EINSTEIN ON ONE OF THE CENTRAL TENETS OF THE THEORY OF RELATIVITY.
Written to Chicago labor organizer Ruth Levitova:
Your conception of time is the only one possible in accordance with physics - for the following reasons:
1): Physics knows only different values of time but has no possibility of expression for 'now' (present), for 'past' and for 'future'.
2): Even if one adds to physics the (psychologically so impressively given) 'I-now' there exists - according to the theory of relativity - no possibility to coordinate with the 'I-now' unequivocally a 'present state of the universe'. This feature of exact science was keenly felt and attacked by Henri Bergson (in my opinion without justification).
[signed] A. Einstein
Already famous for his General Theory of Relativity and for the light quantum hypothesis, for which he was awarded the 1921 Nobel Prize in Physics, Einstein, in the 1920s, attempted to develop a new theory to explain the effects of all fundamental forces - a unified field theory, for which his General Theory was instrumental.
Einstein’s Special Theory of Relativity, the core formula of which is E=mc², had explained the relativity of space and time and the relationship between energy and matter. But after the theory’s publication in 1905, Einstein recognized the need to account for the effect of gravity on space and time, culminating in his updated General Theory of Relativity, published in 1916, with its central formula (Rik - ½gikR) + (Eik) = 0. Questions about gravity continued to dominate Einstein’s thoughts for the rest of his life during his search for a unified field theory of gravity.
Levitova was identified as a member of the Communist Party of Chicago during the September 1952 hearings of the House Un-American Activities Committee. She was a field representative of United Electrical, Radio and Machine Workers of America Local 1150 and had corresponded with Einstein during 1933. Despite repeated attacks on the union from the HUAC, the UE is still in existence today.
Princeton: May 13, 1952. One (8.5x11in) sheet (written on one side). In excellent condition; on the letterhead of the Institute for Advanced Study, with original envelope.