All the scientist creates in a fact is the language in which he enunciates it. If he predicts a fact, he will employ this language, and for all those who can speak and understand it, his prediction is free from ambiguity. Moreover, this prediction once made, it evidently does not depend upon him whether it is fulfilled or not.

Experiment is the sole source of truth.

A cat is witty, he has nerve, he knows how to do precisely the right thing at the right moment.

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.

Geometry is the art of correct reasoning from incorrectly drawn figures.

Mathematicians do not study objects, but the relations between objects.

All the scientist creates in a fact is the language in which he enunciates it. If he predicts a fact, he will employ this language, and for all those who can speak and understand it, his prediction is free from ambiguity. Moreover, this prediction once made, it evidently does not depend upon him whether it is fulfilled or not.