One of the most fervent of late 19th century materialists, T.H. Huxley, described human beings as “conscious automata” with no free will. As he explained in 1874, “Volitions do not enter into the chain of causation…. The feeling that we call volition is not the cause of a voluntary act, but the symbol of that state of the brain which is the immediate cause.“
This was a very early formulation of an idea that has become commonplace amongst modern scientists and philosophers who hold similar materialist views: that free will is an illusion. According to Daniel Wegner, for instance, “The experience of willing an act arises from interpreting one’s thought as the cause of the act.” In other words, our sense of making choices or decisions is just an awareness of what the brain has already decided for us. When we become aware of the brain’s actions, we think about them and falsely conclude that our intentions have caused them. You could compare it to a king who believes he is making all his own decisions, but is constantly being manipulated by his advisors and officials, who whisper in his ear and plant ideas in his head.
Many people believe that evidence for a lack of free will was found when, in the 1980s, scientist Benjamin Libet conducted experiments that seemed to show that the brain “registers” the decision to make movements before a person consciously decides to move. In Libet’s experiments, participants were asked to perform a simple task such as pressing a button or flexing their wrist. Sitting in front of a timer, they were asked to note the moment at which they were consciously aware of the decision to move, while EEG electrodes attached to their head monitored their brain activity.
Libet showed consistently that there was unconscious brain activity associated with the action—a change in EEG signals that Libet called “readiness potential”—for an average of half a second before the participants were aware of the decision to move. This experiment appears to offer evidence of Wegner’s view that decisions are first made by the brain, and there is a delay before we become conscious of them—at which point we attribute our own conscious intention to the act.
However, if we look more closely, Libet’s experiment is full of problematic issues. For example, it relies on the participants’ own recording of when they feel the intention to move. One issue here is that there may be a delay between the impulse to act and their recording of it—after all, this means shifting their attention from their own intention to the clock. In addition, it is debatable whether people are able to accurately record the moment of their decision to move. Our subjective awareness of decisions is very unreliable. If you try the experiment yourself—and you can do it right now, just by holding out your own arm, and deciding at some point to flex your wrist—you’ll become aware that it’s difficult to pinpoint the moment at which you make the decision.
An even more serious issue with the experiment is that it is by no means clear that the electrical activity of the “readiness potential” is related to the decision to move, and to the actual movement. Some researchers have suggested that the readiness potential could just relate to the act of paying attention to the wrist or a button, rather the decision to move. Others have suggested that it only reflects the expectation of some kind of movement, rather being related to a specific moment. In a modified version of Libet’s experiment (in which participants were asked to press one of two buttons in response to images on a computer screen), participants showed “readiness potential” even before the images came up on the screen, suggesting that it was not related to deciding which button to press.