Werner Heisenberg Quotes

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

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.

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

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’.

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.

Natural science, does not simply describe and explain nature; it is part of the interplay between nature and ourselves.

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."

We may remark at this point that modern physics is in some way extremely near to the doctrines of Heraclitus. If we replace the word ‘fire’ by the word ‘energy’ we can almost repeat his statements word for word from our modern point of view. Energy is in fact the substance from which all elementary particles, all atoms and therefore all things are made, and energy is that which moves. Energy is a substance, since its total amount does not change, and the elementary particles can actually be made from this substance as is seen in many experiments on the creation of elementary particles. Energy can be changed into motion, into heat, into light and into tension. Energy may be called the fundamental cause for all change in the world.

We can never know anything.

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.

"Any concepts or words which have been formed in the past through the interplay between the world and ourselves are not really sharply defined with respect to their meaning: that is to say, we do not know exactly how far they will help us in finding our way in the world. We often know that they can be applied to a wide range of inner or outer experience, but we practically never know precisely the limits of their applicability. This is true even of the simplest and most general concepts like "existence" and "space and time". Therefore, it will never be possible by pure reason to arrive at some absolute truth.
The concepts may, however, be sharply defined with regard to their connections. This is actually the fact when the concepts become part of a system of axioms and definitions which can be expressed consistently by a mathematical scheme. Such a group of connected concepts may be applicable to a wide field of experience and will help us to find our way in this field. But the limits of the applicability will in general not be known, at least not completely."

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.

[F]rom all that has been said about modern science... modern physics is just one... but... characteristic, part of a general historical process... toward a unification and a widening of our... world. This... would... lead to a diminution of... cultural and political tensions that create the great danger... But... forces in the existing cultural communities... try to ensure for their traditional values the largest... role in the final state of unification... and thereby adds to the instability of the transient state. Modern physics... shows that the use of arms... would be disastrous, and... through it openness for all... concepts it raises the hope that in the final state of unification many different cultural traditions may live together and... combine different human endeavors into a new... balance between thought and deed, between activity and meditation.

Cautious deliberation based on purely rational arguments can save us from many errors and dangers. ...But ...there will always be a fundamental complementarity between deliberation and decision. ...The decision finally... pushing away all the arguments... The decision may be the result of deliberation, but it is... complementary... it excludes deliberation. Even the most important decisions... contain this inevitable element of irrationality. ...[I]t cannot be avoided that some real or apparent truth form the basis of life; and this fact should be acknowledged with regard to those groups... whose basis is different from our own.