From Robert Lawrence Kuhn, host and creator of Closer to Truth:

If it seems perfectly obvious that your will is free, that “you” are able to decide and choose as “you” quite please, then it seems perfectly clear that you don’t get it. Free will is a huge problem.
I’d never thought “free will” to be a problem. If I want to walk, I walk; sit, I sit.
Here’s the problem. Since every physical event has a prior and sufficient cause, then every current movement of atoms is caused by some prior movement of atoms, including all those atoms that compose all those neurons in my brain that “decide and choose” to walk or sit.
What’s the alternative? That physical events can happen without prior and sufficient cause? That seems immediately wrong because it would limit regularities in the world, make laws capricious, obviate science.
Where then free will? Can nonphysical spirits or souls be saviors? That’s what most theists assume. But spirits and souls have their own problems: How on earth does a nonphysical substance interact with a closed physical world?
What then free will? The question is more fundamental than I’d ever imagined.
To Peter van Inwagen, a philosopher at the University of Notre Dame, free will can be characterized by an appeal to the simple word “able.” If one is able to do this and able to do that, and assuming it is not possible to do both this and that jointly, then one has free will. He defines “determinism” as the thesis that the past up to a given moment determines the one unique way that the world is going to go on after that moment. If one takes together all the laws of nature or physics, such as the conservation of energy, gravitational laws, electromagnetic laws, and the like—the real, deep, underlying, most fundamental laws—the metaphysical thesis of determinism, given those laws, allows only one possible future that is consistent with the way things are at present. One is not able to do this or that. So it seems that free will isn’t compatible with determinism.
If determinism isn’t compatible with free will, van Inwagen continues, the implication is that we’re able to do only exactly those things we do. Of course, we have the strong conviction that we could have done other things, that we were able to do things other than those that we did, but, if determinism isn’t compatible with free will, that conviction must be misleading, and free will must be an illusion.
Van Inwagen frames the free will problem provocatively: Free will is either incompatible with determinism or it’s compatible with determinism—and you can prove both propositions wrong! Now, suppose that free will is both incompatible with determinism and incompatible with indeterminism. Since determinism and indeterminism are the only two possibilities, free will is now incompatible with every possibility, so it’s impossible. But, van Inwagen concludes, “it would be a greater mystery if there were no free will.”
Since determinism is the case in which every event is caused completely by a previous event, is determinism compatible or incompatible with free will? This is the critical question.
My first feeling was: No, determinism cannot be compatible with free will.
But then what?
No determinism? What then the physical world?
No free will? What then our intuition?
Free will seems simple, but the more one thinks about it, the more complex it becomes.
John Searle, a leading philosopher of mind at the University of California, Berkeley, calls the problem of free will “something of a scandal in philosophy.” As Searle puts it, “The reason that we have a special problem about free will is that we have inconsistent views, each of which is supported by what are apparently overwhelming reasons. The reason for believing that we have free will is we experience it every day. We have the experience of conscious, rational decision-making, and we have the experience that the decisions were not themselves forced by antecedently sufficiently causal conditions. We can’t shake off the conviction of free will.”
But on the other side, Searle continues, “we’ve got an overwhelming amount of evidence that everything that happens has an explanation in terms of causally sufficient conditions.” In the natural world, in principle, we can always tell a story or explain a mechanism for why things happen the way they do, and since “human behavior is part of the natural world, it looks like it ought to be explained in terms of causally sufficient conditions.”
Searle states that not only are the two assertions, free will and determinism, incompatible, but “it’s hard to see how we could give up on either of them.” We can’t kill off either one. We’re stuck with both. And they’re not compatible. That’s the mystery.
Free will is no mystery to Daniel Dennett, the distinguished philosopher at Tufts University. Nor is he disturbed by arguments that free will and determinism are not compatible.
