]
Psychologism blunders in focusing on concept-formation instead of delineating the concepts [Dummett on Husserl]
Husserl wanted to keep a shadowy remnant of abstracted objects, to correlate them [Dummett on Husserl]
The abstractionist cannot explain 'some' and 'not' [Geach]
Only a judgement can distinguish 'striking' from 'being struck' [Geach]
'Or' and 'not' are not to be found in the sensible world, or even in the world of inner experience [Geach]
We can't acquire number-concepts by extracting the number from the things being counted [Geach]
Abstractionists can't explain counting, because it must precede experience of objects [Geach]
The numbers don't exist in nature, so they cannot have been abstracted from there into our languages [Geach]
Blind people can use colour words like 'red' perfectly intelligently [Geach]
If 'black' and 'cat' can be used in the absence of such objects, how can such usage be abstracted? [Geach]
We can form two different abstract concepts that apply to a single unified experience [Geach]
To abstract from spoons (to get the same number as the forks), the spoons must be indistinguishable too [Dummett]
To 'abstract from' is a logical process, as opposed to the old mental view [Dummett]
We can't account for an abstraction as 'from' something if the something doesn't exist [Lewis]
Abstraction cannot produce the concept of a 'game', as there is no one common feature [Barnes,J]
Abstraction from an ambiguous concept like 'mole' will define them as the same [Barnes,J]
Defining concepts by abstractions will collect together far too many attributes from entities [Barnes,J]
After abstraction all numbers seem identical, so only 0 and 1 will exist! [Fine,K]
Why should abstraction from two equipollent sets lead to the same set of 'pure units'? [Tait]
If abstraction produces power sets, their identity should imply identity of the originals [Tait]