The history of science is everywhere speculative. It is a marvelous hiatory. It makes you proud to be a human being.

The attempt to make heaven on earth invariably produces hell.

It is part of my thesis that all our knowledge grows only through the correcting of our mistakes.

We never know what we are talking about.

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

A system such as classical mechanics may be 'scientific' to any degree you like; but those who uphold it dogmatically - believing, perhaps, that it is their business to defend such a successful system against criticism as long as it is not conclusively disproved - are adopting the very reverse of that critical attitude which in my view is the proper one for the scientist.

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