Epistemic status: thought experiment

Spoiler Warning: The setup of the thought experiment comes from “Star Maker” by Olaf Stapledon. If you intend to read the book, I recommend not reading this post.

I

Imagine a universe where stars are conscious beings. Their insides are made of a dynamic network of plasma that supports advanced cognitive functions. Each star gives rise to one unified self, similarly to how a human body gives rise to a unified sense of self (psychological disorders aside), but with a body of astronomical proportions.

Stars are able to perceive the composition of their star-body and their galactic environment, recognizing the presence of nearby astronomical objects like planets orbiting around them and other stars in their neighborhood. They communicate with each other, changing their inner plasma currents to emit modulations of magnetic fields that travel across light-years.

Over billions of years, stars build advanced science. They derived the equivalent of Einstein’s general relativity theory. Using these equations, they are able to perfectly predict their motion through space. They know exactly to which corner of the cosmos they are headed.

This science imbued their psychology in an interesting way. Their sense of free will aligns with the trajectory the equations predict. They feel like they want to move in the direction the equations predict, even though they have no propulsion methods that could significantly influence their path. Every star feels part of a giant cosmic dance. Each year, as they see themselves moving in exactly the right direction, they experience a profound satisfaction in choosing to honor the cosmos.

Sometimes, because of chaotic plasma dynamics, stars make mistakes in their predicted trajectory. They want to go a certain way, but what they see unfolding doesn’t conform. These stars become distressed, feeling like their desires are constantly negated, and they fall into deep depression.

II

Human bodies are not that different from stars. They are also structures of atoms that obey the laws of physics. Their trajectory cannot be predicted by equations as simple as general relativity, but they could certainly be described by equations in theory, potentially using probability distributions because of quantum uncertainties.

Here is the punchline: our sense of free will, our sense of what we want to do, is similarly misguided as the stars’ cosmos dance.

One might argue that there is a crucial difference: contrary to the stars, we have muscles, a causal path for our cognitive processes to influence our movements. However, our brain is also ruled by the laws of physics. It is simply a more complex system than star dynamics. The sensation of free will is an emergent phenomenon from the brain’s mechanics that determines movement. Free will is what it feels like to mechanically unfold events, but the sensation is downstream of the causal chain. By removing the option for self-propulsion, the analogy makes this point clearer.

I feel like I want to reach out to grab this glass of water in front of me, but really, the laws of physics make me grasp for the glass. Internally, my unconscious crafted the feeling of wanting to perform the very same action to match the movements and avoid becoming insane.

To cope with our incapacity to influence our actions outside of the laws of physics, we craft our desires to align with what we would do anyway. If we want anything else, we are bound to become distressed by observing how the cold laws of physics, indifferent to our inner wants, will push us away from the actions we intended. It’s the body-mind dissociation that occurs in some psychological disorders: I try to command my arms to move, but they stay still, and conversely, I see my hand moving without having any intention to do so.

Our only option is the same as that of the stars: to create a will that matches our natural trajectory.

III

This story is a standard argument for why the determinism of the laws of physics is incompatible with free will.

However, the thought experiment opens a way to go beyond this intermediate conclusion in an elegant way. There is one crucial difference between stars and humans that reconciles free will and physical determinism.

I encourage you, dear reader, to stop for a moment and try to find the flaw. What is the difference between humans and stars that makes the parallel invalid?

A picture to leave you time to think. Trails from the movements of stars 400,000 years in the future seen from Earth's sky. Source.

IV

Contrary to the determinist argument, the lack of a causal path for internal processes to influence the trajectory does matter.

The internal monologue (and the unconscious processes shaping the monologue) that occurs in one’s head before deciding to take action 1 or action 2 is part of the causal path deciding between action 1 or action 2. This doesn’t mean that the brain starts a causal chain out of thin air; it is still a physical system that obeys the laws of physics.

The important piece is that the brain acts as a bottleneck in the causal chains between the information received by the senses and the actions taken. To predict the (deterministic) output of the deliberation between action 1 and action 2, one would need to simulate the integration of information occurring over a lifetime to form the current neural connections, as well as the complex neural dynamics at play in the given deliberation.

And, well, this is a pretty complex system. In general, there is no easier way to know which action a person will take than to wait, let the brain dynamics unfold over time, allow the person to ponder, and see what they decide.

The stars from the intro story also have a complex internal system made of plasma dynamics. However, the causal chains unfolding within the stars have no way to escape beyond communication with other stars. Contrary to humans, their mental processes are irrelevant for predicting their movements.

V

We established that the complexity of mental processes is part of the causal chain leading to actions. For instance, the inner monologue associated with deliberation is linked with mental processes that are causally upstream of actions.

Note that we didn’t say anything about the connection between the inner monologue and the mental processes. This would touch on the hard problem of consciousness, which we can safely avoid for the purpose of this argument.

Moreover, this doesn’t mean that one can “exert willpower” to make decisions. The form of the causal chain is complex, and our feeling of “exerting willpower” might have nothing to do with the causal chains at play in the decision. I recommend Steven Byrnes’ sequences on Intuitive Self Models to clarify intuitions on free will, and in particular his concise point on free will and determinism that summarizes the position I describe here.

Important influences can also happen outside of the decision-maker’s body. For instance, one could be manipulated by an adversary selecting the information received to deliberate in a certain way and reach a specific conclusion.

Finally, I found this story useful as a guide to making effective decisions. When deliberating, I ask myself: How predictable is my decision from i) what I thought one hour ago or ii) simple outside variables? Which observations or arguments changed my mind, or which alternative observations would change my mind? I found these questions helpful to estimate how productive is my inner deliberation process.

So, the next time you have to make a choice, you can ask yourself, “how much of a star am I?” to see if you are taking a real decision.