For centuries, free will has been a hotly debated topic in philosophy and science. Some believe free will is an illusion, while others believe it is fundamental to human nature. The most intuitive definition of free will is the ability to make autonomous and conscious decisions free from constraints. However, whether free will exists or not remains inconclusive.
In recent years, technological advances have made it possible for neuroscientists to peer inside the human brain to understand the mechanisms that permit conscious causal control of our actions. Could empirical science settle this perennial free will debate by presenting a case for determinism of higher mental processes? To better understand this, we must first understand the philosophical and scientific perspectives of free will. Then, we can evaluate the empirical research from neuroscience and experimental cognitive and social psychology to better our understanding of this controversial topic.
The concept of free will is complex. There are three main philosophical conceptions of free will. Hard determinists believe that human choices and actions are causally determined by forces outside our control, such as biology and past experiences. In contrast, libertarian free will believers think that agents can think and act voluntarily without external physical obstacles or conditions. They support the source-hood hypothesis that agents cause their free actions, which result from previous free undetermined actions. Compatibilist free will believers assert that agents maintain individual freedom in a deterministic universe. Free actions are caused by agents' internal characteristics, making them responsible for their actions, and the veracity of causal determinism does not subvert our ability to do otherwise.
Neuroscientists' approaches to free will are more mechanistic. They look for the precise relationship between intention (cause) and outcome (effect) underlying voluntary actions or conscious control. They converge on a version of free will that is operationalised as the conscious control, specifically the intention or desire, to generate bodily movements voluntarily. These mental processes cause the physical actions that constitute an agent's behaviour. This angle of free will has forced us to think about what role volition and a sense of agency (SoA) might play in free will. Volition is the process of making a conscious decision to act, while SoA is the subjective feeling of being the cause of one's actions.
The debate over free will is complex, and there is no easy answer. However, by understanding the philosophical and scientific perspectives on free will, we can better appreciate the different arguments and evidence that have been put forward. This can help us form informed opinions on this critical question.
One of the most common challenges to free will is the epiphenomenal challenge. It argues that conscious decisions and intentions are simply epiphenomena, or by-products, of brain processes that control our actions. In other words, our conscious decisions do not cause our actions; they are merely the result of brain processes already in motion. Some evidence supports the epiphenomenal challenge in neuroscience and psychology, suggesting that free will is an illusion.
The Readiness Potential
The discovery of readiness potential (RP) by neuroscientists Deecke and Kornhuber in 1969 further supports the notion that free will is epiphenomenal. The RP is a brain signal linked to planning, preparing, and initiating voluntary acts. Its discoverers believed that the RP causes the action, and this assumption has been used to argue that free will is an illusion. In the 1980s, Benjamin Libet used the RP to make a neurological case against free will. He asked participants to press a button "at will" while watching a clockface and to remember the moment they felt the urge to move while measuring their brain activity with EEG. The results showed that the RP, or the volitional processes, began 550 milliseconds before the participants pressed the button. However, they reported their decision to take action only 150 milliseconds beforehand. Libet concluded that the RP, or unconscious neural activity, precedes the conscious subjective feeling of volition. This suggests that our actions are not entirely under our control and that free will is an illusion.
Studies in experimental psychology further the epiphenomenal argument. One study by Wegner and Wheatley (1999) investigated the illusion of choice - when people experience a sense of agency (SoA) even when they have no control over an outcome. In this study, participants were presented with several stimuli and asked to indicate which stimulus they believed would appear next. However, the stimuli were presented randomly, and the participants' responses did not influence the outcome. Despite this, the participants still reported feeling a sense of agency, as if they consciously chose which stimulus to appear next.
This study highlights that our understanding of agency is only sometimes accurate and may be based on our brains' inferential mechanisms, which try to make sense of the sensory information we receive. Our inferential mechanism uses sensory information to interpret the causal origins of the actions and their experiences, known as retrospective inference. Hence, the SoA does not precede the action; instead, the SoA is a consequence.
The illusion of choice provides compelling evidence that consciousness is an epiphenomenon. It suggests that our sense of agency does not directly reflect our actual causal influence on the world. Instead, it is a product of our brains' inferential mechanisms, which try to make sense of the sensory information we receive. This finding has important implications for our understanding of consciousness. It suggests that consciousness is not as central to our cognitive processes as we once thought. Instead, it is more of a side effect of our brains' attempts to make sense of the world.
Kahneman's dual processing theory suggests that our cognitive architecture comprises two mental processes: System 1 and System 2. System 1 is fast, automatic, and unconscious, while System 2 is slow, reflective, and conscious. Kahneman argues that we use System 1 more than System 2 and that this can limit our free will. For example, System 1 can overrule our conscious choices, making us act in ways we do not intend. The findings from Kahneman's dual processing theory suggest that free will is more limited than we would like to believe. Others believe that free will is real but limited. They argue that we have some degree of control over our actions, but our unconscious biases and heuristics constrain this control. The extent to which free will exists is a complex question that philosophers and scientists are still debating. However, Kahneman's dual processing theory provides a valuable framework for understanding the nature of free will and its limitations.
The Sense of Agency: A Marker of Free Will
The sense of agency (SoA) is the experience of being the source of one's actions. It is the feeling that we are in control of our behaviour and that our actions are not simply the result of external forces or automatic processes. A growing body of research suggests that belief in free will can influence the SoA.
One way to measure the SoA is to use intentional binding. In this task, participants are asked to make a voluntary movement, such as pressing a button. The time at which the participant presses the button is recorded, and then the participant is asked to estimate the time at which they felt the intention to press the button. Studies have shown that people who believe in free will tend to experience a stronger intentional binding effect. This means they tend to underestimate the time between the intention to act and the actual act, suggesting that those who believe in free will are likelier to feel a sense of unity between their intention and action.
Another measurement of SoA is a technique called the comparator model, where SoA is based on comparing our predicted and actual states. When we make a voluntary movement, we have a prediction of what the outcome of that movement will be. We will likely experience a strong SoA if the outcome matches our prediction. Studies have shown that people who believe in free will tend to experience a stronger SoA when the result of their actions is predictable. This suggests that people who believe in free will are likelier to feel a sense of control over their actions when they know their outcome.
Researchers believe that by investigating SoA, we can determine when an action is voluntary, giving rise to the view that free will requires an SoA. However, these findings have remained purely correlational, and they have yet to explain a causal link between free will beliefs and SoA or measures the free will defended by philosophers. The research into SoA remains significant as it will help us determine whether the belief in free will is justified.
The belief in free will is a fundamental part of our identity. This conception of ourselves has broad implications in the real world for social functioning, from criminal responsibility and punishments to health and well-being and public policies derived from these conceptions of self. The belief in free will also has implications for the law and our moral judgments. In many legal systems, people are only held responsible for their actions if they were done voluntarily. This means that if someone is not believed to have free will, they may not be held accountable for their actions.
The research on the SoA and the belief in free will is still in its early stages. However, the findings suggest a strong link between these two constructs, and the research suggests that these constructs are essential for our well-being. By understanding more about these constructs, we can better understand ourselves and our place in the world. While we know that free will is based on a presupposed philosophical worldview, empirical science research on free will has not been compatible with this position, presenting an opportunity for philosophers and scientists to elucidate the concepts essential to free will and its impact on SoA, as the implications for this in the social and legal discourse is significant.