top of page

Do we really have “free will” in a world governed by laws of physics?

  • johnny1003
  • Nov 3
  • 2 min read

Jiayu Li

We as human beings are constantly making choices, whether it is deciding what to have for dinner or how to respond to a friend’s text message. The nature of these choices feels authentic, as they are the manifestation of our desires and autonomous will. But is that “will” truly free? Scientists and philosophers have been debating this question for centuries. On one side is the determinist arguing that the future is shaped by the causation of previous events and thus predetermined, while the indeterminist acknowledges the possibility of free will.

 

One of the important pieces of evidence of determinism is Isaac Newton’s classical mechanics. In his 1687 book Principia, he suggested the law of universal gravitation and the three laws of motion. The law of universal gravitation and Newton’s third law defined the forces affecting the objects when they interact, while his first and second laws defined how the objects will behave under the influences of such forces. Under this notion, if we could know the position, velocity, and the forces acting on any entity, we could predict its state at any instance in the future. The universe then becomes like a “clockwork”; once set in motion, the universe runs its course inexorably. The French mathematician built on this idea by suggesting a thought experiment involving a hypothetical demon. The demon has the power to calculate large amounts of information and knows the momentum and position. Thus, it could use Newton’s laws to predict every future event and deduce every past event in the universe. This way, every human action would become predictable and predetermined, as our brains are also made up of particles.

 

However, the deterministic interpretation was challenged as Newtonian mechanics was proven inaccurate by the studies in quantum physics. Heisenberg’s uncertainty suggests that we could never precisely know the position and the momentum of a particle at the same time. Therefore, we could not use that information to predict future states of particles.

 

In the world of quantum mechanics, particles like electrons are superpositions of different states, meaning that they are at different states at the same time. However, the act of observing forces them to collapse into a single state, and that state could be determined only probabilistically using complex functions. Hence, we could never know the certain result until it happens. When the theory is applied to our mind, it brings us the question of whether randomness is the same as freedom. One could argue that if you decided to raise your hand just because there is a random fluctuation in the neuron, you become a puppet of chance.

 

So, does physics disprove free will? The answer is maybe. While classical mechanics suggests free will is just an illusion arising from a deterministic universe, quantum physics gives chances for indeterminism, yet it leaves the question for philosophers whether randomness equates freedom.


Citations:

 

Koch, C. (2012). Finding Free Will. Scientific American Mind, 23(2), 22–27. https://doi.org/10.1038/scientificamericanmind0512-22

 

‌

Hilgevoord, J., & Uffink, J. (2016). The Uncertainty Principle. Stanford Encyclopedia of Philosophy. https://plato.stanford.edu/entries/qt-uncertainty/

‌

Faye, J. (2014). Copenhagen Interpretation of Quantum Mechanics (Stanford Encyclopedia of Philosophy). Stanford.edu. https://plato.stanford.edu/entries/qm-copenhagen/


Comments

bottom of page