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Single Idea 18110

[filed under theme 6. Mathematics / A. Nature of Mathematics / 5. The Infinite / k. Infinitesimals ]

Full Idea

Non-standard natural numbers will yield non-standard rational and real numbers. These will include reciprocals which will be closer to 0 than any standard real number. These are like 'infinitesimals', so that notion is not actually a contradiction.

Gist of Idea

Infinitesimals are not actually contradictory, because they can be non-standard real numbers

Source

David Bostock (Philosophy of Mathematics [2009], 5.5)

Book Ref

Bostock,David: 'Philosophy of Mathematics: An Introduction' [Wiley-Blackwell 2009], p.155


The 9 ideas with the same theme [items too small to be measured]:

Things get smaller without end [Anaxagoras]
Nature uses the infinite everywhere [Leibniz]
A tangent is a line connecting two points on a curve that are infinitely close together [Leibniz]
Infinitesimals are ghosts of departed quantities [Berkeley]
Values that approach zero, becoming less than any quantity, are 'infinitesimals' [Cauchy]
Weierstrass eliminated talk of infinitesimals [Weierstrass, by Kitcher]
Infinitesimals are not actually contradictory, because they can be non-standard real numbers [Bostock]
With infinitesimals, you divide by the time, then set the time to zero [Kitcher]
Infinitesimals do not stand in a determinate order relation to zero [Rumfitt]