Free Will an Illusion? Quantum Mechanics Might Have The Answer, You Decide…

Part II: Free Will Is NOT an Illusion

Modern science, is a mixture of deterministic and stochastic theories. Quantum mechanics predicts events only in terms of probabilities, casting doubt on whether the universe is deterministic at all. The opposite of determinism is some kind of indeterminism (otherwise called non-determinism) or randomness. In general, we experience our lives as having free will. The future is not yet determined, and we can influence our career, our lives, our future. If we did not acknowledge free will, the whole self-help business would go broke, and the concept of democracy would also be meaningless… The fact that we experience ourselves as having free will is not proof of having free will. It still could be a perfect illusion. So let´s look if we can find evidence to make more substantial statements about free will.

…if there really is some day discovered a formula for all our desires and caprices — that is, an explanation of what they depend upon, by what laws they arise, how they develop, what they are aiming at in one case and in another and so on, that is a real mathematical formula — then, most likely, man will at once cease to feel desire, indeed, he will be certain to. For who would want to choose by rule? Besides, he will at once be transformed from a human being into an organ-stop or something of that sort; for what is a man without desires, without freewill and without choice, if not a stop in an organ?


In 1884 William James proposed a two-stage model for free will. First, there is a `free´ random generation of alternative possibilities. Second, a `willed` adequately determined decisions consistent with character, values, and desires. I think one of the unique capabilities of humans is that we not only randomly generate alternative possibilities but that we also are able to construct alternative possibilities.

The true free-will ain’t a matter of choosing one of many choices…
but of creating variety of options, then deciding the best choice of all.

Toba Beta

As already discussed, there are different theories about time. The theory according to Tegmark, describes time as a branching tree. This theory does not contradict free will. We have choices, and every choice we make causes a new branch on the tree.

To be a god can ultimately become boring and degrading. There’d be reason enough for the invention of free will! A god might wish to escape into sleep and be alive only in the unconscious projections of his dream-creatures.

Frank Herbert

Quantum mechanics could be interpreted as being unpredictable, or acausal. If an indeterministic interpretation of quantum mechanics is correct, you may still object that such indeterminism is limited to microscopic phenomena. This is not always the case: many macroscopic phenomena are based on quantum effects. For instance, some hardware random number generators work by amplifying quantum effects into practically usable signals. A more substantial question is whether quantum mechanics’ indeterminism allows for the traditional idea of free will. However, if a person’s action is only a result of complete quantum randomness, mental processes as experienced do not influence the probabilistic outcomes. According to many interpretations, non-determinism enables free will to exists, while others assert the opposite (because the action was not controllable by the physical being who claims to possess the free will).

Heisenberg Uncertainty Principle

Introduced first in 1927 by the German physicist Werner Heisenberg, the uncertainty principle states that the more precisely the position of a particle is determined, the less precisely its momentum can be predicted from initial conditions, and vice versa.

It can be expressed in its simplest form as follows: One can never know with perfect accuracy both of those two important factors which determine the movement of one of the smallest particles — its position and its velocity. It is impossible to determine accurately both the position and the direction and speed of a particle at the same instant.


To put it simply, if we see an athlete crossing the finish, we cannot know both his position and speed with perfect accuracy at the same time. Or we know his very accurate position, the finish line picture on which we can very accurately determine his position, but we cannot measure his speed. Or we measure his speed very accurately, but then we cannot accurately determine his position at the finish line. It is impossible to know both the speed and position of a single particle at the same time. So in quantum mechanics, nothing can be certain, and we can only describe things in terms of probabilities. But there are counterarguments; while the Heisenberg Uncertainty Principle prohibits the simultaneous measurement of a particle’s position and momentum, such a prohibition does not apply to groups of particles. Single quantum particles behave randomly, and then become subject to this universal law of causality when subsumed within groups.

Many scientists have tried to make determinism and complementarity the basis of conclusions that seem to me weak and dangerous; for instance, they have used Heisenberg’s uncertainty principle to bolster up human free will, though his principle, which applies exclusively to the behavior of electrons and is the direct result of microphysical measurement techniques, has nothing to do with human freedom of choice. It is far safer and wiser that the physicist remain on the solid ground of theoretical physics itself and eschew the shifting sands of philosophic extrapolations.