First of all, Dennett asserts that “for 2,000 years or more, people have been looking in the wrong place. They’ve been looking at physics, determinism and indeterminism in physics. They should have been looking at biology because the key to free will is recognizing that free will is a biological-level phenomenon. It’s not a physics-level phenomenon. We are freer than our parts. Our parts don’t have free will. But we do.”
But how could that possibly be, without adding something novel, something mysterious? How can free will be made compatible with determinism?
Dennett’s move is not to show that our actions aren’t determined, but rather to show that our actions are not inevitable.
Say what? It would seem that if the future is determined it is inevitable. So what does Dennett claim the word “inevitable” adds?
Dennett says “inevitable means unavoidable.” So then we have to understand what “avoiding” is, he says, which brings in the biological dimension. “Because what’s happened on this planet over the last 4 billion years has been an explosion of avoiding: avoiding dissolution, avoiding being eaten, avoiding starving to death. What evolution has done is designed organisms that do avoiding. How do you avoid something? By anticipating it and then taking corrective measures. Simplest case: incoming brick. You see it, you duck: You avoid it. But suppose you were determined to duck. Well then the brick was never going to hit you. It just seemed as if it was going to hit you. What we have to understand is that free will is our capacity to see probable futures, futures that seem like they’re going to happen, and see them in time to take steps so that something else happens instead.”
Dennett adds that while “you can’t change the past, you can’t change the future either. But what you can do is change what you thought the future was going to be into something else, even though it’s all determined. Biological creatures are determined by the evolutionary process to become better and better avoiders.”
In trying to understand Dennett’s argument, I suggested that his definition of free will seemed impoverished, at least compared with conventional descriptions. He agreed: “I think we have to recognize that there are varieties of free will.” As for “the traditional varieties,” Dennett says, “who cares whether we’ve got them?” The varieties of free will “worth wanting,” he states, are “perfectly compatible with determinism.”
So Dennett’s determinism erodes some of the comfortable notions of “free will” because everything we do is “determined” by the underlying physics of our brains and its environment. Even so, Dennett says, because biological creatures have learned how to avoid bad things, nothing is “inevitable.”
All is determined? But not inevitable? I’ll have to ponder that.
Maybe we’ve pushed philosophy as far as it can go? I check with some other friends.
Psychologist Susan Blackmore, a former parapsychologist turned active skeptic, argues that “there can’t be free will in the traditional sense. When you see how the brain works, how information flows through the brain, there’s no place for free will. So let’s give up on it!”
California Institute of Technology brain scientist Christof Koch, a pioneer in discovering the neural correlates of behavior, says, “I’m ambivalent about free will. Right now, I don’t see how in a physicalist [purely material] universe, free will can survive. On the other hand, I have this profound feeling of free will.” According to Koch, “Almost by definition, if you’re not a dualist, physicalism is all there is: All that exists are space and time, energy and mass and fields of force, which means, of course, there’s no free will. If you’re not a dualist, I do not see where free will could come from because there’s nothing else except blind chance and necessity.”
What do I think? 1) My will is fully free. 2) Free will is not an illusion. 3) Free will is not compatible with determinism. If I cannot do otherwise, no matter the philosophical maneuverings, I’m sorry, my will is not fully free.
What would it take for my will to be fully free? Nothing less than a causal “gap” across which prior physical forces could not leap, at least not with absolute certainty. Somewhere the chain of deterministic events must be broken. It only takes one place.
But that, too, seems impossible because the entire universe is a closed physical system. What about the appeal to the random uncertainty of quantum mechanics, a popular if superficial free-will escape clause. That doesn’t seem to help—even if meaningful quantum computations could occur macroscopically in the hot, wet brain. After all, how could random uncertainty generate free will?
Is there no solution? After analyzing the arguments, van Inwagen, a savvy and sophisticated and not shy philosopher, concludes, “I regard free will as a complete mystery.”
For just this reason, the problem of free will takes us closer to truth.

