Quotes from Werner Heisenberg

I would say that I was absolutely convinced of the possibility of our making an uranium engine, but I never thought that we would make a bomb; and at the bottom of my heart, I was really glad that it was to be an engine and not a bomb.

Not only is the Universe stranger than we think, it is stranger than we can think.

What we observe is not nature itself, but nature exposed to our method of questioning.

The first gulp from the glass of natural sciences will turn you into an atheist, but at the bottom of the glass God is waiting for you.

There are things that are so serious that you can only joke about them.

I remember discussions with Bohr which went through many hours till very late at night and ended almost in despair; and when at the end of the discussion I went alone for a walk in the neighbouring park I repeated to myself again and again the question: Can nature possibly be so absurd as it seemed to us in these atomic experiments ?

The reality we can put into words is never reality itself.

An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them.

Quantum theory provides us with a striking illustration of the fact that we can fully understand a connection though we can only speak of it in images and parables.

I think that modern physics has definitely decided in favor of Plato . In fact the smallest units of matter are not physical objects in the ordinary sense; they are forms, ideas which can be expressed unambiguously only in mathematical language.

T]he atoms or elementary particles themselves are not real; they form a world of potentialities or possibilities rather than one of things or facts.

Revere those things beyond science which really matter and about which it is so difficult to speak.

The positivists have a simple solution: the world must be divided into that which we can say clearly and the rest, which we had better pass over in silence. But can anyone conceive of a more pointless philosophy, seeing that what we can say clearly amounts to next to nothing? If we omitted all that is unclear, we would probably be left completely uninteresting and trivial tautologies.

I am firmly convinced that we must never judge political movements by their aims, no matter how loudly proclaimed or how sincerely upheld, but only by the means they use to realize these aims.

My mind was formed by studying philosophy, Plato and that sort of thing.

The existing scientific concepts cover always only a very limited part of reality, and the other part that has not yet been understood is infinite. Whenever we proceed from the known into the unknown we may hope to understand, but we may have to learn at the same time a new meaning of the word 'understanding'.

Whether we like it or not, modern ways are going to alter and in part destroy traditional customs and values.

In classical physics, science started from the belief – or should one say, from the illusion? – that we could describe the world, or least parts of the world, without any reference to ourselves.

Only a few know, how much one must know, to know how little one knows

In a darkened world no longer illuminated by the light of this center [God], technical advances are scarcely more than despairing attempts to make Hell a more agreeable place to live in. This must be particularly emphasized against those who think that by spreading the civilization of science and technology even to the uttermost ends of the earth, they can furnish all the essential preconditions for a golden age. One cannot escape the Devil so easily as that.

The probability wave] meant a tendency for something. It was a quantitative version of the old concept of potentia in Aristoelian philosophy. It introduced something standing in the middle between the idea of an event and the actual event, a strange kind of physical reality just in the middle between possibility and reality.

Here the attention of the research workers is primarily directed to the problem of reconciling the claims of the special relativity theory with those of the quantum theory. The extraordinary advances made in this field by Dirac ... leave open the question whether it will be possible to satisfy the claims of the two theories without at the same time determining the Sommerfeld fine-structure constant.

The renouncing of life and immediacy, which was the premise for the progress of natural science since Newton, formed the real basis for the bitter struggle which Goethe waged against the physical optics of Newton. It would be superficial to dismiss this struggle as unimportant: there is much significance in one of the most outstanding men directing all his efforts to fighting against the development of Newtonian optics.

We can never know anything.