| 18152 | Russell takes numbers to be classes, but then reduces the classes to numerical quantifiers [Russell/Whitehead, by Bostock] |
| Full Idea: Although Russell takes numbers to be certain classes, his 'no-class' theory then eliminates all mention of classes in favour of the 'propositional functions' that define them; and in the case of the numbers these just are the numerical quantifiers. | |
| From: report of B Russell/AN Whitehead (Principia Mathematica [1913]) by David Bostock - Philosophy of Mathematics 9.B.4 |
| 18153 | A number is a repeated operation [Wittgenstein] |
| Full Idea: A number is the index of an operation. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.021) | |
| A reaction: Roughly, this means that a number indicates how many times some basic operation has been performed. Bostock 2009:286 expounds the idea. |
| 18160 | The concept of number is just what all numbers have in common [Wittgenstein] |
| Full Idea: The concept of number is simply what is common to all numbers, the general form of number. The concept of number is the variable number. | |
| From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.022) |