Free Will and Determinism

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Metaphysical Considerations


These notes are intended to highlight some of the metaphysical problems surrounding the area of free will and determinism. It traces these metaphysical issues through the history of philosophy and science. Although ethical and theological considerations may be mentioned in passing they are not looked at in any depth – that is for later.

Greek Thought

The early Greek philosophers were divided over the existence of free will. The Pythagoreans (c.5th cent. BCE) saw its existence as being a prerequisite for moral accountability. Likewise Socrates (c.470-399 BCE) and Plato (c.428-347 BCE) were keen to emphasise the moral consequences of all philosophical problems. Aristotle also believed that a person is ultimately responsible for their actions and as such the future could not be predicted.

The early Greek atomists such as Democritus (c.460-370 BCE) and Leucippus (c. 5th cent. BCE) were the first to see the universe as being purely mechanicalistic. The one surviving quote from Leucippus’s work asserts a universal determinism: “Nothing happens at random, but everything from rational principle and of necessity.”

Epicurus (c.341-270 BCE) although a materialist and an atomist, did not believe that determinism naturally followed. Unlike Democritus and Leucippus he did not believe that these atoms were entirely governed by natural laws. On their ‘downward paths’, atoms could swerve, activated by something akin to free will. Epicurius was probably motivated by the natural consequences of the atomists’ determinism which was fatalism.

The Enlightenment

The concept of ‘cause and effect’ was to form the bedrock of the empiricists of the Enlightenment who looked for ways of grounding the newly discovered science. Newton (1642-1727) asserted that an object remains at rest until it is acted upon by a force. The French physicists and mathematician, Pierre-Simon Laplace (1749-1827) was the first to point out the consequences of Newtonian physics. He proposed that if a powerful intellect (viz. Laplace’s demon) possessed an understanding of Newton’s laws, and had a description of the current position and momentum of each particle in the universe and the necessary mathematical ability, that it was possible to predict every event that has and will take place in the universe.


Descartes (1569-1650) believed that living organisms, just as much as dead matter, were governed by the laws of physics. He thought of animals as machines, analogous to clocks. The Cartesian material world was rigidly deterministic. However, Descartes permitted one exception. He contended that a human soul could, by an act of the will change the direction if not the magnitude of the motion of its life. Unfortunately this concession to human free will seems to be at odds with his laws of mechanics. It seems wholly reasonable to extend his treatment of animals to human beings. Descartes is left with an unresolved dualism.


Having strong ethical views which emphasise a person’s duty, it is not surprising that Kant (1724-1804) vigorously defended the concept of free will. However, Kant equally wanted to defend the idea of universality applying to the laws of nature. This universality naturally leans towards determinism. The two appear to be irreconcilable. Kant’s solution can be found in his division of reality into phenomena and noumena. The deterministic world of nature as it appears to us, belongs to the realm of phenomena. Our thoughts and actions are subject to the category of causality. Everything that belongs to the world of experience is governed by the laws of nature. Our actions then are determined. A prerequisite of Kant’s deontological ethics is that an individual is free to choose. Kant overcomes this by insisting that determinism only belongs in the phenomenal world. The Ding an sich (thing in itself) remains free, as the laws of causality do not belong in the realm of noumena. The noumena is only discovered through pure reason. Unfortunately there appears to be a major flaw in Kant’s solution. The way we perceive others and their actions can only be known through the phenomena which we have to acknowledge as being determined.

Modern Science

This picture of a clockwork universe has persisted in science until modern times. Only with the advent of quantum physics has the old Newtonian universe been challenged. Some scientists and philosophers alike see quantum physics as the way out for a purely deterministic universe. Likewise, Gregory Mulhauser’s early ‘zany’ notion that Chaos theory might be the means of explaining free will, might not be the non-deterministic solution he had been hoping for (Mulhauser,1998, xvii). Chaos theory states that the unpredictability of a chaotic system, such as the weather, is not due to any lack of governing laws but to the fact that the system is sensitive to minute, immeasurable variations in the initial condition. Famously the hypothesis is that a butterfly flapping its wings may cause a tidal wave on the other side of the world.

It could be argued that modern science has only strengthened the determinist’s position. The recent completion of the human genome project caused much discussion throughout not only the scientific community but also among philosophers, theologians and ethicists. At the centre of the debate was the claim that within a few years scientists would be able to identify genes that were directly responsible for a person’s behaviour. The idea of being able to pin point a gene responsible for one’s sexual orientation or disposition to commit crimes seemed abhorrent for those wanting to defend freedom of choice in such matters.

Roger Penrose sees quantum physics as the possible answer scientists have been looking for in explaining the very mystery of vitalism itself within the universe.

Penrose proposed that human thought, although rationally sound, is not necessarily algorithmic. His conclusion that thought was non-computational was based on Gödel’s theorem that states that there is no consistent formal system in which every mathematical truth is provable. Penrose held that the only non-computational process in the universe was the randomness of quantum mechanics. According to Penrose, the current scientific theories are simply inadequate in their explanation of the non-algorithmic nature of quantum mechanics. He proposed that at the cellular level, the microtubules of the cells of the brain were sensitive to quantum gravity. The link between conscious thought and quantum mechanics is made in the neurons, which are responsible for cognition and consciousness. The conclusion is that ‘microtubules, because they have one foot in quantum mechanics and the other in conscious thought, provide a window for non-algorithmicity in human cognition.’ (Grush)

With the possibility that quantum effects might indeed trigger much larger activities within the brain, some people have expressed the hope that, in such circumstances, quantum indeterminacy might be what provides an opening for the mind to influence the physical brain. Here, a dualist viewpoint would be likely to be adopted, either explicitly or implicitly. Perhaps the ‘free will’ of an ‘external mind’ might be able to influence the quantum choices that actually result from such non-deterministic processes.

(Penrose,1994, p.349)

Einstein warned that far from getting rid of a deterministic universe, quantum mechanics may only affirm it. On a quantum level, all that has changed is the fact that the universe has become more difficult to predict.

Is it possible to test to see if free will exists?

A test to see whether or not someone is governed by free will or determinism would require considering the following condition: would the subject’s behaviour in a given situation have been any different if the subject had so willed it? Those advocating free will would have to reply in the affirmative where as the determinists would have to disagree. However, the main problem with such a test is that there is no real way of validating it. Whatever results are procured from such a test there is no real way of knowing if the results would have been any different. There is no way of knowing whether or not a person’s behaviour in a particular situation would have been any different if they had willed it. As the America philosopher and psychologist, William James (1842-1910), puts it, “the fact is that the question of free will is insoluble on strictly psychological grounds” (Eysenck, 1994, p.66).

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