Robert Lawrence Kuhn speaks with Peter van Inwagen, John Searle, Daniel Dennett, Susan Blackmore, Christof Koch, and Alan Leshner in “What Is Free Will?” the 23rd episode in the Closer to Truth: Cosmos, Consciousness, God TV series, which airs Thursdays on the PBS HD network and many other PBS stations. Every Friday, participants in the series will share their views on the previous day’s episode.

From J. Richard Gott, cosmologist and professor of astrophysical science at Princeton University:

As I wrote in my book Time Travel in Einstein’s Universe, a black hole is a hotel where you check in but you don’t check out. Once you cross the event horizon surrounding the black hole, you have crossed a point of no return, and you cannot get back out. The escape velocity at the event horizon is equal to the speed of light and, since nothing can travel faster than the speed of light, nothing that has gone in can get out. If you fall into a non-rotating black hole, tidal forces will tear you apart as you approach the singularity in the center. But your time of torture is brief. The time from when the tidal forces start to hurt you until you are completely shredded is only 0.08 of a second. That’s independent of the mass of the black hole.
The largest black hole we have found so far is one of 3 billion solar masses found in the center of the galaxy M87. From the time you cross its event horizon until you reach the center would be about 5.5 hours. For a rotating black hole—and the black hole in M87 is surely one of these—the situation is more complicated. The exact solution to Einstein’s equations of general relativity for a rotating black hole shows a ringlike singularity at the center that can be avoided and a region of time travel trapped inside the event horizon, where you could meet your future self and perhaps then pop out into another universe. But there is no coming back to visit your friends in this universe to brag about your adventures. It seems likely, however, that a singularity will develop, blocking your way to these interesting regions. If this singularity is weak, then you might be able to pass through it—like going over a speed bump—and get into the interesting time-travel region and escape to other universes. If the singularity is strong, you will be torn apart before being able to do any time travel. To understand which will occur, we may need to understand quantum gravity—how gravity behaves on microscopic scales. This is one of the reasons the problem is so interesting.
In 1974, Stephen Hawking showed that particles and anti-particles being created out of the vacuum in the vicinity of the event horizon (one falls in, whereas the other, just outside the event horizon, escapes) cause the black hole to radiate thermal radiation (now called Hawking radiation). This Hawking radiation causes the black hole to slowly lose mass and eventually evaporate completely. This is a very slow process. The black hole in M87 will take more than 10⁹⁴ years (that’s a 1 with 94 zeros after it) to evaporate.

J. Richard Gott appears with Kip Thorne, Nima Arkani-Hamed, Juan Maldacena, Lee Smolin, and Leonard Susskind in “Why Black Holes Are Astonishing,” the 22nd episode in the Closer to Truth: Cosmos, Consciousness, God TV series, hosted and created by Robert Lawrence Kuhn. The series airs Thursdays on the PBS HD network and many other PBS stations. Every Friday, participants will share their views on the previous day’s episode.

From Richard Swinburne, emeritus Nolloth Professor of the Philosophy of the Christian Religion at the University of Oxford:

The existence of pain and suffering and other forms of evil is the strongest argument against the existence of God. God is supposed to be omnipotent and perfectly good. But, being omnipotent, he could remove all the evil from the world; and being perfectly good, he would surely seek to do so. So, the argument concludes, there is no God.
However, God’s omnipotence is only supposed to be the power to do anything that is logically possible to do—so, for example, he cannot make me exist and not exist at the same time; he cannot do the logically impossible because it makes no sense to suppose he could. And a perfectly good being may well allow evil to occur if that is the only way this being could promote a great good. So God may well allow evil to occur if, without allowing the evil to occur, it is not logically possible for him to promote some great good.
Much of the evil in the world is caused by the actions of human beings, who cause it deliberately or allow it to occur through negligence. Given that humans have free will, it is not logically possible for God to allow humans to choose whether or not to cause or allow evil and yet ensure that they always choose not to. And it is a great good for human beings to be responsible for each other. You can only really be responsible for someone if it is within your power to give that person either a good life or a bad life; if God had given you only the power to determine what kind of good life came to somebody else, it wouldn’t really matter what you did. But isn’t it hard on the other person, who is thus dependent on you?
Not necessarily. Suffering provides a great opportunity in how one chooses to cope with it—either by feeling sorry for oneself or by showing patience and courage. Each good choice we make makes it easier to make a good choice the next time, and each bad choice makes it easier to make a bad choice next time. Therefore, our actions are not merely good or bad in virtue of their immediate effects on others but also in virtue of their effects on our own character. Obviously, not all evils are caused or allowed by humans; there are the evils caused by accidents and diseases that are currently unpreventable by humans. Yet without these, we could argue, humans would have relatively little opportunity for character formation.
So, the religious defense against the problem of evil is that evil provides great opportunities for free and responsible choice and character formation that would otherwise not be available to us. Of course, God would be mad to cause endless evils in order to give us endless such opportunities. And if there is a God, that’s not what happens. Only for the limited period of our earthly life are there such opportunities, but with them we can form a character suitable for another life.

