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Single Idea 9825

[filed under theme 9. Objects / A. Existence of Objects / 3. Objects in Thought ]

Full Idea

A thing (an object of our thought) is completely determined by all that can be affirmed or thought concerning it.

Gist of Idea

A thing is completely determined by all that can be thought concerning it

Source

Richard Dedekind (Nature and Meaning of Numbers [1888], I.1)

Book Ref

Dedekind,Richard: 'Essays on the Theory of Numbers' [Dover 1963], p.44


A Reaction

How could you justify this as an observation? Why can't there be unthinkable things (even by God)? Presumably Dedekind is offering a stipulative definition, but we may then be confusing epistemology with ontology.


The 23 ideas from 'Nature and Meaning of Numbers'

Dedekind proved definition by recursion, and thus proved the basic laws of arithmetic [Dedekind, by Potter]
Dedekind defined the integers, rationals and reals in terms of just the natural numbers [Dedekind, by George/Velleman]
Order, not quantity, is central to defining numbers [Dedekind, by Monk]
Ordinals can define cardinals, as the smallest ordinal that maps the set [Dedekind, by Heck]
Dedekind's axiom that his Cut must be filled has the advantages of theft over honest toil [Dedekind, by Russell]
Dedekind says each cut matches a real; logicists say the cuts are the reals [Dedekind, by Bostock]
Categoricity implies that Dedekind has characterised the numbers, because it has one domain [Rumfitt on Dedekind]
Dedekind gives a base number which isn't a successor, then adds successors and induction [Dedekind, by Hart,WD]
Zero is a member, and all successors; numbers are the intersection of sets satisfying this [Dedekind, by Bostock]
Induction is proved in Dedekind, an axiom in Peano; the latter seems simpler and clearer [Dedekind, by Russell]
Dedekind's ordinals are just members of any progression whatever [Dedekind, by Russell]
Dedekindian abstraction talks of 'positions', where Cantorian abstraction talks of similar objects [Dedekind, by Fine,K]
Dedekind said numbers were abstracted from systems of objects, leaving only their position [Dedekind, by Dummett]
Dedekind has a conception of abstraction which is not psychologistic [Dedekind, by Tait]
Numbers are free creations of the human mind, to understand differences [Dedekind]
In counting we see the human ability to relate, correspond and represent [Dedekind]
Dedekind originated the structuralist conception of mathematics [Dedekind, by MacBride]
An infinite set maps into its own proper subset [Dedekind, by Reck/Price]
Dedekind originally thought more in terms of mereology than of sets [Dedekind, by Potter]
A thing is completely determined by all that can be thought concerning it [Dedekind]
We have the idea of self, and an idea of that idea, and so on, so infinite ideas are available [Dedekind, by Potter]
A system S is said to be infinite when it is similar to a proper part of itself [Dedekind]
We derive the natural numbers, by neglecting everything of a system except distinctness and order [Dedekind]