Louis de Broglie

Collapse of Wave Function

A wave function is a mathematical entity that provides a probability distribution for the outcomes of each possible measurement on a system. Knowledge of the quantum state together with the rules for the system’s evolution in time exhausts all that can be predicted about the system’s behavior.

A common perception of the Copenhagen interpretation is that an important part of it is the `collapse´ of the wave function. In the act of measurement, the wave function of a system can change suddenly and discontinuously. Prior to a measurement, a wave function involves the various probabilities for the different potential outcomes of that measurement. But when the apparatus registers one of those outcomes, no traces of the others linger.

Heisenberg spoke of the wave function as representing available knowledge of a system and did not use the term `collapse´, but instead termed it `reduction´ of the wave function to a new state representing the change in available knowledge which occurs once a particular phenomenon is registered. You can argue that free will is possible because there is an ontological indeterminism in the natural laws, and that the mind is responsible for the wave function collapse of matter, which leads to a choice among the different possibilities for the body.

Schrödinger’s cat, this thought experiment, highlights the implications of accepting uncertainty at the microscopic level on macroscopic objects. A cat is put in a sealed box, with its life or death made dependent on the state of a subatomic particle. Thus a description of the cat during the course of the experiment, having been entangled with the state of a subatomic particle, becomes a `blur´ of `a living and a dead cat.´ But this can’t be accurate because it implies the cat is actually both dead and alive until the box is opened to check on it. But the cat, if it survives, will only remember being alive. Schrödinger resists “so naively accepting as valid a ‘blurred model’ for representing reality.” How can the cat be both alive and dead? The Copenhagen interpretation is that the wave function reflects our knowledge of the system. The wave function means that, once the cat is observed, there is a 50% chance it will be dead and a 50% chance it will be alive. We live in a universe where the very act of observation determines reality itself. While that doesn’t prove free will exists for certain, it does open the door to the possibility that our choices do impact the future.

Of course the introduction of the observer must not be misunderstood to imply that some kind of subjective features are to be brought into the description of nature. The observer has, rather, only the function of registering decisions, i.e., processes in space and time, and it does not matter whether the observer is an apparatus or a human being; but the registration, i.e., the transition from the `possible´ to the `actual,´ is absolutely necessary here and cannot be omitted from the interpretation of quantum theory.


What this means is that we have to take into account the state of the agent up until the time the choice is made and given that state ask if there is a possible world where the agent makes a choice other than the one he or she made. That, then, is what freedom of choice is.

The theory according to Tegmark, describes time as a branching tree. This theory does not contradict free will. We have choices, and every choice we make causes a new branch on the tree. There are probable states that have the same past up until a point, and then a choice is made, and a non-deterministic path is followed. It doesn’t matter if those paths are all `real worlds,´ what matters is that they have different futures, and all interpretations of quantum physics as-is support this idea.

Another consequence of this is that the absence of total determinism in fundamental physics provides some ‘causal slack’ that mental processes at the neurophysiological level can then take advantage of. The inherent indeterminacy of physical systems means that any given arrangement of atoms in your brain right at this second, will not lead, inevitably, to only one possible specific subsequent state of the brain. Instead, multiple future states are possible, meaning multiple future actions are possible. The outcome is not determined merely by the positions of all the atoms, their lower-order properties of energy, charge, mass, and momentum, and the fundamental forces of physics. This also relates to Bell’s inequality or Bell’s theorem, which shows that quantum measurements do work differently than classical ones. In fact, there is no way to show that before you measure particle A, particle B has a definite state except under some very contrived circumstances, and, likewise, how you measure A does affect the state of B even when light has no time to traverse the distance between them before you do the measurements.

If a thing is free to be good it is also free to be bad. And free will is what has made evil possible. Why, then, did God give them free will? Because free will, though it makes evil possible, is also the only thing that makes possible any love or goodness or joy worth having.

C.S. Lewis

If all this is true, and this is the most important point, then you can say that freedom of choice exists because the agent made different choices in different probable realities. Thus, the agent had the power to choose and exercised it.

This is supported by quantum physics because more than one outcome of a choice can occur from a single state of the universe; an agent does have `the power to do otherwise´ which is what free will is. Essentially, quantum mechanics tells us that there are things which we cannot know about the future, things which are not predetermined but happen with some factor of chance or randomness. Although many things in the world may be predicted, everything is not predetermined, and our actions do not unfold mechanically in a manner predetermined since the very moment of the Big Bang. Free will is preserved.

MD, PhD, but still trying to figure out life…

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