Richard Swinburne appears with Quentin Smith, Michael Tooley, Alvin Plantinga, and Peter van Inwagen in “Does Evil Disprove God?” the 21st episode in the Closer to Truth: Cosmos, Consciousness, God TV series, hosted and created by Robert Lawrence Kuhn. The series airs Thursdays on the PBS HD network and many other PBS stations. Every Friday, participants will share their views on the previous day’s episode.

From Robert Lawrence Kuhn, host and creator of Closer to Truth:

What are we? What’s the relationship between the thoughts in our minds and the brains in our heads? Is mind stuff different from brain stuff? Or is there something special about mental activity that’s not crammed into craniums? Something special that makes us human? Something non-brain? Something nonphysical?
These questions compose the “mind-body problem,” which has enticed philosophers for centuries (and beguiled me for decades) and touches all we know and do as human beings. I thought that getting a doctorate in brain research would help me figure it out. I’m not sure it did.
To frame the mind-body problem, I start with John Searle, a renowned philosopher of mind at the University of California, Berkeley. Searle critiques both standard solutions—materialism (all thought is reduced to brain) and dualism (mind is totally different from brain). He says both materialism and dualism are “trying to say something true—it’s just that they both end up saying something false. And the trick is to try to preserve the true part …. The materialist says, ‘Reality is ultimately physical particles and fields of force.’ That’s right. But then the materialist denies the irreducibility and existence of the mental. The dualist grants the irreducibility and existence of the mental, but then says it’s ‘not part of the physical world.’ That’s wrong. Most philosophers are materialists of some kind or another because they just think dualism fails.”
Searle’s position is clear: Consciousness is real and based entirely on the brain, and once we learn enough about the brain, we will know everything about consciousness. I know something about the brain, but I cannot yet imagine how knowing even a whole lot more would explain our inner sense of consciousness.
Ned Block, formerly at the Massachusetts Institute of Technology, now at New York University, draws an analogy: “Consciousness is like water. It has a biological essence. So the mind-body problem for consciousness is one where the question is: What is the biological nature of the mind? The mind-body problem for thought and other aspects of cognition likely turns out to be mainly functional; it’s a matter of how thought, how representations in the mind, function so as to produce thinking.” As to what happened to the postulation of the “Identity” solution—that is, that the mind is wholly equal to the brain—Block states, “The problem is the explanatory gap: how it could be that the neuro basis of a given phenomenal state is the neuro basis of that state as opposed to some other phenomenal state or no state at all. We don’t understand that, and furthermore, we don’t even see how we could understand it.”
With all I know about the brain, I can imagine explaining expressions or outputs of consciousness but never its inner sense or feeling.
Some would say that I’m looking in the wrong direction. Traditionally, almost everyone assumed that human beings had a nonphysical soul. The soul was the real you, a position most philosophers now reject.
Not J.P. Moreland, a Christian philosopher, who claims that the “fundamental questions about the nature of consciousness and whether there is a soul are just not scientific questions; they’re questions like, what is a thought? What is a semantic meaning? There has never been a single discovery in neuroscience or any other branch of science that a dualist—that is, one who believes in a soul—could not easily accommodate within his or her theory.”
Moreland goes on to argue, “There are things true of conscious states that aren’t true of physical states, so they can’t be the same thing. Thoughts are either true or false, but no brain state is either true or false. A thought can’t be located close to my left ear, but the brain state that’s going on while I’m having a thought is located in a region of the brain. The brain state has a shape and a size, but the thought itself doesn’t. Thoughts have internationality—they are about things—but no material state of the brain is about anything. One more example: There is a what-it’s-like to be conscious. There is a what-it’s-like to feel pain, a what-it’s-like to see red. What-it’s-like is not something that can be captured in the language of physics, chemistry, or neuroscience.”
