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Are our choices ever truly free? The philosophical problem of free will is a deep and abiding one that has been around since at least the time of the Ancients. And as our knowledge of the human brain has grown over the last century, the problem of free will has gotten even more complicated.
Some neuroscientists go so far as to claim that there is simply no such thing as free will. The feeling we sometimes have of freely choosing is just an illusion, a trick of the mind, they say. We might think we are making free choices, but, in fact, the choice has already been made before we become aware of it.
But what, you might ask, would a neuroscientist know about the philosophical problem of free will?
Unfortunately, the answer, more often than not, is “not much.” Many seem happy to make these sweeping claims about free will without so much as a thought about what it would take to prove or disprove the claim that we sometimes make free choices, or what it even means to make a free choice, and in what kinds of contexts the question arises.
That’s not to say that neuroscience is completely irrelevant to the problem of free will. Even Descartes, who famously claimed that the mind is an immaterial or spiritual substance, completely separate from the material world, recognized the importance of the brain for our mental lives. He simply thought it was the locus of interaction between these two radically different substances -- mind and body. But today we know that there’s a lot more to say about the brain’s role in our mental lives. So, it makes sense that we should look to neuroscience for answers about how we make choices and decisions. Surely neuroscience has something to tell us about the nature of free will!
But could neuroscience ever prove that our decisions are made before we’re even aware of them? In our subjective experience of ourselves, we appear capable of making conscious decisions and acting on them. For example, you could decide to stop reading this right now, or you could decide to continue. It’s up to you. Maybe there are outside pressures and influences that play a role in your decision, like you’ll be late for an appointment if you keep reading, but ultimately the choice is yours to make. If you keep reading and you end up being late for your appointment, you have to accept responsibility for that because that’s what you decided to do. Your interest in the question of free will might in some way compel you to keep reading, but you could decide that being on time is more important. The decision up to you. Right?
If that's the case, then exactly how could neuroscience ever prove that your subjective experience of freely choosing is just an illusion, that your decisions are made before you even know it?
One of the most famous experiments cited in defense of this radical claim comes from the work of neuroscientist Benjamin Libet in the eighties. He measured subjects’ brain activity while they repeatedly pressed a button at random intervals. The subjects were asked to make note on a special clock when they first became aware of their intention to press the button. And guess what? They discovered that a couple of hundred milliseconds before subjects became aware of their intention to press the button, their brains were already preparing to move the finger. So, Libet concluded, the brain had already "decided" to move before the subject even knew of her own intention.
Libet's ultimate conclusion from these experiments is that consciousness plays no role in what we decide to do, except perhaps as a veto to the unconscious “decisions” our brain makes. Therefore, free will is an illusion.
If you’re thinking that this conclusion is a tad too quick, you’d be absolutely right. If you had some stronger language to describe the “reasoning” involved here, we could probably compare notes some time. But before we do that, let’s think about what reasonable conclusions we might possibly infer from Libet’s data.
I think the best we can conclude is that sometimes our subjective experience is not a reliable indicator of what’s really happening. This is true for pretty much any perception we have. We make mistakes sometimes, or we’re susceptible to various tricks and illusions. I’m not sure we really needed Libet’s experiments to prove that, but let’s set that aside for now.
In Libet’s experiment, the subjects presumably thought they were freely making conscious decisions about when to push the button, but if Libet’s interpretation of the data is right, then their brains had already decided to press the button before they were even aware a decision had been made. What seemed to the subjects like a conscious decision was really more like a notification of the unconscious decision their brains had made. Hence, the subjective experience of consciously deciding and then acting based on that decision is not always reliable. Sometimes, we think we’re deciding something that has already been decided.
Any student who has taken Logic 101 will tell you that you can't validly infer an "always" from a "sometimes," though you'd hope their critical thinking skills were not so underdeveloped that they needed to be explicitly taught this. Given that, it's somewhat of a surprise that a respectable scientist, like Libet, would commit such a blatantly horrible fallacy.
