In one word, to draw the rule from experience, one must generalize; this is a necessity that imposes itself on the most circumspect observer.

Chance ... must be something more than the name we give to our ignorance.

It may happen that small differences in the initial conditions produce very great ones in the final phenomena. A small error in the former will produce an enormous error in the later. Prediction becomes impossible, and we have the fortuitous phenomena.

Analyse data just so far as to obtain simplicity and no further.

We also know how cruel the truth often is, and we wonder whether delusion is not more consoling.

All great progress takes place when two sciences come together, and when their resemblance proclaims itself, despite the apparent disparity of their substance.

It is far better to foresee even without certainty than not to foresee at all.