I think, Therefore I am

Cecelia Ky-Lan Do
May 5
11 min read

by Nick Thomas

art by Vivian Yang

Which came first - the chicken or the egg?

The question presents one of the most classic examples of cyclic reasoning:

“I mean, it could be the egg, since a chicken must hatch from an egg. But then again, doesn’t an egg require a chicken to lay it in the first place? Maybe it’s the chicken, then? But that chicken would need to come from an egg itself… which was laid by a chicken before it.” And soon enough, our argument becomes an endless loop of chickens and eggs, becoming chickens and eggs all the way down.

A similarly difficult, yet more serious, set of questions regarding the existence of free will has existed in philosophy for centuries: Do we really have free will? How do we define free will? What does it mean for us to truly act on our own accord? Naturally, as a field that surrounds the mind and behavior, neuroscientific researchers have begun to tackle this question empirically. Since then, a majority of neuroscientific research surrounding free will revolves around a chicken-and-egg-like question: when we make a decision, is our conscious mind in charge of our brain, or are the biological impulses of our brain in charge of us? In other words, which comes first—our conscious decisions or our brain’s biological impulses?

Neurons All the Way Down

Imagine that you are working at a desk, when you impulsively decide to pick up your phone (as one naturally does when working). What caused this movement? Was it a conscious process or just a result of our underlying neurobiology?

To answer this question from a neuroscientific perspective, we can start by examining our first exercise of volition and build backward. Mechanistically, the muscles in your arms and hands extend and contract because they are stimulated by motor neurons experiencing an action potential, when a neuron reaches an excited state that results in neuronal firing [1]. Those motor neurons were stimulated by action potentials from higher-level cortical areas of the brain that planned out the movement. These cortical neurons experienced their own action potentials because of the neurons before them, and so on. Soon enough, our argument becomes neurons all the way down [1].

Philosophically, it has been argued that in order to be granted free will, one must be the author of one’s own choices, without the interference of people or mechanisms outside of their [2]. A great deal of research in neuroscience focuses on tracing the neural origins of volition, such as this study that proved that the decision to move a right index finger could be overwhelmingly traced back to only 256 neurons [3]. A greater understanding of the neural roots of free will in other, potentially non-mechanical, tasks could provide us with a possible solution to our question over it [3]. However, such experiments are virtually impossible to replicate in a lab, because the brain produces constant passive background activity that overshadows meaningful signals [4]. What makes this perspective even more confusing are the external factors that can dictate the activation of these neurons. Perhaps, for example, you have built up a reliance on your phone use and are looking for a dopamine spike (a neural signal related to rewarding behavior) in the middle of your work. In this case, both your neurochemistry and past habits played a role in the action. Your genes, immediate surroundings, lived experiences, and ecology also generally influence your decision-making process, and may have subconsciously played a role in this movement. For these reasons, prominent neurobiologist Dr. Robert Sapolsky concluded in his 2023 work Determined: A Life of Science Without Free Will that we are “nothing more or less than the cumulative biological and environmental luck, over which we had no control, that has brought us to any moment” [5]. In essence, Sapolsky believes that free will does not exist, arguing that given the various biological factors, it is virtually impossible to find a neuron or action that is completely unimpacted by factors outside of our control, such as our genes or upbringing. “In order to prove there’s free will, you have to show that some behavior just happened out of thin air, unaffected by all these biological precursors. It may be possible to sidestep that with some subtle philosophical arguments, but you can’t with anything known to science,” Sapolsky argues [5].

Timing Free Will

So, how is free will productively researched? Surprisingly, neuroscience has its own subfield for these very such questions—neurophilosophy. Neurophilosophy is an interdisciplinary field integrating neuroscience, psychology, and philosophy to inform philosophical topics and establish a mind-body type relationship [6]. One of the most prominent researchers in this field, Benjamin Libet, attempted to find an answer to the free will debate. His 1983 experiment has since become key to the field and even survived scrutiny for most of its findings in a modern recreation of the original experiment by Tomas Dominik and colleagues [7, 8]. In the original experiment, Libet connected participants to an electroencephalogram (EEG), a device that measures the electrical activity in the brain due to the activation of neurons, and presented a button and a large clock to participants. Participants were then prompted to imagine a stimulus of their choosing—say, a pink elephant. Libet then monitored the EEG to observe any specific spikes in neuronal activity. Participants were then instructed not to think of a pink elephant right at that moment, but to think about it in the near future.

