86 Richard A. Muller Richard A. Muller In
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86 Time’s Books Richard A. Muller NOW: The Physics of Time. New York and London: Norton, 2016. 364pp. Richard A. Muller in NOW: The Physics of Time brings to the conversation about time the relatively new and most welcome perspective of an eminent experimental cosmologist. His book may well be, as he claims, “the only cur- rent book written specifically about time by a physicist deeply involved in experimental work” (8), for Muller, as Lee Smolin testifies “has initiated some of the most important experiments of our time” including at least one for which a former student of his, Saul Perlmutter, won a Nobel Prize. His book draws on years in the laboratory, and it is a lucid, highly original discussion of time replete with experiments to determine the existence and nature of time. During most of human history, time has proven a puzzle best left to philoso- phers and theologians. The most famous of these, St. Augustine, devoted a full chapter of his Confessions to a masterly line of reasoning about time which, despite some sniping over the centuries remains quite possibly the thorough discussion of the subject using logic, scripture, and reason. In contrast Muller’s gold standard for judging the truthfulness of assertions about time, as well as the relevance of evidence, is the scientist’s standard that, for any assertion or discovery to be true, it must be able to be falsified. If something is not falsifi- able then, he contends, while it may well prove valuable in other areas of life, it cannot be labeled as “true” or as a “fact.” The issue of falsifiability or lack of falsifiability underlies his painstaking refutation of Sir Arthur Eddington’s 1928 entropy arrow of time (160-76), which J. T. Fraser previously had rightly also doubted sufficient to prove a direction in time. Muller similarly criticizes Stephen Hawking’s 1988 discussion of an anthropic arrow of time (183-84). Muller charges Hawking with merely asserting that the anthropic arrow must be true or “we wouldn’t be discussing the issue. QED.” Such rationalizing he dismisses as “useless” (183). While he sees both Eddington’s and Hawking’s arguments as fatally flawed, his nemesis remains entropy, for in the 90 years since Eddington famously formulated his arrow of time as the arrow of entropy, no experiments have been completed, devised, or, even, proposed that might demonstrate its truth. Since correlation, he cautions, is not causation (172)—a good slogan for all experimentalists as well as a clear warning for all time- smiths—Eddington’s arrow of entropy does not account for the arrow of time. Taking a quite different tack, Muller builds his own theory upon Einstein’s “advances … in our understanding of time,” which he argues were “monumen- tal,” and on Richard Feynman’s addition of “backward time travel” (291). After their ground-breaking work, however, Muller believes, “progress in understand- ing time has been virtually nil” (291). He then proposes a new theory based © koninklijke brill nv, leiden, 2018 | doi 10.1163/15685241-12341406 Time’s Books 87 upon Einstein, Feynman, and recent discoveries and observations (rather than any of those various arrows), which he calls “the Cosmological Origin of Time” (296) or the “Now Theory of Time Creation” (302). Crucial for Muller’s theory of whichever title is the ongoing action of the Big Bang. Ever since initiating the 4D explosion of timespace, the Big Bang has been continuously expand- ing, and, as we’ve recently discovered, has also been continually accelerating. “Just as space is being generated by the Hubble expansion, so time is being created,” Muller argues (293). “The continuous and ongoing creation of new time sets both the arrow of time and its pace. Every moment the universe gets a little bigger and there is a little more time, and it is this leading edge of time that we refer to as now” (293 cf. 304). (This theory neatly sidesteps the problem presented by the absence of now in the physics of the non-living world since in Muller’s theory the new creation of time or new now creates the flow of time from past to present in the totality of the universe.) The implications for physics are considerable since in Muller’s theory “now is not movable. Now is the leading edge of the 4D Big Bang. Now is the moment that has just been created. The time axis for a true space-time diagram does not extend to infinity. Time stops at now” (293). The problem with past theo- ries, according to Muller, was their interpreting this “computational tool [the space-time diagram] as a deep truth” (304). His own painstakingly argued the- ory offers a radically different view of time from that of a large segment of con- temporary physics whose proponents maintain that time does not flow. His argument should also provoke intriguing responses from at least some of those many theoretical physicists who believe “that time fundamentally does not even exist.” (See Craig Callender, “Is Time an Illusion?” in Scientific American, June 2010: 41-47, note p. 41; compare Julian Barbour, The End of Time [London: Phoenix, 2000].) Muller also differs from many (most?) of his colleagues who posit a continuous present without a past or future; thus any notion of the past or future remains for them simply an illusion. Instead, he sees Now as continu- ally advancing as “the leading edge of time” (293). Time does flow according to his theory; there is both past and future; and the present continually arrives as space and time expand. As a result, only the past is determined, not the present in which humans have free will. Most importantly, this theory is pos- sibly falsifiable since time is linked to space, and since space is expanding at an accelerating rate “it is natural to expect that the rate of time is also accel- erating” and that clocks will “exhibit a cosmological time acceleration” that in principle could be “detected and measured …” (296). Because “[a] theory is of no use to science unless it is capable of being dis- proved,” as Julian Barbour cogently observed (358), Muller, unlike Eddington, suggests several experiments to do the necessary detection and measurement KronoScope 18 (2018) 81-98.