ABSTRACT
Bohr recommended complementarity as a criterion of completeness for explanations of quantum phenomena. To explain fully the single-slit diffraction of electrons, for instance, one must append two mutually exclusive pictures of the behavior of the electrons between the diaphragm and photographic plate. The two pictures are not applied arbitrarily. Spatiotemporal description is appropriate given a rigidly mounted diaphragm. Causal interaction—via energy/momentum transfer—is appropriate given a movable diaphragm. The biologist who studies an animal's behavior in a particular ecosystem cannot perform the dissections and chemical analyses to uncover the underlying physiological changes within the animal without compromising the original study. Bohr maintained that every experimental arrangement with which one could study the behavior of the atoms constituting an organism will exclude the possibility of maintaining the organism alive. Self-preservation and self-generation are processes fundamental to living organisms. Bohr maintained that the "notion of life" is an "element for which an explanation is neither possible nor required".