At most, then, Libet's experiments show that sometimes we don't freely decide when we think we do. But I don’t think even that conclusion is plausible.
For a start, it depends on Libet’s interpretation of the data being correct, namely, that what is measured in the brain a few hundred milliseconds before the subject reports a conscious decision is correctly described as an “unconscious decision.” As Alfred Mele and other philosophers have pointed out, there are clear distinctions to be made between urges, intentions, plans, and decisions, and Libet seems to just assume that what he measured should be interpreted as a “decision” rather than the more probable “urge” (if our conscious minds are able to “veto” it before we act). There is no reason to think Libet’s particular interpretation is correct, and the fact that we might have an unconscious urge or a vague plan to come to a decision before we actually make the decision should not surprise anyone.
Moreover, what does it even mean to say that “your brain has already decided”? Brains don’t make decisions, people do! That may seem like a glib response, but I mean it quite seriously.
In our folk psychological theories, we attribute all kinds of mental states to one another, like beliefs and desires, fears, plans, intentions, and so on. Using these concepts allows us to make sense of ourselves and one another. We can explain behavior by appeal to these mental states.
These are states that we attribute to persons, not specific organs in their body, even when those organs are deeply involved in the person being in that particular state. For example, we might say that Jenny is feeling hungry, but it would be odd to say that her stomach is hungry. The rumbling of her stomach might indicate that she is hungry, but it’s Jenny, the person, who feels the hunger, not her stomach.
Similarly, we might attribute fear to Jenny, but not to her amygdala (the part of the limbic system involved in fearful responses). I doubt if it ever makes sense to say that her amygdala feels anything. Nevertheless, we can recognize the central role it plays in processing and responding to fearful stimuli. But again, it is Jenny, the person, who feels the fear, not her amygdala.
Applying the lesson here to the Libet case, we can say that a subject in the experiment made a decision to move her finger and that a particular part of the motor cortex where activity was recorded was involved in that decision-making process. But does it make any sense to say that the motor cortex itself made the decision? I don’t think it does. Yet Libet just assumes that what we can attribute to a person can just as sensibly be attributed to specific parts of her body.
Even when particular parts of the body are deeply involved in generating the person’s feelings, like the stomach in the feeling of hunger, or the amygdala in the feeling of fear, it still doesn’t make sense to apply these personal concepts to parts of the body. Libet is not entitled to simply assume that the activity he measured in the motor cortex is a “decision.” He would have to do a lot of work to justify this interpretation of the data, whereas instead, he is, apparently, completely oblivious to the problem.
At best, Libet’s experiments show that the brain is involved in decision-making. But who these days would have doubted that?
Clearly, I’m not impressed with Libet. But there have been more recent experiments, like one by Chun Soon, in which so-called “free choices” were accurately predicted up to ten seconds before subjects were even aware of their own choices. Recall, the activity that Libet measured in the brain happened less than half a second before the subject consciously decided, whereas in Soon’s experiments, they were able to predict several seconds beforehand what the subject was going to choose. That may seem to present a stronger threat to the notion of free will than Libet’s experiments.
I don’t want to get into the details of Soon’s experiments, but I do want to end this post with some general comments about what neuroscientists are doing, and what this says or does not say about whether we have free will.
That our mental events have antecedent physical causes is not news for any philosopher who works on the problem of free will. And that’s pretty much all these experiments show. The decisions we make don’t just happen randomly in some vacuum -- they are part of the natural world of causes and effects.
Most philosophers who work on the problem of free will these days are what we call “compatibilists” as opposed to “libertarians” (not to be confused with political libertarians). They think that freely choosing is compatible with a causally determined universe. They understand that our decision-making is enmeshed in a network of inner and outer causes. So, showing that something played a role in causing a decision doesn’t do anything to undermine the possibility of free will. It’s neither here nor there.
Granted, if you start out with a libertarian notion of freedom -- one that asserts our free will, while denying that the universe is causally determined -- then, sure, neuroscience threatens to upturn your applecart. But who takes libertarian freedom seriously anymore? Neuroscience, apparently, hasn’t gotten the message.