Does Free Will Exist?: A Physics Perspective

Updated: Feb 15

Reductionism vs. Emergentism

Let's start with a simpler question, does temperature exist? This question may strike you as ridiculous, of course temperature exists! And so it should, temperature is an entity we are very familiar with and has very real consequences for our day to day living, much like free will.

As far as a physicist is concerned, temperature is a concept from thermodynamics, the science of heat and steam engines. Thermodynamics was wildly successful at describing the behavior of steam engines, and other entities in the macroscopic (large, slow moving) world. Albert Einstein once said that thermodynamics “is the only physical theory of universal content which I am convinced will never be overthrown”. The pioneers of thermodynamics were a practical bunch who didn’t concern themselves, or more accurately lived in a time before the atom reigned supreme, with what was happening under the hood, what atomic behavior gave rise to thermodynamic concepts such as temperature and entropy (disorder).

In the late 19th century, a luminary named Ludwig Boltzman started peeling back the layers and looking under the hood. He showed that the key thermodynamic principle of entropy, the state of order/disorder in a system, could be explained entirely by the behavior of the atoms of that system whizzing around, doing what atoms do. Likewise, temperature was explainable entirely in terms of how much the atoms were moving. More movement, more energy transferred to your skin, less need for pants. This process of looking under the hood, describing macroscopic observations and experiences in terms of underlying, in the case atomic, determinants, is referred to as reductionism, which will rear its head later. Boltzman’s ideas were ahead of his time, and angrily rejected by his peers and societal elites, Boltzman’s mental condition deteriorated and he hung himself whilst on vacation in Austria.

Back to steam engines, no 19th century engineer in their right mind would try to predict or explain what a steam engine is going to do in terms of the motion of atoms. It would take an extraordinary amount of computing power and complexity, and even if you could do it, the results would be just numbers on a page, without meaning or real understanding of the forces driving the steam engine. Thermodynamics and temperature on the other hand were simple, elegant concepts which accurately described the behaviour of the steam engine and gave insight into the processes making things tick. Energy flows from higher temperature to lower temperature, burning some coal will raise the temperature, increase the pressure, push a piston, and send you on your way from London to Liverpool.

So it is beyond question that temperature is a useful concept, with high explanatory power and yielding insight into processes which give rise to what we see. So at this juncture I encourage you to ask yourself, does the fact that temperature can be explained in terms of atomic behavior mean that temperature isn’t real? Does the fact that temperature is an emergent phenomena (something that arises from the behavior of a vast number of interacting underlying entities, in this case atoms) mean that temperature just exists in our heads as a useful concept, but whats really going on is simply atoms whizzing around? I imagine in this case the answer is either “who cares?” or “temperature exists at the macroscopic scale and atoms exist at the microscopic scale[1]”. No contradiction or need for further thought.

So why this detour to thermodynamics. Later I will argue that another emergent phenomena, free will, is much the same as temperature, and the fact that it may one day be reduced to the behviour of neurons, neurotransmitters and electricity, in no way diminishes its existence or reality. I will return to reductionalism later, but for now, I must introduce two new concepts from the wacky world of physics.

Duality and Frames of Reference

Whether free will exists or not really depends entirely on how you look at it. To illustrate the point I use a couple of analogies and principles from physics, duality and frames of references. The first is from quantum mechanics, the strange phenomena of wave/particle duality. Now when someone purporting to make a philosophical point appeals to quantum mechanics, they are almost invariably taking liberties with how physicists interpret quantum mechanical peculiarities, and should be viewed with great suspicion. I hope to avoid such suspicion of myself by telling you that I used to be a quantum physicist and I use quantum mechanics solely as an analogy to illustrate a way of thinking, not to prove anything about the human realm. Tiny particles behave very differently to large objects. They travel as waves, but when you measure them, they collapse into a single point, a particle. When we ask the question "so what is an electron, is it a wave or a particle?", the best answer we can give is, "It's both, depends what property of the electron you are talking about."

