Is time real?


First aired on Quirks & Quarks (20/04/13) 

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As generations of physicists have worked assiduously to uncover the laws of physics, it's been harder and harder to avoid a strange and counter-intuitive conclusion: Time, as we commonly understand it, isn't real. Einstein, for example, demonstrated that it is malleable, and dependent on your frame of reference. But some scientists and philosophers are now fighting for time. They're turning the tables and bringing forward new theories which suggest that not only may time exist, but that the laws of physics themselves are less stable than we might think. Dr. Lee Smolin, a founding and senior faculty member at the Perimeter Institute for Theoretical Physics in Waterloo, Ont., lays out that claim in his new book, Time Reborn: From the Crisis in Physics to the Future of the Universe.

Physicists have conjured two differing concepts of reality, Smolin told Quirks & Quarks' Bob McDonald in a recent interview. In the first, the laws of physics are primary and unchanging. In this concept, time is an illusion, as a completely predetermined future exists.

"You could work out in a computer what the positions of all the atoms would be at any future time," he said. "Everything that's going to happen is already determined in the present state of the world and by the laws of physics."

In the second concept, which is Smolin's preferred vision, time is primary. Laws are temporary generalizations, which hold true for an amount of time in certain regions of the universe, and act as useful tools to deduce phenomenon. But over the largest scales of space and time, they have the capacity to change.

Smolin invokes the Big Bang theory as an example. Many note the Big Bang as the first moment in time, but Smolin says "to believe that is to believe a kind of mysticism." Instead, we can think of the Big Bang as an event that transitioned the universe from a prior era. That transition can change everything at least a little bit -- even the laws of physics.

If the laws are changeable, scientists can ask concrete questions about the processes that govern the changes. From a scientific perspective this opens new possibilities for investigation, observation and experiment, and a way to get at more fundamental questions of our reality.  But on a more philosophical note, in this version of reality time exists, determinism is undermined, and human choice and free will may have more meaning.  Smolin prefers this, saying he used to look at his son and think in some sense his fate was predetermined.

"Now when I look at my child I think his future is open," he said.

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