FOUNDATIONS OF QUANTUM MECHANICS

VI
BOHMIAN MECHANICS
My suggestion is that at each state the proper order of operation of the mind requires
an overall grasp of what is generally known, not only in formal, logical, mathematical
terms, but also intuitively, in images, feelings, poetic usage of language, etc.
— David Bohm
But why then had Born not told me of this “pilot wave?” If only to point out what was
wrong with it? [. . . ] Why is the pilot wave picture ignored in text books? Should it not be
taught, not as the only way, but as an antidote to the prevailing complacency? To show
that vagueness, subjectivity, and indeterminism, are not forced on us by experimental
facts, but by deliberate theoretical choice?
— John Bell
We briefly describe Bohm’s hidden variables theory, which we will call Bohmian mechanics.
Bohmian mechanics seems to have the same empirical strength as quantum mechanics, but succeeds
to provide an image in space and time of what exactly takes place in micro - physical reality.
VI. 1
INTRODUCTION
The debate between Bohr and Einstein concerning the interpretation of quantum mechanics
reached its peak in the 1935 EPR - article. Although both authors frequently returned to the problems,
neither of them has afterwards introduced new elements in his point of view. For most of
the physicists in the nineteen thirties and later it was not difficult to declare a winner to the debate,
Bohr’s view was accepted nearly unanimously. The question whether a physical reality hides behind
quantum mechanics, which exists of objects having properties and of which we can form ourselves a
picture in space and time, was put aside. It was also thought that Von Neumann’s proof, as discussed
in V. 2, p. 114, made a hidden variables reconstruction of quantum mechanics untenable.
It is the merit of Bohm to have made a breach in the Copenhagen interpretation for the first time,
by doing exactly that what was impossible or meaningless according to the Copenhageners. In 1952
he published two articles in which he presented a HVT of quantum mechanics. In the second article
he describes the breach as follows (Bohm 1952 part II, p. 188)
The usual interpretation of the quantum theory implies that we must renounce the possibility
of describing an individual system in terms of a single precisely defined conceptual
model. We have, however, proposed an alternative interpretation which does not imply