What is time? Philosophically and scientifically, that’s a hard question to answer. Can anyone even tell us how many books have been written about time? Here are some of my questions:
- Is there one eternal now that exists everywhere, throughout all of reality, in this universe, and all the other universes of the multiverse?
- Is time just the 4th dimension? Does the first three dimensions move through a fourth?
- Does time actually exist, or is it just an illusion?
- Why and how do we feel time?
- What is the smallest unit of time?
- If something has been ticking since the Big Bang, what is that tick?
- Is time mental or physical?
- Will time stop if the average temperature of the universe reaches 0 degrees Kelvin?
- Is time just change? The motion of atoms, the turning of the Earth, our orbit around the sun, the unfolding of existence since the Big Bang?
- Is the astronaut traveling near the speed of light, 300 hundred years ahead of us, time traveling? How could two twins move into two different nows?
- Is the now of this space-time different from the now of another space-time universe somewhere else in the multiverse, or is there one universal now in all of reality?
- Are the past and future illusions?
- Is there a beginning or end of time?
- Is time travel possible?
- Are there beings that see all of time at once, as if we’re looking across a vast three dimensional space?
- Is there anything outside of time?
- Do animals sense time?
- Would time exist without us?
- Is it possible to have two nows?
- If there is only now, does it matter what time it is?
- If we didn’t measure time would we think it existed?
Time Reborn by Lee Smolin, is a book about physics by a physicist who makes a scientific case for time to be real, and what that means philosophically and for physics. If you are not a physicist, or a fan of popular science books, I’m not sure if I can recommend this book to you as fun reading. It is hard to comprehend all the subtle implications involved with the physics of time. However, if you have a philosophical bent, it might be worth considering. Smolin is making a case that time exists, that it has a direction, and that reality is evolving.
Classical physics always models the universe in mathematics, and quite often time either doesn’t exist, doesn’t matter, or the equations work regardless of the direction of time. Ever since Einstein, scientists have searched for a grand unified theory of everything, hoping to find elegant equations that explained reality. Smolin rejects this goal by making a case that the universe can’t completely be described in mathematics.
To the average person, with common sense, they will reply, “Duh!” Isn’t it obvious that time exists. Isn’t obvious that time has a direction. Isn’t it obvious that mathematics can’t explain everything. Our everyday reality is very far from Big Bang cosmology and quantum physics. Physicists are trying to explain everything, and often it’s easy to ignore the immediate world. When you’re number crunching complex equations to explain reality it’s easy to think time can be ignored, or even space. But black box simulations of the universe aren’t modeling the real universe.
It’s hard to know exactly what Smolin is saying because he gives us so many possibilities to consider, but the epilogue suggests why he wrote the book, to make a philosophical statement. What I got out of the book might not be what Smolin intended, but here’s how I read him.
Smolin wants us to accept time. He wants us to reject the siren song of the timeless. He warns us to be wary of timeless concepts of the universe, whether it’s religion, whether its a mathematical expression, whether it’s a simulation, or even Platonic ideals. Mathematics can approximate some features of the universe, models can simulate some features, but ultimately, people like Max Tegmark and Juan Maldacena are wrong. And reality is neither a creation of God or solipsistic dream.
If time is real, and the universe is evolving, either from the Big Bang, or earlier causes in the multiverse, and there is a universal now, with a past and a future. Smolin doesn’t say it directly, but reality isn’t about us. He’s against the anthropomorphic principle. Realty would have existed without us. We just accidently happened to evolve in a universe that is suitable for life – it wasn’t created for us.
Ultimately, there are limits to what science can see or detect, and to understand. We can’t know why there is something rather than nothing. We have a lot more we can learn about this universe, and we may even learn something about the multiverse, but the ultimate cause of existence is probably beyond physics. To say that time exists does not mean we can prove time origin and end.
That’s the problem with humans. Our religious and philosophical natures want timeless answers to the big ontological questions. Physicists want timeless equations to explain everything. The implication is, if time really exists, then timeless answers don’t.
Ever since I’ve finished this book I’ve tried to meditate on time. To slow my thoughts and focus, hopefully to catch the ticking of time passing. But I can’t. All I can do is notice the slightest changes of things around me. I feel if nothing moved, time would stop, but there’s always something moving. We live in an eternal now.
We have no recollection of events before our existence, nor will we be aware of things after we’re gone.
We can only be here now.
JWH – 3/31/14