Justified True Belief

(●) Free will and determinism cannot both be true, and the best attempts to reconcile them fail. + A father has said something cruel to his fifteen-year-old daughter, and now he is standing in the hallway outside her closed door. He can hear her crying. He could go back downstairs and let it blow over, the way these things usually do. He knocks instead, and when she opens the door he tells her he was wrong. Most of us would call that knock his. It cost him something, it came out of a real decision, and if anything he does this year deserves a little credit, that does. Now suppose a physicist, armed with a perfect description of the world as it stood a thousand years before the man was born and a complete list of the laws of nature, could have worked out from those two things alone that the knock would come, at that door, at that minute. Nothing about the man would be left out of the calculation. His remorse would be in it, and his upbringing, and his temper, and the sound of his daughter crying, each one following from the one before. Was the knock still up to him? The picture has a name. Determinism is the view that the way the world stands at any one moment, together with the laws of nature, fixes everything that happens afterward, down to the last detail. Philosophers have long divided over what determinism would mean for freedom. Compatibilists hold that determinism and free will can both be true, so that a choice can be fixed a thousand years in advance and still be up to the one who makes it. Incompatibilists hold that they cannot. And incompatibilists who also hold that we really are free, and so that determinism is false, are called libertarians, a name that has nothing to do with politics. The incompatibilist's case has a standard modern form, and its author, Peter van Inwagen, put it in three sentences: "If determinism is true, then our acts are the consequences of the laws of nature and events in the remote past. But it is not up to us what went on before we were born, and neither is it up to us what the laws of nature are. Therefore, the consequences of these things (including our present acts) are not up to us." He called it the Consequence Argument, because it turns on what follows from things nobody controls. So the argument defends incompatibilism: if determinism is true, nothing we do is up to us. It is deductive, which means that if its premises are true, its conclusion cannot be false. It is also an if-then. It does not say that determinism is true, and it does not, all by itself, prove that anyone is free. Its whole job is to show that the "if" and our freedom cannot both stand. Who holds what, on compatibilism: - Support: David Hume gave it its classic defense in 1748, and David Lewis gave it its sharpest reply to this argument in 1981. - Oppose: Thomas Reid answered it in 1788, and Peter van Inwagen gave the argument its modern form in 1983. The argument that follows refutes it.

(P1) If determinism is true, the distant past and the laws of nature guarantee every choice. + This premise does no more than spell out what determinism says, in terms any determinist would accept. (1) Determinism leaves exactly one way for things to go. - On the determinist's picture, the state of the world at any moment, taken together with the laws of nature, is enough to fix every later moment. Given how things stood and how the world works, only one future could follow. - Think of it this way: a row of ten thousand dominoes was set up and tipped over long before you were born. Every tile falls because the one before it fell, and your choice this morning is the ten-thousandth tile. - "Guarantee" means more than "make likely." It means that, with the past as it was and the laws as they are, every other choice was ruled out. (2) Determinism is not fatalism. - Fatalism is the idea that some outcome will come about whatever you do. The oracle tells Oedipus that he will kill his father, and every step he takes to escape the prophecy carries him toward it. - Determinism says nothing of the kind. It does not say that your deliberation, the weighing up of what to do, is bypassed. It says your deliberation is one of the dominoes: it happens, it matters, and the outcome runs straight through it. - So on the determinist's picture the father's remorse is no bystander. It is part of the chain that ends in the knock. The question is not whether his remorse did anything, since plainly it did. The question is whether he had any say in the chain that produced the remorse. (3) The guarantee reaches back before anyone was born. - Determinism does not stop at yesterday. If the state of the world yesterday fixed today, then the state of the world a thousand years ago fixed yesterday, and so fixed today as well. - Take a man called John, sitting in a meeting, who keeps his hand down when the vote is called. If determinism is true, there is no possible history that begins where ours began, obeys the laws ours obeys, and ends with John's hand in the air. Every way things could have gone from that same past, under those same laws, has his hand staying down. - So the guarantee does not depend on the recent past, which John might have had a