Physics and Reality
Bernard D'Espagnat, Reality and the Physicist Cambridge University Press, 1989, price £.10.95 pbk., pp. 280
Dugald Murdoch, Niels Bohr^s Philosophy of Physics, Cambridge University Press, 1989, price £.12.95, pbk., pp. 294
Stephen Hawking lamenting on the lack of reflection on fundamental questions both by scientists and philosophers observed, "most scientists have been too occupied with the development of new theories that describe what the universe is to ask the question why. On the other hand, the people whose business it is ask why, the philosophers have not been able to keep up with the advance of scientific theories". The two books under review go a long way in contributinjg to the elucidation of the complex relationship between present day physics and philosophy.
Murdoch's book, as the title suggests, elaborates, the philosophical ideas of Niels Bohr who contributed a great deal to the comprehensibility of 20th Century physics. The Copenhagen interpretation of quantum mechanics with Bohr's complimentarity and correspondence principles constitues the most efficacious explanation of the paradoxical nature of reality at the micro level. Several of Bohr's own statements and more so, those of the group of physicists around him at Copenhagen, gave the impression that the Copenhagen school denied the independent existence of reality if it was not being observed. A number ofidealistically inclined physicists and philosophers ascribed Tree will' to micro-entities and the probabilistic interpretation of micro-phenomena was taken as the final proof of the abandonment of the concept of causality. As against this Einstein who was not convinced of the logical completeness of quantum mechanics and raised repeated and highly ingeneous objections to Bohr's interpretation was considered classicist. Murdoch's book puts both Bohr's ideas and the famous Bohr-Einstein controversy into perspective. Murdoch argues that "Einstein's philosophy of science is much closer to Bohr's than either of these two physicists realised. Einstein's is less realist than Bohr suspected and Bohr's is less idealist than it seemed to Einstein". Regarding Bohr's philosophical ideas Murdoch quite convincingly shows that Bohr held the belief that our own sensory experience is of the real world of external objects whose existence is independent of our perception of them. Despite this strong realist component in Bohr's philosophy, which is characterised by Murdoch as 'instrumentalistic realism', he also traces the influences of pragmatism and Kantianism in Bohr's view of the goal of physical theories. Holding that the primary aim of physics reates to experience rather than to reality, Bohr regards physical theories primarily