A theory is just a mathematical model to describe the observations.

A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice.

Serious rational criticism is so rare that it should be encouraged. Being too ready to defend oneself is more dangerous than being too ready to admit a mistake.

Science may be described as the art of systematic over-simplification.

Those who promise us paradise on earth never produced anything but a hell.

Piecemeal social engineering resembles physical engineering in regarding the ends as beyond the province of technology.

The attempt to make heaven on earth invariably produces hell.