As for the neural correlates of consciousness, Moreland gives this analogy: “Suppose that I were in an automobile and I was trapped in the driver’s seat with a seat belt and I couldn’t get out. My ability to drive around town would depend on whether the car was working; if the car broke down, I wouldn’t be able to move. That wouldn’t prove I was the car. That would simply prove that I am functionally dependent upon the car when I’m in the car. So I think that neural scientific correlations are exactly what the dualists would expect.” Correlation and identity are not the same.
I’d love to see the soul exist, solve the mind-body problem—and get a shot at immortality as a kind of bonus. But if it’s that simple, and that important, why doesn’t everyone get it?
Marvin Minsky certainly doesn’t get it. He’s a pioneer of artificial intelligence and argues quite the opposite: that what we call the mind is entirely the output of the biological machine we call the brain. When I tell Minsky that many believe that there’s something extra, some soul, that we need to introduce or inject to make human consciousness—that we need to marry some sort of a nonphysical thing with a physical thing—he responds with indignation: “That sounds just plain silly because how does a soul help? Unless you tell me what are a soul’s parts and how they work, you haven’t answered anything. All you’ve done is provided a word to keep you from thinking about a hard question. When you think you see ‘redness,’ there isn’t any redness. There’s a very complicated process that goes on in many different parts of the brain when you see red. People who talk about a soul are just people who are too ignorant or unambitious or lazy or faith-ridden—I don’t know what insults to hurl at them ….”
To Colin McGinn, a University of Oxford philosopher teaching in the United States, the mind-body problem is a profound mystery. McGinn is so passionate about the depth of this mystery, he is called a “mysterian.” He claims that consciousness “has a nature which makes it really different from the brain …. What is it about the brain which explains why the brain and only the brain gives rise to this phenomenal experience that we call consciousness?”
McGinn rejects brain complexity as a solution for two reasons. “First,” he says, “lots of things are very complex, and yet those things don’t have lower degrees of consciousness. The kidneys are less complex than the brain; do kidneys have a degraded or lower form of consciousness? There’s no reason to think that. So why should the mere number of connections between neurons generate consciousness? We’re moving from one kind of thing to another kind of thing, and complexity doesn’t seem to breach the gap at all …. As far as we can see, within the conceptual scheme that we have now, which has worked so well with the empirical world, nothing removes the mystery.”
Lest there be misunderstanding, McGinn adds quickly, “But that doesn’t lead me to any position which postulates a purpose of the universe or anything of the kind because my explanation for why consciousness is so baffling to us is a resolute naturalistic explanation. It arises from the fact that our own intelligence has been evolved, has evolved as an adaptation, and has the kind of limits that any intelligence or any species on the planet has.”
To me, here’s what’s odd: all these distinguished philosophers, each with a different solution to the mind-body problem. Not just “different.” Radically different! To some, our mind is just our brain. To others, we need a soul. To others still, we don’t even need a brain—any good machine could do. Finally, some say consciousness is such a mystery that it may remain forever so.
Such divergence is not the way of science, especially with increasing knowledge about the brain. What’s going on?
Perhaps this paradox is a type of clue? Perhaps the answer is of a different kind?
The mind-body problem, ages old but perennially new, leads us … closer to truth.

Robert Lawrence Kuhn speaks with John Searle, Ned Block, J.P. Moreland, Marvin Minsky, Alva Noë, and Colin McGinn in “What Is the Mind-Body Problem?” the 20th episode in the Closer to Truth: Cosmos, Consciousness, God TV series, which airs Thursdays on the PBS HD network and many other PBS stations. Every Friday, participants in the series will share their views on the previous day’s episode.