hand in shaping. It runs from a past that was over and done with before there was any John. (4) A decree can do the guaranteeing as well as physics can. - Determinism is usually pictured as physical, the motion of particles fixing the motion of particles. There is also a theological version, called theological determinism. On it, God decreed before the foundation of the world exactly what each person would choose, and the decree is enough to fix the choice. - Think of the difference between a river and a canal. The river's course is fixed by the slope of the hills, and the canal's course is fixed by the engineer who dug it. Either way, the water has only one place to go. - The argument runs the same way on either version. A decree issued before you existed is part of the distant past, and if it guarantees your choice, it plays exactly the part the world of a thousand years ago played in the physicist's calculation. • Christians who hold that God is outside time would put it a little differently. The decree does not come before your choice on the calendar, they would say, but it does come first in the order of dependence: your choice depends on the decree, and the decree does not depend on your choice. That is all the argument needs, because what matters is which way the dependence runs (P2). (5) The premise does not claim that determinism is true. - It is a conditional, an if-then. It says what determinism would mean, and it takes no position on whether the world is like that. - For what it is worth, physics has not settled the question. Quantum mechanics, the physics of atoms and the particles inside them, is usually read as indeterministic: on that reading, nothing in the past fixes the moment a particular radioactive atom will break apart. There are deterministic readings of the same physics too, and no experiment has yet told them apart. None of the argument depends on which is right. Therefore, if determinism is true, the state of the world long before you were born, together with the laws of nature, guarantees every choice you make.

(P2) Nobody has any say in what happened before he was born. + The past is closed to everyone, and the time before your birth is closed to you twice over, because you were not there. (1) You have a say in a thing if something you could do might make it different. - You have a say in something when there is at least one thing open to you which, if you did it, might leave that thing different from how it is. That is all the phrase means in ordinary speech, and all it means in the argument. - Think of it this way: you have a say in whether the porch light is on tonight. You have no say in whether it rained in Rome on the day Julius Caesar died. - Nothing grand hangs on the words. Having a say is the everyday mark of a thing's being up to you. The father could have gone back downstairs, and that open door is how we usually recognize the knock as his. - It is not the only mark, and it is not the deepest. Deeper still is that nothing but the father settled which way he would go, so that he himself was the source of the knock. Under determinism that mark goes too, since the knock was settled before he existed (C1). (2) Nobody can change the past. - This is common ground in the whole debate, and it is common ground everywhere else too. No one can bring it about that the Titanic missed the iceberg, however strongly he feels about it. - The reason is not a lack of power, the way a man may lack the strength to lift a piano. It is that the past is already fixed, and there is no longer anything to be done about it. (3) Before you were born there was no you to have a say. - Some past things you once had a say in. You had a say in yesterday's lunch, yesterday. The argument does not rely on those. - It relies on the stretch of time before you existed at all. Your grandparents' first meeting, the weather over the Atlantic in 1850, the eruption that buried Pompeii: none of these was ever up to you, not even at the time, because there was never a moment when you could have done anything about them. - That is why the argument reaches for the remote past rather than the recent one. It does not need anything controversial about the past. It needs only a time before you were born, and every one of us has one. (4) A true "what if" about the past gives you no say in it. - The most careful reply to this premise starts from a sentence that really is true. Under determinism, with the laws held as they are, a different choice would have needed a different past. So had you chosen otherwise, the past would have been otherwise, and the reply takes that to mean you have a say in the past after all. • A sentence of that kind is a counterfactual, an if-then about what would have happened had things gone differently than they did: "if I had left five minutes earlier, I would have caught the train." - Now take a sentence about the weather. "If the driveway had been dry this morning, it would not have rained last night." That is true as well, but nobody concludes from it that by drying the driveway with a towel you could have kept last night dry. The sentence runs backward, from something later to what must have come before it, and philosophers