[T]he different branches of Arithmetic - Ambition [G]eometry is not true, it is advantageous.

Thus, be it understood, to demonstrate a theorem, it is neither necessary nor even advantageous to know what it means.

Experiment is the sole source of truth.

. . . by natural selection our mind has adapted itself to the conditions of the external world. It has adopted the geometry most advantageous to the species or, in other words, the most convenient. Geometry is not true, it is advantageous.

Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house.

It is with logic that one proves; it is with intuition that one invents.

A small error in the former will produce an enormous error in the latter.