by James Cushing
Introductory Essay by Victor J. Stenger
Philosophical Concepts in Physics covers the history and philosophy of physics from ancient times until today. While mathematical details are presented on every major development, these are mostly at the undergraduate level. However, the emphasis is not on the science itself but its philosophical interpretation. Considerable discussion of the philosophy of science is worked in for every historical epoch, with ample quotations of the people involved about how they viewed their work. Useful biographical material on all the great figures in physics history is also included. The underlying question is what, if anything, do the great discoveries in physics have to do with objective reality.
The book is divided into nine parts. In Part 1, The scientific enterprise, Cushing traces the history of philosophical thinking about science through five historical periods typified by (1) Plato and Aristotle, (2) Bacon and Descartes, (3) Galileo and Newton, (4) Hume and Mill, (5) Popper and Quine. Aristotle and Descartes believed that certain knowledge was possible by deduction from self-evident principles. Bacon said it was attainable by careful induction from experience. But, as Cushing points out, there is no logical way to arrive at first principles either from induction or deduction. One learns nothing from a deductive argument that is not already embedded in its premises. And, as Hume noted, the mere fact of one event following another does not imply any connection between the two, so the value of induction is also questionable.
In Part 2 Ancient and modern models of the universe, Cushing covers the Ptolmaic and Copernican models of the solar system, Kepler’s laws, and Galileo’s theories of motion. In Part 3, The Newtonian universe, Newton’s laws of motion and gravity are presented. In this and the previous part, considerable attention is given to the thought processes of two giants who helped trigger the scientific revolution. Part 4, A perspective, covers Galileo’s conflict with the Church. Cushing also discusses the implications of the Newtonian world-view compared with older views on issues such as the idea of space. He also raises the question of determinism, which will become a major theme of the book.
Part 5, Mechanical versus electrodynamical world views takes us through models of the aether, Maxwell’s theory of electromagnetism, and the precursors of relativity. Part 6, Relativity, goes though all the steps in developing both the special and general theories of relativity and their consequences for our view of the universe. In Part 7, The quantum world and the completeness of quantum mechanics, Cushing lays the groundwork for the remainder of the book, which concerns the still-unsettled questions concerning the ultimate meaning of quantum mechanics. Starting with Planck, the author quickly traces the early history and then introduces the Copenhagen interpretation and the question of completeness. The long-standing debate between Bohr and Einstein is discussed in detail.
Part 8, Some philosophical lessons from quantum mechanics, discusses in detail the EPR paradox, Bell’s theorem, and the alternative to the Copenhagen view provided by Bohm. The incompatibility between the indeterministic Copenhagen view and the deterministic Bohm view, which are indistinguishable empirically, is so profound that they cannot be regarded as equivalent. This throws doubt on any realistic interpretation of the theories. Curiously, no mention is made of some of the other variations of interpretations of quantum mechanics such as Many Worlds and Decoherent Histories.
Part 9. A retrospective, sums up the various issues covered and places them in a social context.
Philosophical Concepts in Physics belongs in every library that contains books on science and philosophy.