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7. Existence / C. Structure of Existence / 7. Abstract/Concrete / b. Levels of abstraction

[possible degrees or levels of abstraction]

6 ideas
10502 We can rise by degrees through abstraction, with higher levels representing more things [Arnauld,A/Nicole,P]
     Full Idea: I can start with a triangle, and rise by degrees to all straight-lined figures and to extension itself. The lower degree will include the higher degree. Since the higher degree is less determinate, it can represent more things.
     From: Arnauld / Nicole (Logic (Port-Royal Art of Thinking) [1662], I.5)
     A reaction: [compressed] This attempts to explain the generalising ability of abstraction cited in Idea 10501. If you take a complex object and eliminate features one by one, it can only 'represent' more particulars; it could hardly represent fewer.
9578 If objects are just presentation, we get increasing abstraction by ignoring their properties [Frege]
     Full Idea: If an object is just presentation, we can pay less attention to a property and it disappears. By letting one characteristic after another disappear, we obtain concepts that are increasingly more abstract.
     From: Gottlob Frege (Review of Husserl's 'Phil of Arithmetic' [1894], p.324)
     A reaction: Frege despises this view. Note there is scope in the despised view for degrees or levels of abstraction, defined in terms of number of properties ignored. Part of Frege's criticism is realist. He retains the object, while Husserl imagines it different.
10563 A generative conception of abstracts proposes stages, based on concepts of previous objects [Fine,K]
     Full Idea: It is natural to have a generative conception of abstracts (like the iterative conception of sets). The abstracts are formed at stages, with the abstracts formed at any given stage being the abstracts of those concepts of objects formed at prior stages.
     From: Kit Fine (Replies on 'Limits of Abstraction' [2005], 1)
     A reaction: See 10567 for Fine's later modification. This may not guarantee 'levels', but it implies some sort of conceptual priority between abstract entities.
9927 Mathematics has ascended to higher and higher levels of abstraction [Burgess/Rosen]
     Full Idea: In mathematics, since the beginning of the nineteenth century, there has been an ascent to higher and higher levels of abstraction.
     From: JP Burgess / G Rosen (A Subject with No Object [1997], II.C.1.b)
     A reaction: I am interested in clarifying what this means, which might involve the common sense and psychological view of the matter, as well as some sort of formal definition in terms of equivalence (or whatever).
9930 Abstraction is on a scale, of sets, to attributes, to type-formulas, to token-formulas [Burgess/Rosen]
     Full Idea: There is a scale of abstractness that leads downwards from sets through attributes to formulas as abstract types and on to formulas as abstract tokens.
     From: JP Burgess / G Rosen (A Subject with No Object [1997], III.B.2.c)
     A reaction: Presumably the 'abstract tokens' at the bottom must have some interpretation, to support the system. Presumably one can keep going upwards, through sets of sets of sets.
10524 There is a hierarchy of abstraction, based on steps taken by equivalence relations [Hale]
     Full Idea: The domain of the abstract can be seen as exemplifying a hierarchical structure, with differences of level reflecting the number of steps of abstraction, via appropriate equivalence relations, required for recognition at different levels.
     From: Bob Hale (Abstract Objects [1987], Ch.3.III)
     A reaction: I think this is right, and so does almost everyone else, since people cheerfully talk of 'somewhat' abstract and 'highly' abstract. Don't dream of a neat picture though. You might reach a level by two steps from one direction, and four from another.