call sentences like it backtracking counterfactuals. All it reports is that the wet driveway depends on the rain, read from the driveway's end. - The sentence about your choice is the same kind. Under determinism your choice depends on the past, and "had you chosen otherwise, the past would have differed" reports that dependence from the far end. It tells you which way the dependence runs: from the past to you, never from you to the past. - The if-then that measures a say runs forward instead. It keeps the earlier world as it was, apart from anything in it that itself depends on what you do, and asks what would follow. "If I flip the switch, the porch light will come on" is that kind of sentence. That is why it tells you about your say in the light, while the driveway sentence tells you nothing about any say in the rain. (5) A fact that waits on your choice is different from a fact your choice waits on. - Think of it this way: next week's paper will carry a review of tonight's play. The review waits on how the actors perform tonight, since a better performance would have meant a better review. The script they perform from does not; it may have been written before any of them was born. A decent actor has a say in the review. No actor has a say in a script written before he was born. - So there is one kind of fact, dated before your birth, that you can have a say in after all, and it is the review's kind. What God knew before you were born about what you would do today is really knowledge about today. It is there because of what you will do, and had you been going to do otherwise, God would always have known that instead. The knowledge waits on you, and so it is in your hands exactly as far as the choice itself is. • Christians who hold that God is outside time would say he knows your choice rather than foreknowing it. The point holds the same way, since knowledge from outside time waits on the choice as surely as foreknowledge does. - Under determinism, the world before your birth is the script. Your choice happens because of it, and not the reverse: your choice waits on it. - The same grammar, "had you done otherwise, it would have been different," fits both God's knowledge and the world of a thousand years ago, so the grammar is no guide. What separates them is which way the dependence runs, and only the review is the kind of thing a say can reach. - Nor is the world before your birth the only script. Anything your choice waits on, which does not in turn wait on your choice, may lie before your birth on the calendar, or come before your choice only in the order of dependence, as a decree issued from outside time would (P1). Either way it is script, not review. Therefore, nobody has any say in how the world stood before he was born.

(P3) Nobody has any say in what the laws of nature are. + The laws of nature are the rules the world runs by, and nobody gets to amend them. (1) A law of nature is a rule the world does not break. - A law of nature is not like a speed limit, which a driver can break and be fined for. It is a pattern the world never departs from: that energy is neither created nor destroyed, that nothing outruns light, that a dropped stone falls. • A law in this sense is more than a summary of everything that happens, past and future, much as a mold is more than a list of the castings that come out of it. The view that laws are only such summaries is a serious one, and (D12) takes it up. - Think of it this way: you can jump as hard as you like, as often as you like, and you will come down every time. Nothing about your effort or your wishes enters into it. (2) Nobody can do anything that would break a law. - This too is common ground in the whole debate. Nobody thinks a man can do something that would itself be a violation of the laws, or would cause one. - A man who wished he could be in two places at once has a wish and no say. So does a man who wished that water ran uphill, or that the speed of light were a little faster, so that his radio messages to a probe on Mars would arrive sooner. (3) The most careful compatibilist reply claims something weaker. - The best reply grants all of that. Nobody can break a law, it agrees, or do anything that would cause one to be broken. What it says instead is subtler, and it is easiest to see with John and the vote (P1). - Under determinism, John's keeping his hand down was guaranteed by the past and the laws, so if he had raised it, something in that chain would have had to be different. The reply says the difference would have come a split second before: a tiny departure from the actual laws, so small that no one would notice, after which everything ran on as usual. What we now call a law would not quite have been a law. • Philosophers call that tiny departure a local miracle, though the word is used in a special sense and nothing supernatural is meant by it. - John would not work that miracle, and he would not cause it. It would simply be part of how that other history went. So the reply's claim, put generally, is this: you are able to do something, and had you done it, a local miracle would have happened first. - In the terms of (P2), that is a say in the laws. There is something you