Chaos cuts with two edges. We have seen how it is impossible to retrieve past history from current observations. We will now show that it is impossib… - Ivar Ekeland

It is a testimony to the power of education that classical mechanics could operate for so long under a mistaken conception. Teaching and research concentrated on integrable systems, each feeding the other, until in the end we had no longer the tools nor the interest for studying nonintegrable systems.

In the struggle for life, or in the struggle for power, there is no reason why their victory would make the world better than it was. There is no invisible hand guiding these processes, dealing out victory to the most deserving. Chance is their leader.

Nowadays, however, we are much more aware of the fact that the best proof in the world is worth no more than its premises: every scientific theory is transitory and provisional, in wait for a better one, and accepted only as long as the experimental results conform to its predictions.