细节
ALBERT EINSTEIN (1879-1955)
A one-page typed letter, signed, on paper headed The Institute for Advanced Study, School of Mathematics, Princeton, New Jersey, dated 30 October 1943, to John J. Bowman, thanking him for his letter and explaining in concise terms how the theory of relativity has abolished the concept of Aether in one sense but retained it in another. "In the times when the concept of Aether played an important role in theoretical physics it was thought to be something in empty space, what has a close analogy with continuous matter," Einstein states. "In an abstract sense the meaning was this: to the point Po in empty space, taken at a certain time t o correponds a point P in every other time t. There are world lines in empty space through every point P which have a physical meaning. The abolition of this idea is a characteristic feature of the theory of relativity."
In a shorter, second paragraph, Einstein grants that: "The word Aether is also used in a more general sense to express the idea of a continuous field in the physical space. Taken in this sense the concept of Aether has been maintained. But it seems to me that taken in this sense the concept is superfluous for it adds nothing to the concept of field" (erased pencil note by the receipient on verso, very slight marginal browning), in original envelope.
