Lecture 13: The Enigma of Free Will PDF

Lecture 13 The Enigma of Free Will A sense of being able to choose different courses of action is a clear characteristic of our subjective experience. But is it a sense of a freedom that is itself real? Or is our sense of free will merely an illusion? This lecture will focus on both the classic...

Lecture 13 The Enigma of Free Will A sense of being able to choose different courses of action is a clear characteristic of our subjective experience. But is it a sense of a freedom that is itself real? Or is our sense of free will merely an illusion? This lecture will focus on both the classic philosophical problem of free will and the way in which questions of free will arise in contemporary scientific research. There is much that the philosophical and scientific approaches have in common. But there are also important ways in which they differ. The Problem ●● The universe is governed by cause and effect. What happens at noon Monday is determined by everything that happened before noon Monday. If what happens at any step is entirely a result of what happens at the step before, everything at every step is determined by what happened before. All history is determined. That’s the determinism side of the so-called problem of free will and determinism. ●● The other side of the problem is the free will part. Our lives—all lives— involve a series of choices. If you trace back the course of your life, you can map it out like a branching tree diagram of choices faced and decisions made, followed by further choices faced and decisions made. ●● The problem is that the two pictures we’ve painted don’t fit together. We think of our lives using the second picture: free will. But the way we think of the universe seems to have the first picture built in: determinism. 130 M ind - B ody P hilosophy ●● One option when faced with this dilemma is to buy the deterministic picture and to kiss free will goodbye. The universe operates by physical laws written in terms of natural forces and fundamental particles. Free human choice isn’t part of the picture. It is at best an illusion. ●● Another option is to clutch onto free will, denying the deterministic picture in order to maintain the picture we’ve painted of free decisions, free choices, genuine responsibility, and sometimes grounded regret. Scientific Confirmation? ●● One of the best-confirmed scientific theories of all time is quantum mechanics, the physics of the very small. We have mathematical formulations of the theory that give us, solidly and reliably, the right quantitative results— often strange and unexpected. ●● Things become very confusing when we ask not merely how the formulas operate and what they predict but what they are telling us about how the universe works at a fundamental level. For instance, quantum mechanics doesn’t merely tell us that we don’t know why a particular atom decays at a particular time. It tells us there is nothing to know. There is no reason why a particular atom decays at a particular time. ●● The implication of this scientific picture is that the universe isn’t deterministic. Not every event is determined by earlier events: The decay of a particular uranium nucleus isn’t so determined. While the 19th-century physics of Newton outlined a deterministic universe, 20 th-century quantum mechanics tells us that picture is wrong. ●● So perhaps that settles it: Our best science tells us that the universe isn’t deterministic after all. There is space for free choice, responsible decisions, and free will after all. ●● Some thinkers have made precisely that argument, claiming that quantum randomness allows for free will. But that is a step too far and too fast: If some events happen for no reason, how precisely does that give you free will? L ecture 13 — T he E nigma of F ree W ill 131 Ancient Debates ●● Much of the debate over free will, determinism, and randomness played out long before quantum mechanics arose. Stoicism and Epicureanism were two schools of Greek philosophy that continued into the Hellenistic or Roman period. Although Stoics and Epicureans were both materialists, the two schools had a very different take on free will. ●● The Epicureans took something like the quantum line. The Latin poet and philosopher Lucretius gives one of the most complete outlines of Epicureanism we have. Everything is material, including the mind, but the atoms of which things are made occasionally “swerve.” Lucretius tempers his determinism with randomness in order to carve space for free will. ●● The Stoics, on the other hand, were strict determinists. In full acceptance of an unbreakable chain of cause and effect, everyone’s fate is sealed. The best one could do, the Stoics said, was to bear it stoically. That has problems too: If everything is determined, it will be determined whether you suffer your fate or freely accept it. Even there you wouldn’t be free. Roman philosopher Seneca 132 M ind - B ody P hilosophy Compatibilism ●● An alternative approach is to reject the dilemma itself: Maybe, once we really understand the philosophical issues involved, we will see that free will and determinism are compatible. Not surprisingly, this is known as a compatibilist approach. ●● The basic idea is well captured in a quote from the American philosopher John Dewey: “What men have esteemed and fought for in the name of liberty is varied and complex—but certainly it has never been a metaphysical freedom of will.” ●● Dewey is emphasizing that metaphysical freedom—freedom from chains of causality—is not the freedom that we care about. What we care about is freedom from tyranny, from oppression, from chains of iron. It may also be freedom from addiction and compulsion. To want those kinds of freedom isn’t to want to be metaphysically independent of cause and effect. Freedom in the sense worth caring about is freedom from coercion, not freedom from causality. Grey Walter’s Experiments ●● Now let’s shift to questions of free will in a scientific context. We will examine two very suggestive sets of experiments. ●● The first set of experiments, conducted by the neurologist Grey Walter, date to the 1960s. Walter implanted electrodes in the motor cortex of brain surgery patients. Those enabled him to record a pattern of activity called readiness potential: a burst of electrical activity in the motor cortex that precedes actions like moving your arm, or hand, or finger. ●● Grey Walter’s hypothesis was that those bursts of activity in the brain didn’t