This is Part 4 in a series on the physics of free will. Check out Parts 1, 2, and 3.
But we’re not going for one thing or another, are we? We’re here to explore ideas – that’s most of the fun anyway. And there’s one more aspect of physics that takes part in the free will discussion, and that’s the concept of emergence.
So, we have all these really fun and cool theories of physics. We have electromagnetism. We have quantum field theory. We have the Navier-Stokes equation. And they’re all really good and really powerful and tell us how very particular systems will evolve with time. They tell us the history of the universe, or our weekend weather outlook, or what kinds of weird subatomic particles will come out when we smash stuff together really hard.
But there’s more to life – and life in the universe – than these laws. And just because you can write down a law that describes one phenomenon in one domain, it doesn’t mean that you can automatically predict how other, larger, more complex systems will behave.
But sometimes you can. Like temperature. A single particle doesn’t have a temperature. It has a position and a velocity. But if you get zillions of particles together, all of a sudden you get a new property of the whole system: the temperature of a box of particles. Temperature EMERGES from the individual motions of the particles, even though each individual particle has no idea what the heck you’re talking about when you bring up temperature.
We actually have a way of connecting the microscopic properties of particles with the macroscopic emergent behavior, and that’s through statistical mechanics which is beyond amazing and also sadly not the subject of today’s episode.
But statistical mechanics is an exception, not a rule. Let me take an opposite extreme: emotions. We all know that emotions have a physiological component. There are chemical and hormonal and physical changes that happen inside your body and brain when you experience, say, sadness or joy.
Technically, if we boil everything down, it’s all just a bunch of subatomic particles whizzing around. And we have a powerful theory of describing how subatomic particles behave, and that’s quantum field theory. So it SHOULD be true in a deterministic universe that you can start with QFT and do enough work to eventually describe all the stuff happening in your brain and body when you get sad.
Except we don’t. Even worse, we CAN’T. Emotions are an EMERGENT property of the human body/brain system. There is NO theory of physics that can describe the appearance of emotions based on fundamental principles. Even if we knew all the physics there was to know in the entire cosmos, and we ourselves became Laplace’s Demons, then we STILL couldn’t use those fundamental physics to make predictions, because emergence breaks the connection between fundamental microscopic behaviors are macroscopic manifestations.
And it’s in this language of emergence that there might be a way to preserve free will in a deterministic universe. Most philosophers align with some shade of thought called compatibilism, which states that free will as we understanding it (the freedom to make choices that are not caused or forced) with causal determinism.
I mean, let’s say I give you a choice. Do you want a slice of French mimolette or, I don’t know, a lovely Italian scamorza. Either of those choices is compatible with all known laws of physics and determinism. Once you make the choice the universe sets in motion and all else follows. The only thing we are worrying about is the choice itself, so maybe – big maybe here – there is some law of physics that we have not yet discovered that PERMITS free will, even in a deterministic universe. And the only reason this appears mysterious to us is that we have not yet advanced enough in our physics to make that kind of connection.
One of my favorite books of all time is Godel, Escher, Bach by Douglas Hofstadter. In the book he shows examples from music, art, and mathematics to show how simple meaningless elements, when repeated in certain ways, can give rise to exceptionally meaningful, complex systems. He proposes this as a way to understand consciousness: that there are rules that the universe obeys that can give rise to things like free will. Where you can have your metaphysical cake and eat it too.
We just have to keep our minds open to the choices the universe offers us.
That was another free will joke, by the way.
