Metaphysics and Materialism

IN his article in NATURE of October 20 Prof. Carr maintains that the principle of relativity has “reformed” the concept of physical reality, and has finally made untenable the doctrine that matter is real. I dissent most strongly from his conclusion. If “real” is used in the only sense in which a belief in the reality of matter ever has been part of physics, that belief is entirely unaffected by the principle of relativity, which involves the belief as much as any other physical proposition. There may be senses of the word “real” in which the doctrine that matter is real is affected by the acceptance of the principle of relativity, but they are either repugnant to physics or irrelevant to it. I have explained my reasons for this opinion at length elsewhere, but at such length that nobody seems inclined to read them. May I be allowed to set them out rather more concisely?