merely precede voluntary action. They were the initiation of the causal chain of voluntary action, from brain to hand. In order to test the hypothesis, electrodes were implanted in the area of the brain associated with finger movement. L ecture 13 — T he E nigma of F ree W ill 133 He then asked his patients to control the movement of an old-fashioned carousel slide projector: When a patient wanted to see the next slide, they’d press the button. ●● Grey Walter rigged the slide projector so that what actually triggered the slide change wasn’t the press of the patient’s finger, but the readiness potential in the motor cortex. There was a direct brain-to-slide projector connection instead of the normal finger-to-slide projector connection. ●● The decision to change the slide was still up to the patient. The patient would then reach to press the button in order to change the slide. ●● Curiously, that wasn’t how Grey Walter’s patients experienced it at all. Instead, they reported that the slide projector clicked to the next slide just before they decided to move it. ●● The results seem to mean that we had the timing of events wrong. This order is incorrect: First, we have that moment of conscious decision; that activates the readiness potential; and that produces the movement. Instead, the order seems to be: First, the readiness potential starts the chain of events; then we have that moment of conscious decision; and then the finger moves. Benjamin Libet’s Experiments ●● A later set of experiments by Benjamin Libet seem to show much the same effect. Libet, like Grey Walter, wanted to know how spontaneous voluntary action worked and to know about the timing of events in the brain and the moment of conscious decision. ●● Libet’s method was to ask subjects about when they decided to move not at the time of the decision, but later. He asked his subjects to move their right hand any time they felt like it, but to watch a spot of light revolving in a circle as they did so, something like a rotating hand on a clock. Subjects were to remember where the spot of light was when they decided to move their hands. The light served as a timekeeping measure: Each person could report where the light was when they decided. 134 M ind - B ody P hilosophy ●● The experiment also recorded the timing of the readiness potential in their brains and the moment at which their hands actually move. The findings: The subjective intention or decision to move comes about 200 milliseconds—a fifth of a second—before the movement itself. ●● But the readiness potential comes about 535 milliseconds before the movement itself. That’s over half a second before. That means the readiness potential that makes your finger move comes before you are aware of a decision or intention to move. ●● The simplest interpretation—the one Libet offers—is that your experienced decision or intention can’t be what actually makes your finger move. Your brain is well on its way to making your finger move almost 350 milliseconds before you think you are deciding to make it move. Your subjective experience of deciding to move your finger comes more than a third of a second after the process is already in play. Interpreting ●● Do those experiments show that we don’t have free will? When we ask that, we’re not asking merely what happened in the experiments. We’re asking how to interpret what they really mean. ●● Libet himself seems uncomfortable with the conclusion that free will is an illusion. Although the readiness potential starts the chain to movement, Libet claims that some of his data show that it is possible for that chain to be consciously interrupted before the movement actually happens. Libet speaks of this as a veto function. ●● There are other examples in which consciousness seems a late arriver. Sports excellence often relies on split-second timing. At times, those split seconds are too fast for consciousness to play the kind of role we might expect. ●● For a time, the reigning champion in the 100-meter was Linford Christie. In the 1996 Olympics, Christie was disqualified for twice jumping the gun. Video replay clearly shows that the starter pistol was fired before Christie L ecture 13 — T he E nigma of F ree W ill 135 started to move. Nevertheless, the officials stood by their decision. A similar outcome befell John Drummond in the 100-meter quarterfinal of the 2003 World Championships. ●● How is that fair? Both Christie and Drummond moved only after the gun had fired. The answer is that since the 1970s, false starts have been determined with great precision, both electronically and with careful attention to reaction times. Typical reaction time for top-level competitors is something like 125 to 250 milliseconds. If a runner reacts significantly faster than that, they can’t have heard or seen the signal and then started. Drummond, for example, moved in less than 100 milliseconds after the signal. He jumped the gun, said the officials. The Takeaway ●● The Walter and Libet experiments do seem to show that a particular picture that we have of free will is often wrong. It’s not true that a moment of decision precedes voluntary action in all cases. ●● That doesn’t mean, however, that the picture is always wrong: A person can decide to marry a spouse long before they pop the question. It is in terms of milliseconds and instantaneous spontaneous action that the picture fails, not in the minutes, hours, days and years of our deliberate action. 136 M ind - B ody P hilosophy ●● Maybe the standard picture—deliberation first, decision initiating action— is right for the kind of free will we really care about: freedom in major choices, important decisions, even decisions about whether to do the shopping now or later. ●● If our picture of free will is one in which every movement in every context has to be initiated by a moment of conscious decision in order to be free, we’ll have to conclude that in that sense many of the simple movements we make are not free. But that may not be the kind of freedom we really care about, either. Suggested Reading Dennett and Kinsbourne, “Time and the Observer.” James, “The Dilemma of Determinism.” Libet,  “Unconscious Cerebral Initiative and the Role of Conscious Will in Voluntary Action.” Questions to Consider 1 Do you think you have free will? In your answer, specify precisely what you mean by free will. 2 If you said yes in answer to question 1, what would convince you that you didn’t in fact have free will? L ecture 13 — T he E nigma of F ree W ill 137