Physics

Theoretical physicists live in a classical world, looking out into a quantum-mechanical world. The latter we describe only subjectively, in terms of procedures and results in our classical domain.

Physics is to be regarded not so much as the study of something a priori given, but rather as the development of methods of ordering and surveying human experience. In this respect our task must be to account for such experience in a manner independent of individual subjective judgement and therefor objective in the sense that it can be unambiguously communicated in ordinary human language.

There have indeed been civilizations upon your planet that understood as well as you, and without your kind of technology, the workings of the planets, the positioning of the stars -- people who even foresaw "later" global changes. They used a mental physics. There were men before you who brought back data quite as "scientific" and pertinent. There were those who understood the "origin" of your solar system far better than you. Some of these civilizations did not need spaceships. Instead, highly trained men combining the abilities of dream-art scientists and mental physicists cooperated at journeys not only through time but through space.