When you think of a scientist, you probably picture someone quietly doing experiments in a lab, not looking to hassle anyone. But that’s not always the case. Just like professional athletes, scientists love to question each other and argue their point, causing just as much drama as the Bears-Packers rivalry in football.
For example, the feud between Isaac Newton and Robert Hooke lasted for decades. Paleoanthropologists Donald Johanson (who discovered the Lucy fossils) and Richard Leakey got into it on an episode of Cronkite’s Universe, a show hosted by legendary television news anchorman Walter Cronkite. Then, of course, there was the most famous scientific smackdown—the bad blood between Nikola Tesla and Thomas Edison. And don’t forget the massive falling out between French scientists and American scientists over who first discovered the cause of the AIDS virus.
Whether it was backstabbing, name calling, or idea stealing, the spats between these scientists were very real and public.
More recently, the definition of “time” is under siege given a conceptual conflict in physics. According to Albert Einstein’s general theory of relativity, the universe is a fixed block where time is not real and everything happens simultaneously. Yet a handful of quantum physicists hope to replace this “block universe” with a physical theory where time not only exists but flows from past to future.
While there’s no nasty politicking or knife sticking so far, the rivalry between the two camps nevertheless exists. And let’s hope the physical theory team wins because if they don’t, time, as we experience it in a block universe, is weirdly at odds with our everyday experience, and everything—past and future—has already happened, which robs us of free will.
Yep, you read that right: in a block universe everything for you is already planned and your destiny has already been decided. Which means you are not able to choose what you will do with our life. Everything that has ever been and ever will be is happening right now.
I know, I know. It seems bizarre. Time feels real, always there, unavoidably ticking away, moving like a river, unstoppably dragging us with it. The debate is whether these feelings are actual realities of the physical world or just a trick of the mind.
Even if you had trouble with high school physics, like me, and are not interested in feuding scientists, this is mind-boggling stuff. To Einstein, the universe must obey the laws of physics that are fundamentally deterministic, and in respect to that he argued against free will. In Einstein’s mind, all behavior is caused by preceding events and is thus predictable. Let me give you an example.
Let’s say you’re playing a round of golf. Before you hit a tee shot you pick a target. You practice your swing a couple of times, then you make contact with the ball. If you could stop time at that exact instant, you could predict with a reasonable degree of certainty the outcome of your shot. The golf club determines the path of the golf ball, and the path of the golf ball determines if and how it will hit the target.
But even before that, your body motion determines the path the club takes down to the ball. And that’s determined by the neurons in your brain, which, like everything else in the universe, must obey the laws of physics. So monitoring and measuring your brain activity would predict how hard you swing before you’re aware of making that decision. And since physics determines that decision, physics determines all your decisions—including whether you opt for a driver or a 3-wood.
This golfing example represents determinism. Here’s Einstein on determinism: “Everything is determined, the beginning as well as the end, by forces over which we have no control. It is determined for the insect as well as for the star. Human beings, vegetables, or cosmic dust, we all dance to a mysterious tune, intoned in the distance by an invisible player.”
So, is this really how things work? Do all events already exist in a block universe of Einstein’s relativity?
To explain what a block universe looks like, think of a brick. It has three dimensions—up and down, left and right, back and forth. But according to Einstein we live in four dimensions—the three spatial dimensions plus one time dimension. A block universe is a four-dimensional brick. But instead of being made of clay, it’s made of spacetime. And all the space and time of the universe are in that brick, with every event having its own coordinates or address.
So if you were to take a step back and stand outside the brick (outside space and time) you would see a series of snapshots of every event that has ever happened or will ever happen. If you line up these photos, you would make a movie of everything from the birth of the universe and the formation of Earth to the time of the dinosaurs and what’s happening today—you walking to the first tee, sinking a putt on the 18thgreen, and what happens in between. From this perspective, although time is static and fixed, it appears to flow.
At this point you might be saying, “My golfing buds would laugh if I told them I can predict their score card with the right brain-monitoring equipment.” But for many physicists this view is the one that best aligns with the theories of space and time supported by relativity. In a block universe, past, present, and future are all individual points. Even Einstein himself said, “People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.”
Just think about that for a second. Even a serial killer, according to this view, is living out a future that has already been set. So it would be meaningless to tell this person they are doing something terrible. Just like that next scene in the movie you’ve seen a dozen times on cable, you know what’s coming next and the characters have no say in the matter—no free will. Einstein believed that. But he also believed killers should be put in jail.
