The science of the free will

By Ella Knüpling

Civilization as we know it depends on the assumption that all human beings possess a free will. From religions and ethical codes to many legal systems and welfare provision; numerous crucial aspects of modern societies are founded in the widespread belief that people are autonomous agents (Cave, 2016). However, at least since the 18th century, more and more scientists have questioned the existence of the free will, which has initiated one of the most significant debates of human existence. Up to this day, researchers from different science fields disagree on the central question of whether free will exists or not. (Kastrup, 2020; Schwartz, 2013)

But in order to be able to address this question, one needs to consider what is meant precisely by free will. Although a consensus on an exact definition of this term does not exist, a living being can be generally described as having a free will if its decisions are dependent on its “felt volitional states”, preferences, ideas and intentions which the being consciously defines and identifies with (Kastrup, 2020). The free will is thus rooted in a power over one’s own choices, rationally motivated by the current mental state, and the ability to freely decide between alternative possibilities (Lavazza, 2019; O’Connor & Franklin, 2020). In brief, free will can be said to require “conscious control” (Lavazza, 2019). 

The ongoing debate about the existence of this “conscious control” over one’s actions gained attention with 18th century theoretical physicists, who followed the lead of mathematician Pierre-Simon Laplace (1749-1827) in believing that physics could deny free will (Ellis, 2020). These scientists showed that if one knows the initial conditions of the variables of a physical system, together with the equations describing how these variables change over time, one can predict the outcome of that system at any timepoint in the future (Lavazza, 2019). For example, if the starting positions and velocities of all the particles in a gas container are known, physical equations can predict the positions and velocities of all these particles at all later times (Ellis, 2020). The laws of physics, the theoretical physicists argued, do not allow any system to deviate from such a predicted trajectory (Lavazza, 2019; O’Connor & Franklin, 2020).

Following this theory and noticing that everything on earth, from cells to entire organisms, is made up of physical particles, namely protons, electrons and neutrons, the 18th century theoretical physicists also described the world as a system with a physically predictable path. In this view, a person’s decisions, originating in the brain as movements of physical entities, were thus predetermined at the beginning of the Universe, based on the states of the particles at that time. In this so-called determinism, there is therefore no room for free will. (Ellis, 2020; Lavazza, 2019) 

Physical determinism has always been an exceptionally influential threat to the idea of free will, and it still is (Lavazza, 2019). However, arguments against it are arising, one of which is based on a different branch of physics; the quantum theory. As a result of the uncertainty principle which is fundamental to quantum physics, the time evolution of the configuration of physical systems cannot be calculated with infinite accuracy. This apparent randomness in quantum results might seem to contradict the concept of the world following an exact, predictable path and could therefore create a possibility for some sort of free will. But as many physicists believe that quantum uncertainty is not true randomness, this argument against determinism and for free will is controversial. (Koberlein, 2018)

A different way around the deterministic worldview of many physicists might be made possible by biochemistry. Following some biochemists, determinists ignore the fact that the state of a physical system at a specific timepoint does not only depend on the physical equations and initial values, but also on the varying constraints presented to the system over time. In the case of the system that is life, whose functioning is enabled by biomolecules like proteins, the changing shapes, or conformations, of these biomolecules behave like constraints that have an effect on the behaviour of the system. In neurons, for example, proteins called ion channels, which sit in the plasma membrane, act like molecular gates; their conformation, which can be either closed or open, determines whether ions are allowed to flow in and out of the neurons. As this movement of ions in neurons initiates electric nerve impulses by which organisms think, the shapes of the ion channels can be seen as constraints which control brain functioning. (Ellis, 2020)

The shape of such a channel and thus the constraint it forms on the process of thinking at a specific time point can be affected by a variety of biochemical processes, like the binding of a signalling molecule to the channel (Ellis, 2020). The processes which drive conformational changes arise from an immense molecular disorder, as in and around all cells millions to billions of molecules collide every second (Noble & Noble, 2018). Some biochemists argue that the specific constraints which emerge out of this cellular chaos could never be calculated from the initial data of the enormous number of physical particles in a cell (Ellis, 2020; Rovelli, 2013). In this view, brain cells deliberately maintain physical stochasticity, which can be pushed towards order, like a specific shape of a molecular gate, and thus towards a choice, by active, higher level mental operations, like emotions and preferences, not describable through physics (Noble & Noble, 2018). This would mean that, although the initial data and the equations of the particles which enable thinking are physically determined, constraints on thinking are not and decisions are therefore made with a free will (Ellis, 2020).

The thought that free will is not reducible to physics but can only be explained by higher-level phenomena is, although in a slightly modified form, shared by some philosophers. They conclude that the entirety of the world is so complex, that its characteristics are not just a sum of the features of its building blocks, the physical particles, but more than that. Physicists, they say, make the mistake of looking for free will at the wrong level, the level of the particles. (Talbert, 2019)

Many psychologists and neuroscientists have taken a different approach to the question of the free will; they measured the electrical activity in a person’s brain while an act, like tapping a finger, was set into motion by that person (Cave, 2016; Lavazza, 2019). According to the now-famous Benjamin Libet, these experiments showed that the electrical signals which initiate an action at the level of the brain build up before the person consciously makes the decision to act (Libet et al., 1983). This would mean that conscious intentions are only misleading afterthoughts and do not play any causal role in the generation of an action, which is a widespread theory called epiphenomenalism (Gholipour, 2019; Lavazza, 2019). Following epiphenomenalists, as actions do not come from active decision-making, they are not free (Lavazza, 2019).

However, the reliability of Libet’s experiments has been challenged in more recent years by different researchers (Lavazza, 2019). Some question whether the electrical signals in the brains of Libet’s participants, which preceded their conscious experience of deciding, really caused their actions (Gholipour, 2019). Additionally, there is a controversial interpretation of the moment in which conscious decision-making takes place and in the way in which this moment was determined by Libet (Lavazza, 2019). Epiphenomenalism therefore does not seem a conclusive argument against free will anymore. 

Finally, there are different biological viewpoints on free will. Many biologists assume that a great part of a person’s actions follow necessarily from this person’s genetics (Baggini, 2015; Mitchell, 2019). Others argue that there is an unconscious influence of environmental stimuli on the choices of a person (Cave, 2016; Lavazza, 2019). However, although much evidence has been found for both of these theories, numerous biologists still find it improbable that all complex psychological processes are entirely predetermined (Baggini, 2015; Lavazza, 2019; Mitchell, 2019). Additionally, controversy exists about the apparent absence of an evolutionary advantage of consciousness and thinking, if these processes do not have an effect on a person’s actions (Cave, 2016). Many therefore conclude that free will comes in degrees, depending on the situation (Baggini, 2015; Lavazza, 2019). 

The conclusions from different science fields thus continue to vary and, as none of the described and other existing arguments seems to be convincing enough, the central debate on whether humans have a free will or not is still not settled. However, regardless of what the ultimate answer to this debate may be, an abandonment of the free will might lead to unwanted consequences (Cave, 2016). Given the facts that experiments have shown that people act less responsibly if their idea of the free will is weakened (Vohs & Baumeister, 2009) and that the issue is fundamental to the human view of society, many scientists claim that humans need to sustain the belief in their ability to freely decide (Gholipour, 2019). 

Luckily, humans possess the feature of “cognitive dissonance” (Iek, 2019), so that, even if future research would uncover direct evidence against the free will, we would allow ourselves to ignore it.


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