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When I say “the universe”, what do you immediately think of?
Me, I think of an old documentary with dark pictures and lots of equations. Maybe Morgan Freeman is narrating. Maybe someone with a British accent is narrating. In my imagination, I’m flying through a supernova, galaxies, and a weird purple plasma-like goo that I like to imagine as dark matter.
Most of what we know about the universe is through math. All throughout scientific history, we made observations and derived math to help predict the future from our observations. So far, we’ve been remarkably successful in predicting things like planetary motion, simple harmonic motion, and even gravitational waves!
Who knows what we will able to predict next.
But there is still much too be discovered. In fact, there seems to be an “infinite sea of unknowability” to sift through.
One of the most glaring unknowabilities, many would argue, is the origin of life. And (an entirely different can of worms) what is life?
The problem is like this: The universe began expanding rapidly (probably) according to the laws of physics. Fast forward billions of years and POOF! Life on Earth.
Laws of physics. Then life.
The first question to ask: “Is life embedded in the laws of physics?”
The second to ask: “If the universe started an infinite number of times, would life emerge every single time?”
As of right now, there is no clear answer to either of these questions. Nothing about Newton’s laws of motion hints at microbial life, so this problem almost seems impossible to approach using the laws of physics. Are there laws of physics we aren’t accounting for? Or are there special combinations of physics that eventually give life? It isn’t as obvious as one might think.
One way to view the universe is in terms of states, functions, and computation. If the universe has all its particles arranged in one particular way, we can call it a state. Move one of those particles, or a few, and we get a different state. A function is what moves one state to another state. This entire process is a computation. Using this definition, the universe is computing lots of things all the time: Galaxies, moons, photons, and ferrets.
Basically, when you throw a ball across an empty room, the ball visits many different states via a set of functions known as the laws of physics. The universe used your input of winding up your arm and angle at which the ball was thrown, and computed the output trajectory of states. It is important to note that in this example, the laws of physics affecting the ball remain constant, and only the states are changing.
Living systems are well-known to be out of equilibrium. If we were to put this in terms of states, functions, and computations, we could say something like “life is an unlikely state of the universe and unlikely functions got us there.” In other words, life seems like an unlikely computation. Life is an unlikely trajectory of states and yet, some functions got us here.
What were these functions and what did they look like?
Statistical physics already uses this kind of description to determine things like temperature and entropy. Many scientists are already working to understand how to move from one state to another, and how this might relate to biology.
Jeremy England was recently in the media for his statistical physics-based view of biological systems. He shows how moving towards unlikely states is easy given the correct context. Since biology seems to be a bunch of unlikely states in the universe, we can use this formalism to show that maybe these states were actually very likely in context of our planet.
Sara Walker looks at how information has causal power over a system. Stated another way, this is how programs (things that control which states and functions a system uses) look like under a microscope. In our laptops, computers use programs like Windows 10. But what does Windows 10 look like on a microchip? If we understand how causality, controllability, and information relate to each other, then we can understand how life moves from one state to another. If we understand how systems process information, then we will be many steps closer to understanding what life is, and how it might have emerged from non-life.
So can we twist and intertwine physical laws to tell us what life is and how it emerged? I think so. We simply need to redefine the universe in a way that we can write old physics in new equations. Then maybe someday, we can watch the universe compute life, and maybe watch it compute life elsewhere… or even compute life ourselves.