A physical theory of time, on the other hand, rejects Einstein’s notion that time is just another dimension in space and the future is just as decided as the past. Your mind is not a device that can be completely predicted, like a golf club striking a ball. You make choices, and the molecules and cells of your brain, which, according to relativity were predetermined since the very moment of the Big Bang, did not already decide whether you go with the driver over the 3-wood. The future isn’t already written. The Colorado man accused of murdering his pregnant wife and his two daughters last month had a choice. We cannot know exactly how something will turn out before it happens.
Science has long known that quantum mechanics and general relativity are conflicting. And even if you know nothing about science, you probably know that the holy grail of physics is unifying these two theories in order to formulate a single theory that fully explains all physical aspects of the universe. We’ve all heard the term the “theory of everything.”
That said, there are a few things that both camps agree on. One is that the quantum world is mind-bogglingly weird. Here’s a taste of the weirdness: There is nothing amazing about cracking a few eggs when you wake up in the morning and beating them with a fork. But if you decide you want cereal instead, the idea that you could unscramble the eggs and make them whole eggs again seems impossible. The “arrow of time” only goes one way: forward.
But asking why we live in a universe where such a law holds is where things get tricky.
Scrambling eggs is an illustration of increasing entropy—a tendency of the universe to go from order to disorder, from an ice cube to a puddle of water. We perceive this as time flowing forward. And it is because events in the past cause events in the present that cause events in the future that we rebel against the idea that time does not pass.
But here’s a doozy for you. Quantum theory says entropy can also increase going backward in time, which means unscrambling scrambled eggs and making them whole again is possible.
But here’s the catch: there are so many more ways for eggs to arrange themselves broken than whole that the chance of it happening is so astronomically small you’d have to wait longer than 13.8 billion years, the age of the universe, for it to happen. Even then, odds are it may never happen. So don’t hold your breath. Same with unstiring the cream in your morning cup of joe. Won’t happen. And while it is theoretically possible to be born eighty years old and grow younger as time passes like Brad Pitt did in the movie The Curious Case of Benjamin Button, it’s infinitely more likely that it won’t.
What does that imply for the concept of free will?
To begin with, free will can only exist if there are different possible futures and you are able to influence which one becomes reality. In Einstein’s deterministic universe, this isn’t the case—there’s only one future.
But the key point for quantum time is that there are an infinite number of possible futures. Even scrambled eggs can unscramble.
It all has to do with something called Heisenberg’s Uncertainty Principle, first introduced in 1927 by the German physicist Werner Heisenberg.
Unlike Einstein’s deterministic universe, where everything follows clear-cut laws and prediction is easy, the uncertainty principle throws a level of fuzziness into the picture. In a nutshell, Heisenberg said we cannot predict the precise position and momentum of a sub-atomic particle at any given moment, so its future cannot be determined. Translated into golf, this means that the outcome of your tee shot cannot be exactly predicted, or “determined,” from the knowledge of the neurons in your brain.
So, what conclusions can we draw?
With Einstein quite possibly the smartest man who ever lived, it would seem that relativity governs just about everything from a macroscopic perspective. I’m not a scientist, I remind you, and so while I have a casual understanding on the basic ideas of relativity, I cannot pretend to understand the specifics. What I do know is that an increasing number of quantum physicists are making the point that at the molecular level Einstein was wrong about time. I for one hope they are right.
The bottom line is that time is not as simple as it seems to you and me. Are the physical physicists right? Or is time really just an illusion, as most conventional theorists bizarrely insist? There are no concrete answers.
Personally, I think you shouldn’t worry too much about it. Time will tell who is right. “One after another,” Italian physicist Carlo Rovelli wrote in his new book The Order of Time, “the characteristic features of time have proved to be approximations, mistakes determined by our perspective, just like the flatness of the Earth or the revolving of the sun.” You can learn more about Rovelli’s book here.
The thing is, while what Rovelli says might be true, I’m not standing to the side and waiting while physicists figure it out. I’ll never, ever believe anyone who tells me I have no control over my actions. I’m not buying that everything that’s happening this morning—like my decision to write this piece, or my wife driving to her workout class—is caused by events that happened before it. I’m living my life believing I have full control of my behavior. Are you?