When they chose to imagine the elephant, they pushed the button in front of them and recorded the time on the clock. On average, participants reported that they decided to think about the stimulus about 200 milliseconds before their finger started moving to press the button, expressing a form of conscious decision-making before an action is initiated. Libet also discovered a distinct EEG pattern that spiked 300 milliseconds before people decided to push the button, which he termed a “readiness potential” (RP). This readiness potential is associated with the supplementary motor area (SMA) of the brain: an area that functions in initiating voluntary, complex movements. According to Libet, this impulse in the SMA would occur before participants were even conscious of making a choice—their brains had already chosen to imagine the stimulus about 300 milliseconds before they were even aware of it. Libet’s experiments were seen as strong evidence against free will in the world of neuroscience [7, 8].

Libet’s study resulted in an explosion of corresponding free will studies. Yet another cornerstone study arose in 2008, when neuroscientist Dr. John Dylan-Haynes and colleagues used functional magnetic resonance imaging (fMRI) to more accurately track the movement of blood as a measure of the neural activation in different decision-making areas of the brain [9]. Similar to Libet’s studies, Dr. Dylan-Haynes placed participants in an fMRI machine and presented them with a series of flashing letters. Participants were told to press a button at any point and to remember the letter that appeared when they made the conscious decision to press the button. Dr. Dylan-Haynes’s discovery solidified Libet’s findings: the decision-making areas of the brain spiked in activity, as indicated by increased blood flow to the frontopolar prefrontal cortex (involved in high-level decision planning), anterior cingulate cortex (known for its role in conflict monitoring), and parietal cortex (more generally used in action planning). All of which increased in activity around a full seven to ten seconds before participants were even aware they had made a decision [9].

So is our concept of free choice just an illusion? Does our brain make a decision and later fill in our conscious minds? While Libet’s (and Haynes’) conclusions have garnered supporters in the field of neurophilosophy, they have also sparked outrage. Some critics argue that Libet’s experiments use a very narrow definition of “free will”: to Libet, if an individual’s self-reported time of their conscious decision to imagine a stimulus occurred before this readiness potential, there existed proof of free will. Manuel Vargas, a professor of philosophy at the University of California, San Diego, critiqued Libet’s research, arguing that Libet-style decisions only encompass a small part of daily decision-making, which bear little resemblance to whether free will is impacted by our beliefs and values [10]. To Vargas, Libet’s research focuses more on simple decision-making processes (questions like “What will I order at this restaurant?”), and less on long-term goals (“Where do I want to live in the future?”).

Another criticism of Libet’s research is his extensive focus on the motor system. As a physical manifestation of the decision-making process [11], Libet utilizes the motor system (i.e., pressing a button when you think of something) as an indicator of a conscious thought being formed. As many argue, this represents a limited understanding of voluntary action, completely excluding any internal actions that require no muscular activation (e.g. shifting your attention from one object to another). This has ultimately resulted in tens of replication studies of Libet’s original methods, usually with some factors changed. In a 2019 review of these replicatory studies, researchers discovered that the presence of the RP does not suggest that our brain has finished making a decision before our consciousness is informed, but rather that the brain is still in the process of making a decision. The decision is then fully realized by the participant when a certain hypothetical “decision-making threshold” is passed (i.e., the brain has thought long enough to formally make a decision). This is the moment, the researchers hypothesize, when we are informed of the decision; we make the realization at roughly the same time that our biological impulses in our brain do [11].

