Why are some people even questioning that we have free will? Isn‘t it, like the great French philosopher René Descartes argued, simply self-evident that our will is free? Isn’t it absurd to believe, we do not make real decisions, given the fact how we struggle to make them every day? Clearly, you are able to freely choose to eat an apple or a banana, and no one in the world could predict, with certainty, which way your decision will manifest.

But a decision may just seem unpredictable to us, because human brains are so incredibly complicated. If an apple falls from a tree, we can calculate its movement, as the laws of physics that apply to the fruit are relatively simple. A brain consists of around 90 billion neurons that are interconnected in complex ways. Additionally each neuron is a complicated biological machine in itself. Because of this tremendous complexity, we cannot calculate behavior that results from the computations of the brain.

The French mathematician Pierre-Simon Laplace introduced the idea of an entity called Laplace‘s Demon. This hypothetical, omniscient being knows everything that can be known about the universe, including every detail of the inner workings of my physical brain. Some argue because he possesses knowledge of all neurological processes, this demon would be able to predict my behavior with absolute certainty. This worldview, that the future of the universe is fully determined by its past, through the laws of cause and effect, was held by many famous thinkers such as Bertrand Russell, Voltaire, Charles Darwin and Albert Einstein.

La Place's demon

Laplace’s demon; not always using his powers for good.

The argument basically goes like this:

  • Our consciousness is fully determined by the physical processes of our brains.
  • All physical processes can be calculated and predicted, given I have all the necessary information.
  • That means consciousness can be calculated, and thus, it cannot be free.

There are more than enough philosophical discussions about this problem and most leave you even more confused than you were before. So let’s not do that. Instead let’s have a look if our advanced understanding of physics can help us answering the question: “Do we have free will?”


Physics and Free Will

Our bodies exist in space and in time. We do not know with absolute certainty whether our consciousness exists in the realm of space. But we know that consciousness exists in the domain of time. Our mind travels through time just like our physical body does. Therefore the mind has to adhere to the rules of time, according to physics.

Until the early 1920s, time was believed to progress at a fixed rate in all the universe, no matter where you are. Then Einstein came along and realized: Time is not a label of the whole universe. Time is experienced locally.

Imagine two events happening in two different locations, that occur simultaneously in the reference frame of one inertial observer. Einstein showed that those two events may occur non-simultaneously in the reference frame of another inertial observer. This is called ‘lack of absolute simultaneity’.

local now


The figure above is an oversimplification, since, to get the full picture, we have to take motion into account. A good explanation of this can be viewed in Brian Greene’s show “The Fabric of the Cosmos” about time:

Einstein’s theory shows that the past is not gone. It is just gone for us. At some parts of the universe our past is still to be observed. Also our future is not yet to be happen. It already happened somewhere in the universe. It just needs some time to get to our position, for us to be experienced. Past, present and future are all equally real, they all exist. They exist in something we call space-time. This space-time includes all reality, all space at all times. Future, past and now.

Tegmark Quote


Well, if this is true, it seems like it’s “Game Over” for Free Will. If the future already exist, I cannot decide differently. If there are no alternative possibilities for me to decide upon, I do not have free will, right?

The argument is sound, but Einstein’s relativity theory does not describe all reality. The micro-nature of the cosmos is expressed by something even weirder: Quantum Physics.

The non-existence of free will is only true if our 4-Dimensional reality, that we call space-time, is static and not able to change. Yet there is a mysterious phenomenon called “quantum entanglement” that suggests that reality is not accurately represented by a static 4D block.

Quantum entanglement refers to the phenomenon of particles to affect each other without any time passing, regardless of distance. This is not just a “freak property” that appears for some particles in a lab. It seems to be an intrinsic property of the universe. When several particles are entangled, they form a composite system in which they cannot be described independently from each other. This is known as ‘nonlocality’. Measuring one particle immediately affects all the other entangled particles. The crucial part here is that they affect each other instantaneously. Which means that some information must be either traveling faster than light, or taking a shortcut through a dimension outside of space-time.

Recently, scientists at the National Institute of Standard and Technology (NIST) have proven beyond reasonable doubt that ‘nonlocality’ is actually real.1



If some information can travel faster than light, it opens the possibility for the future to affect the past. A future that is able to affect the past (at least on the quantum level) does not paint a picture of space-time that is static. It depicts a space-time that is able to change, in some way, constantly.

But how can space-time change? Traditionally things change over time, which is not possible in this case, as time (together with space) is the very thing that changes. So what is that thing outside space time? Another dimension? We don’t know for sure. All we know is that there must be something more to reality than the 4-dimensional space-time continuum.

If we combine the insights from relativity and quantum dynamics, we might conclude that past, present and future are already written; but the ink is not yet dry.

The Swiss physicists Nicolas Gisin and Antoine Suarez think that nonlocality can explain free will, because “something is coming from outside space and time”. Since we know almost nothing about this mysterious thing, we cannot make any statements about whether determinism applies to it or not. It might be that free will, if it exists, originates from this mysterious realm without being determined by something else. It seems as free will, much like god or other spiritual claims, is a matter of believe.

Do I personally believe that we have free will?

If I perform a deep introspection on the inner workings of my mind, I have to agree with Bertrand Russell who said: “I cannot find any specific occurrence in my mind that I could call ‘will’.” A free will, to me, sounds like ‘something’ (a decision, or at least some part of a decision) is created out of ‘nothing’. This, to me, sounds impossible due to the fundamental property of the universe that energy cannot be created out of nothing, which is true even in the quantum world.

So let’s assume we don’t have free will. Does this mean we have to concede into an existential crisis? That our lives have no meaning and we might as well just shoot ourselves?

Not necessarily. Even if I don’t believe in free will, I treat it just like I treat the fact that the universe has a diameter of at least 93 billion light years. If I would be consciously aware of this fact all the time, it would make me feel incredibly tiny and insignificant. I couldn’t solve the tasks of my everyday life. So what I do is, I ponder about the universe a bit and then I come back to my human life and focus on the tasks and relationships that have meaning for me, leaving the universe at the doorsteps.



Shalm, L. K., Meyer-Scott, E., Christensen, B. G., Bierhorst, P., Wayne, M. A., Stevens, M. J., … & Nam, S. W. (2015). A strong loophole-free test of local realism. arXiv preprint arXiv:1511.03189.