NEW YORK — Is time real, or the ultimate illusion?
Most physicists would say the latter, but Lee Smolin challenges this orthodoxy in his new book, "Time Reborn" (Houghton Mifflin Harcourt, April 2013), which he discussed here Wednesday (April 24) at the Rubin Museum of Art.
In a conversation with Duke University neuroscientist Warren Meck, theoretical physicist Smolin, who's based at Canada's Perimeter Institute for Theoretical Physics, argued for the controversial idea that time is real. "Time is paramount," he said, "and the experience we all have of reality being in the present moment is not an illusion, but the deepest clue we have to the fundamental nature of reality." [Album: The World's Most Beautiful Equations]
Smolin said he hadn't come to this concept lightly. He started out thinking, as most physicists do, that time is subjective and illusory. According to Albert Einstein's theory of general relativity, time is just another dimension in space, traversable in either direction, and our human perception of moments passing steadily and sequentially is all in our heads.
Over time, though, Smolin became convinced not only that time was real, but that this notion could be the key to understanding the laws of nature.
"If laws are outside of time, then they're inexplicable," he said. "If law just simply is, there's no explanation. If we want to understand law … then law must evolve, law must change, law must be subject to time. Law then emerges from time and is subject to time rather than the reverse."
Smolin admitted there are objections to this idea, especially what he calls "the meta-law dilemma:" If physical laws are subject to time, and evolve over time, then there must be some larger law that guides their evolution. But wouldn't this law, then, have to be beyond time, to determine how the other laws change with time? Other physicists have cited this objection in reaction to Smolin's work.
"The problem I see with the argument for laws that evolve in time is one that you yourself identify in the book: what you call the 'meta-laws dilemma,'" Columbia University physicist Peter Woit wrote on his blog Not Even Wrong. "You speculate a bit in the book on ways to resolve this, but I don't see a convincing answer to the criticism that whatever explanation you come up with for what determines how laws evolve, I’m free to characterize that as just another law."
Smolin admitted this is currently a sticking point, but maintained that there are possible solutions.
"I believe you can resolve the meta-law dilemma," Smolin said at the Rubin event. "I think the direction of 21st-century cosmology will depend on the right way to resolve the meta-law dilemma."
Smolin and Meck discussed the consequences of his idea, including what it means for our understanding of human consciousness and free will. One implication of the idea that time is an illusion is the notion that the future is just as decided as the past.
"If I think the future's already written, then the things that are most valuable about being human are illusions along with time," Smolin said. "We still aspire to make choices in life. That is a precious part of our humanity. If the real metaphysical picture is that there are just atoms moving in the void, then nothing is ever new and nothing's ever surprising — it's just the rearrangement of atoms. There's a loss of responsibility as well as a loss of human dignity."
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Clara Moskowitz is a science and space writer who joined the Space.com team in 2008 and served as Assistant Managing Editor from 2011 to 2013. Clara has a bachelor's degree in astronomy and physics from Wesleyan University, and a graduate certificate in science writing from the University of California, Santa Cruz. She covers everything from astronomy to human spaceflight and once aced a NASTAR suborbital spaceflight training program for space missions. Clara is currently Associate Editor of Scientific American. To see her latest project is, follow Clara on Twitter.