What we observe is not nature itself but nature exposed to our method of questioning. Our scientific work in physics consists in asking questions about nature in the language that we possess and trying to get an answer from experiment by the means that are at our disposal.

Even for the physicist the description in plain language will be a criterion of the degree of understanding that has been reached.

The Same organizing forces that have shaped nature in all her forms are also responsible for the structure of our minds.

...separation of the observer from the phenomenon to be observed is no longer possible.

Modern physics has changed nothing in the great classical disciplines of, for instance, mechanics, optics, and heat. Only the conception of hitherto unexplored regions, formed prematurely from a knowledge of only certain parts of the world, has undergone a decisive transformation. This conception, however, is always decisive for the future course of research.

Thus, the more precisely the position is determined, the less precisely the momentum is known, and conversely.

The ontology of materialism rested upon the illusion that the kind of existence, the direct "actuality" of the world around us, can be extrapolated into the atomic range. This extrapolation is impossible, however.