popper-logic-scientific-discovery

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based upon his famous formula E = mc 2 , Bohr had recourse to arguments
from Einstein’s gravitational theory (that is to say, from general
relativity). 10 But E = mc 2 can be derived from special relativity, and even
from non-relativistic arguments. In any case, in assuming E = mc 2 , we
certainly do not assume the validity of Einstein’s theory of gravitation.
If, therefore, as Bohr suggests, we must assume certain characteristic
formulae of Einstein’s gravitational theory in order to rescue the consistency
of quantum theory (in the presence of E = mc 2 ), then this
amounts, I hold, to the strange assertion that quantum theory contradicts
Newton’s gravitational theory, and further to the still stranger
assertion that the validity of Einstein’s gravitational theory (or at least
the characteristic formulae used, which are part of the theory of the
gravitational field) can be derived from quantum theory. I do not think
that even those who are prepared to accept this result will be happy
about it.
Thus we have again an imaginary experiment which makes
extravagant assumptions, with an apologetic purpose.
(7) David Bohm’s reply to the experiment of Einstein, Podolsky,
and Rosen seems to me also highly unsatisfactory. 11 He believes that he
has to show that Einstein’s particle A which has run far away from B
and from the measuring apparatus does nevertheless become smeared
in its position (or momentum) when the momentum (or position) of
B is measured, and he tries, to this end, to show that A, in spite of
having run away, is still interfered with in an unpredictable way. In this
way he tries to show that his own theory agrees with Heisenberg’s
interpretation of the indeterminacy relations. But he does not succeed.
This becomes manifest if we consider that the ideas of Einstein,
Podolsky, and Rosen allow us, by a slight extension of their experiment,
to determine simultaneously positions and momenta of both A
and B—although the result of this determination will have predictive
10 Bohr, in Albert Einstein: Philosopher-Scientist, ed. by P. A. Schilpp; the case is discussed on
pp. 225–228. Dr. J. Agassi has drawn my attention to the invalidity of the argument.
*We must remember that the ‘equivalence’ m i = m g is part of Newton’s theory.
11 See D. Bohm, Phys. Rev. 85, 1952, pp. 166 ff., 180 ff; see especially pp. 186 f. (I understand
that Bohm does not any longer uphold some of the views expressed in the papers
here criticized. But it seems to me that at least part of my argument may still be applicable
to his later theories.)