more on this theme     |     more from this text

Single Idea 13898

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

Full Idea

The fact that it seems possible to establish a sortal notion of direction by reference to lines and parallelism, discloses tacit commitments to directions in statements about parallelism...There is incoherence in the idea that a line might lack direction.

Gist of Idea

If we can establish directions from lines and parallelism, we were already committed to directions

Source

Crispin Wright (Frege's Concept of Numbers as Objects [1983], 4.xviii)

Book Ref

Wright,Crispin: 'Frege's Conception of Numbers' [Scots Philosophical Monographs 1983], p.148

A Reaction

This seems like a slippery slope into a very extravagant platonism about concepts. Are concepts like direction as much a part of the natural world as rivers are? What other undiscovered concepts await us?

The 38 ideas from Crispin Wright

10142 The attempt to define numbers by contextual definition has been revived [Wright,C, by Fine,K]
9868 An expression refers if it is a singular term in some true sentences [Wright,C, by Dummett]
7804 Wright has revived Frege's discredited logicism [Wright,C, by Benardete,JA]
17441 Wright thinks Hume's Principle is more fundamental to cardinals than the Peano Axioms are [Wright,C, by Heck]
10140 We derive Hume's Law from Law V, then discard the latter in deriving arithmetic [Wright,C, by Fine,K]
8692 Frege has a good system if his 'number principle' replaces his basic law V [Wright,C, by Friend]
17440 Wright says Hume's Principle is analytic of cardinal numbers, like a definition [Wright,C, by Heck]
9878 Contextually defined abstract terms genuinely refer to objects [Wright,C, by Dummett]
13863 Logicism seemed to fail by Russell's paradox, Gödel's theorems, and non-logical axioms [Wright,C]
13862 There are five Peano axioms, which can be expressed informally [Wright,C]
17853 Number truths are said to be the consequence of PA - but it needs semantic consequence [Wright,C]
17854 What facts underpin the truths of the Peano axioms? [Wright,C]
13861 Number theory aims at the essence of natural numbers, giving their nature, and the epistemology [Wright,C]
13860 We can only learn from philosophers of the past if we accept the risk of major misrepresentation [Wright,C]
13867 Instances of a non-sortal concept can only be counted relative to a sortal concept [Wright,C]
13869 Number platonism says that natural number is a sortal concept [Wright,C]
13870 We can't use empiricism to dismiss numbers, if numbers are our main evidence against empiricism [Wright,C]
13868 Sortal concepts cannot require that things don't survive their loss, because of phase sortals [Wright,C]
13866 A concept is only a sortal if it gives genuine identity [Wright,C]
13865 'Sortal' concepts show kinds, use indefinite articles, and require grasping identities [Wright,C]
13873 Treating numbers adjectivally is treating them as quantifiers [Wright,C]
13877 Singular terms in true sentences must refer to objects; there is no further question about their existence [Wright,C]
17857 We can accept Frege's idea of object without assuming that predicates have a reference [Wright,C]
13882 A milder claim is that understanding requires some evidence of that understanding [Wright,C]
13883 The best way to understand a philosophical idea is to defend it [Wright,C]
13884 The idea that 'exist' has multiple senses is not coherent [Wright,C]
13885 If apparent reference can mislead, then so can apparent lack of reference [Wright,C]
13890 Entities fall under a sortal concept if they can be used to explain identity statements concerning them [Wright,C]
13888 If numbers are extensions, Frege must first solve the Caesar problem for extensions [Wright,C]
13893 It is 1-1 correlation of concepts, and not progression, which distinguishes natural number [Wright,C]
13892 One could grasp numbers, and name sizes with them, without grasping ordering [Wright,C]
13894 Sameness of number is fundamental, not counting, despite children learning that first [Wright,C]
13899 The Peano Axioms, and infinity of cardinal numbers, are logical consequences of how we explain cardinals [Wright,C]
13896 The aim is to follow Frege's strategy to derive the Peano Axioms, but without invoking classes [Wright,C]
13895 The standard objections are Russell's Paradox, non-logical axioms, and Gödel's theorems [Wright,C]
13898 If we can establish directions from lines and parallelism, we were already committed to directions [Wright,C]
7320 Holism cannot give a coherent account of scientific methodology [Wright,C, by Miller,A]
12189 Logical necessity involves a decision about usage, and is non-realist and non-cognitive [Wright,C, by McFetridge]