Figure 4.1. Solvay Conference, Brussels, Belgium, 1927.In 1932 very little was known about the molecular components
of living organisms, and pretty much nothing was known about the
physical basis of heredity and the nature of the gene. In his lecture,
Bohr speculated that in order to study the structure and function
of living organisms at the subcellular level, it would be necessary to
probe the cell with measuring instruments, and that such probing
actions would necessarily perturb and disrupt the molecular compo-
nents of the cell in profound ways. Such disturbances could include
robbing the life from (that is, killing) the very living organism one was
wishing to study in order to get at the physical basis of life. In Bohr’s
words:
We should doubtless kill an animal if we tried to carry the investigation
of its organs so far that we could describe the role played by single atoms
in vital functions. ... And the idea suggests itself that the minimal free-
dom we must allow the organism in this respect is just large enough to
permit it, so to say, to hide its ultimate secrets from us.The comparable situation in physics would be the measurement of
properties of atoms and molecules, where the measurement process
necessarily perturbs and changes the phenomena being measured.
Classical physics was inadequate to describe the results obtained
when measurements were made on atoms, and an entirely new math-
ematical-physical framework, quantum mechanics, had to be devel-
oped. The consequence was one of the most exciting things that had
ever taken place in the history of science.
Thus, Bohr goes on to say, perhaps an analogous scenario might
play out in biology: that in trying to elucidate the submicroscopic