The second analogy, and the one I will be carrying forward is that of electromagnetism. We're all familiar with electric currents running through wires to turn on light bulbs and power our iPhones, and with magnetic fields which allow us to attach funky travel souvenirs to our fridges. These two phenomena were thought separate until a Scottish gentleman named James Clarke Maxwell came along and showed that what appears to be an electric field to one observer, may appear to be a magnetic field to a second observer moving relative to the first, what is known as the frame of reference. Now these examples from physics are just analogies serving to make you comfortable with the idea that a physical entity can be two things at once, depending on the way you look at it, or the property of the thing you are interested in. Now I introduce two frames of reference through which we will view free will. These two frames give different answers to the question does free will exist? Yet they are not contradictory, they are simply two sides of the same coin. And as the examples from physics demonstrate, if you're not comfortable with two seemingly contradictory propositions being both true, then you're living in the wrong universe. The two frames of reference I am will use to address free will are the material world and the world of meaning. For an excellent description of these two worlds I recommend the book "I am a Strange Loop" by Douglas Hoffstader. In brief, the world of meaning is the world of Shakespeare and Sartre. The players in the game interpret material events in terms of their pre-existing concepts of the world and act accordingly. I would also include mathematics in the world of meaning. Mathematical entities do not have a material basis, they are concepts which live I their own universe but can be used to represent occurances in the material world. There are “laws” in mathematics, and there are “laws” governing the actions of man, albeit not always strictly adhered to. The material world is the world of matter obeying the laws of physics. According to Isaac Newton, this world is deterministic (knowing the initial conditions means you can predict all future conditions), but according to quantum mechanics this world is probabilistic (knowing the initial conditions means you can predict the probability of all future conditions, but not the exact ones which will come to pass. Like the outcome of rolling a dice).

Now you may have noticed I've framed physical reality in terms of prediction. Some philosophers frame the question of free will entirely in terms of prediction, which I object to but we’ll roll with it for now. If it can be predicted what a human will do, then they weren't really choosing that action, it was preordained and they were following their programing. Now as far as neuroscience goes, we are learning more every day about what makes the brain tick and gives rise to behaviour. The famous "readiness potential" experiment can detect brain waves indicating that a person is about to take an action, before the person themselves has consciously decided to take an action. Although it cannot yet be said that neuroscience has shown that free will does not exist, and that its all just cogs turning in the head, it seems only a matter of time and technology before we can predict what a human will do before they themselves are (consciously) aware of what they will do. So is free will dead? Probably, in the material world. Now let me take you to a different world, the world of meaning.

Materialism vs. Metaphysical Dualism

Why did Henry VIII divorce Catherine of Aragon? A hardcore materialist (those who believe that only matter-energy, and mindless forces of nature and space-time exist) would say that a group of neurons in his emotional limbic system released some neurotransmitters to communicate with neurons in his decision making frontal cortex resulting in a behaviour which eventually ended in priests in England being allowed to get down and dirty with their wives. But this reductionalist/materialistic explanation hardly addresses the question at all. Its is the wrong level of description, much like atoms are the wrong level of description to describe steam engines, and we’re better off appealing to temperature and entropy. Henry VII divorced Cathrine of Aragon because he wanted a son to succeed him, and the Spanish princess had not delivered (fortunately for Catherine, being a Spanish princess meant she avoided Henry's later choppy-choppy approach to conjugal separation). The laws governing Henry’s behavior came from the world of meaning, not the world of matter. Now, Henry's wanting a son may one day be entirely describable in terms of neuronal networks, genes and spermicles. But I reject the proposal that this would mean that Henry's desires were irrelevant and simply the result of preordained atomic behaviour. To explain why, we must look at the interaction between the material world and the world of meaning.

The materialist would either reject outright the world of meaning, or acknowledge its existance but declare it secondary, since with sufficient knowledge and technology, we could describe it in terms of the underlying material world. This is a one way direction of influence whereby the material world determines the world of meaning, and not vice-versa. But a simple thought experiment would suggest that this uni-directionality is far from clear-cut.

Imagine a set of dominoes which have been set up by a wiley mathematician, who lives in the world of meaning. Or if you disagree that mathematics exists in the world of meaning then lets replace her with an artist drawing happy and sad faces. These set of dominoes are set up such that at the beginning of the structure is a hammer which pushes the first domino with a direction dependent on a number input by the mathematician or a face drawn by the artist. At the end of the cascade, there are two rows, and at the end of each row is a single domino whose actions we seek to understand. Now the wiley mathematician/artist has set up the dominoes such that the left column domino will fall if the number input is prime (divisible only by itself or 1), or the face is happy, and the right column domino will fall if the number is non-prime, or the face is sad. If you doubt the feasibility of such a set up, I refer you to computational neural networks which by adjusting the weights of connections can learn to give a binary output indicating a happy or sad face, or a prime and non-prime number. The physical basis of a computational neural network are electrons and circuit boards, but could just as easily be dominoes (in principle, not in practice, lol).

To be continued……

[1] Slight aside, atoms themselves are merely concepts we use to describe observations, they are themselves explicable in terms of “simpler” entities. Some physicists believe that the fundamental building blocks of matter are multidimensional buzzing strings.


©2020 by Ben Sinclair.