QUANTUM MECHANICs AND OBJECTIVITY
A Study of the Physical Philosophy of Werner Heisenberg
By Patrick Heelan, S.J.
This book deals with the ‘crisis of objectivity ’or the ‘crisis of realism’ wlnch overtook physics when Heisenberg and Bohr, consciously rejecting the intentionality-structure of classical physics, gave physics a new form and a new philosophy. The new physics was called quantum mechanics, and the new philosophy complementarity. Using the method ‘analysis of horizons’ the author attempts to disentangle the epistemological and the ontological presuppusitions of Heisenberg’s view of complementarity. A similar analysis of Bohr’s view of complementarity reveals a remarkable contrast in basic philosophy betweenthe two founders of quantum physics. The author distinguishes various kinds of objectivity and realism and discusses critically the different aspects of the crisis that emerge in the quantum theory of measurement, the indeterminacy relations and in the statistical and causal structure of quantum mechanics.Heisenberg’s formulation of the crisis is traced to the underlying presuppositions of his thought. These presuppositions are criticised and shown to be defective. A more nuanced epistemological analysis reveals that quantum mechanics answers in a specially beautiful way the full exigencies of the human mind's knowledge of concrete reality. The author concludes that from the point of view of critical realist philosophy quantum mechanics is a coherent physical theory.