Single Idea 9867

[catalogued under 6. Mathematics / A. Nature of Mathematics / 2. Geometry]

Full Idea

It will be ridiculous if our student knows the definition of the circle and of the divine sphere itself, but cannot recognize the human sphere and these our circles, used in housebuilding.

Gist of Idea

It is absurd to define a circle, but not be able to recognise a real one


Plato (Philebus [c.353 BCE], 62a)

Book Reference

Plato: 'Complete Works', ed/tr. Cooper,John M. [Hackett 1997], p.451

A Reaction

This is the equivalent of being able to recite numbers, but not to count objects. It also resembles Molyneux's question (to Locke), of whether recognition by one sense entails recognition by others. Nice (and a bit anti-platonist!).

Related Idea

Idea 3938 Geometry is originally perceived by senses, and so is not purely intellectual [Berkeley]