From error to error one discovers the entire truth.

I am actually not at all a man of science, not an observer, not an experimenter, not a thinker. I am by temperament nothing but a conquistador

The price we pay for our advance in civilization is a loss of happiness through the heightening of the sense of guilt.

What a distressing contrast there is between the radiant intelligence of the child and the feeble mentality of the average adult.

It is a mistake to believe that science consists in nothing but conclusively proved propositions, and it is unjust to demand that it should. It is a demand made by those who feel a craving for authority in some form to replace the religious catechism by something else, even a scientific one.

When a love-relationship is at its height there is no room left for any interest in the environment; a pair of lovers are sufficient to themselves

The view is often defended that sciences should be built up on clear and sharply defined basal concepts. In actual fact no science, not even the most exact, begins with such definitions. The true beginning of scientific activity consists rather in describing phenomena and then in proceeding to group, classify and correlate them.