Moreover, the limited operational definitions of free will are once again stressed. Free will, as many philosophers and neuroscientists argue, is likely a long, fragmented process that closely reflects the larger aforementioned decisions we make (i.e. “Where should I live in the future? What are my core values?”). In another 2015 review of Libet’s experiments, researchers argue that free will might not be a specific, singular event, but rather a “durationally extended process” [12]. It is further argued that free will is likely constructed from various subprocesses, which could leave space for our own conscious intentions and their role in decision formation [12].

“Free Won’t”

Interestingly, Libet himself did not fully endorse his rather strict model of free will. Libet, instead of believing that we have free will, posited that we have “free won’t,” the ability to consciously override an initiated action. This “vetoing” of an action, as Libet theorized, gives us a sense of free will in the opposite direction [13]. Taking us back to our phone example, if some impulse told us to pick up our phone while working, our conscious awareness could suppress it, in an act of “free won’t”: “I shouldn’t check my phone right now.”

In a 2015 experiment, Dr. Furstenberg of Hebrew University and colleagues tested Libet’s hypothesis using a variety of button “primers” [14]. In these tasks, participants were connected to an EEG and told to choose between a left and a right button. Before making this decision, participants were presented with a primer on a screen in front of them, in the form of an arrow that would point either left or right for a few milliseconds. This primer would influence participants to choose a certain direction, essentially making the decision for them. In the cases that participants expressed their “free won’t” and chose an arrow opposite to the primer, researchers found a shorter RP of around 100 milliseconds. This response arose from a similar neural pathway as in Libet and Dylan-Hayne’s experiments, beginning in the prefrontal cortex, moving into the SMA, and finally moving outward to motor areas. The difference between the average RP found in Libet’s experiments and the shorter RP observed when Furstenberg’s participants exercised their “free won’t” suggested that there was a certain type of timed difference between the activation of a choice and the suppression of a choice. This difference supports the idea that the presence of RPs indicates that the brain is simply in the process of making a choice, rather than having already finalized a decision. Because the brain can veto a choice in a shorter amount of time than Libet believed was necessary to make one, we have reason to believe that the brain is still making the choice within Libet’s RP. In essence, the decision hasn’t been formalized yet, and our conscious mind does not lag as far behind our brain as we previously thought it did [14].

The Choice of Free Will

Imagine (for the last time) yet another button, accompanied by a light. In his short story “What’s Expected of Us,” neuroscientist Dr. Ted Chiang likens the way neuroscientists think about free will to this imagined machine [15]. Whenever you choose to press the button on this machine, the light flashes just a second before you do so. No matter what you do, one second before you press the button, the light will go off. You may try to strategize, walk away from the machine for some time and come back, or even sneak up on the button, but the light will always come on just a second before you press it. Basically, the action you are about to commit is already a determined past. In Dr. Chiang’s story, everyone who interacts with the machine eventually gives up, and some people, “realizing their choices don’t matter, refuse to make any choices at all” [15].

When we consider the results discussed in the keystone studies surrounding the neuroscience of free will, it is especially easy to take a doomist perspective. If, for example, our brain does in fact make every decision before we are consciously aware of them, is there a point to these conscious decisions? In the face of this troubling question, it is important to remember that neuroscience only provides a very narrow definition of free will. Perhaps we should change our perspectives and the kinds of questions we ask about free will. Instead of asking “Do we have free will?” we can instead ask “What kinds of neural processes give rise to my sense/experience of agency?” Additionally, the results do not completely invalidate free will just on the basis of someone’s choice to push a button. Perhaps, free will is not a single event, but is interwoven between our consciousness and neural activity, distributed across numerous neural networks, and constructed over a period of time. Free will may not only be strictly defined by our neural mechanisms, but also by how we apply ourselves to the world.

In closing his short story, Dr. Chiang is literal with his audience: “My message to you is this: pretend that you have free will. It’s essential that you behave as if your decisions matter, even though you know that they don’t” [15]. Even if this perspective is eventually revealed to be true, Dr. Chiang argues in favor of free will: we must live as though our decisions matter, because within our lived experiences, they do.

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I think, Therefore I am

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