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Single Idea 5623

[from 'Critique of Pure Reason' by Immanuel Kant, in 2. Reason / A. Nature of Reason / 1. On Reason ]

Full Idea

If I know that the earth is a sphere, and its surface the surface of a sphere, then from a small part of the latter I can know the diameter, and hence the complete boundary, and in accordance with a priori principles.

Gist of Idea

If I know the earth is a sphere, and I am on it, I can work out its area from a small part

Source

Immanuel Kant (Critique of Pure Reason [1781], B787/A757)

Book Reference

Kant,Immanuel: 'Critique of Pure Reason', ed/tr. Guyer,P /Wood,A W [CUO 1998], p.653


A Reaction

A nice example, though it may be optimistic in its assumption that you can know you are on a sphere rather than an egg-shape. I agree with Kant, but speculative metaphysics should always be accompanied by humility and health warnings.