could do which, had you done it, would have left the laws not quite what they are, and so the reply denies (P3) as it stands. - This is a clever move, not a silly one. It separates being able to break a law, which nobody can do, from being able to act in a way that would have gone with a slightly different law, which the reply calls harmless. (4) Everybody agrees why Luke cannot go outside. - Meet Luke. He suffers from agoraphobia, an anxiety disorder in which open or public spaces bring on overwhelming dread, and his is severe. He cannot bring himself to choose to go outside. Yet his legs are fine, the door is unlocked, and if he chose to go outside, he would. - Everybody agrees Luke is unable to go outside, and everybody explains it the same way. He can go outside only if he chooses to. He does not choose to, and nothing he could do would make him choose to, because the phobia settles that. So he cannot go outside. - That explanation runs on a principle everybody uses. You cannot do a thing when three conditions all hold: • you can do it only if something else happens; • that something does not happen; • and nothing you could do would make it happen. - All three are needed, and the middle one is easy to overlook. You can catch the 8:15 only if it runs on time, and nothing you could do would make it run on time. But on the mornings it does run on time, you catch it, so without the middle condition the principle would say you never could. (5) That weaker ability would let Luke out the door. - John meets all three of the principle's conditions. He could have raised his hand only if a law had been broken just before. No law was broken. And nothing John could do would break one or cause one to be broken, as the reply itself grants. By the principle, then, John could not have raised his hand, and the reply says he could. Something has to give, and what the local-miracle reply gives up is the principle. - Once the principle is gone, it no longer follows that Luke cannot go outside either. The reasoning that frees the determined man frees Luke just as well, unless something else explains why Luke is stuck. And nobody believes Luke is free to walk out the door. - So the reply owes an account of the difference. Why does the phobia that fixes Luke's choice take away his ability, when the past and the laws that fix everyone's choices take away nobody's? (6) The search for that difference has not succeeded. - The most serious attempt says that an ability is a kind of disposition: a standing readiness to do a thing if you try, rooted in your own inner makeup, the way a wine glass is fragile even while it sits safely on the shelf. On this account Luke lacks the ability to go out because the phobia is part of his makeup. A determined man keeps his ability, because the laws of nature are not part of anybody's makeup. - The trouble is where the phobia sits. It does not touch Luke's legs, or his eyesight, or his knowledge of the way to the shops. It touches only the choosing. He can have every inner property he would need to carry out the choice to go outside, if only he could make it, and still be unable to make it. - Think of a concert pianist whose hands are perfect and who has played the piece a thousand times, frozen in the wings by stage fright. Everything she needs in order to play is intact, except the one thing that settles whether she walks on. - So the account is left with two bad options. It can look at the powers she would use in playing, find them all in working order, and call her able to play tonight, which is false. Or it can find her unable because something she has no say in settles what she will choose, and that reason applies just as well to a choice fixed by the past and the laws. Therefore, nobody has any say in what the laws of nature are, in the same sense in which Luke has no say in whether he goes outside.

(P4) Nobody has any say in what is guaranteed by things he has no say in. + Having no say travels: if you have no say in some things, and they guarantee a further thing, you have no say in that further thing either. (1) Everybody relies on this principle every day. - Philosophers call it a transfer principle, because it transfers a lack of say from one thing to another along a chain of guarantees. - "Guarantee" means here exactly what it meant in (P1): given the things you have no say in, every other outcome is ruled out. - Think of it this way: nobody has any say in the orbit of the moon or the laws that move the sea, and together they guarantee that the tide at Brighton will be high at twelve minutes past four this afternoon. So nobody has any say in whether the tide at Brighton is high at twelve minutes past four. - The same principle is at work whenever a court accepts that someone could not help what he did. The man in handcuffs had no say in the handcuffs, the handcuffs guaranteed that his hand stayed down, and so he had no say in whether it stayed down. (2) It is the same principle that keeps Luke indoors. - Look at Luke again, and the transfer principle is exactly what explains his case. Luke has no say in whether the phobia holds him, and the phobia guarantees that he stays in, so he has no say in whether he stays in. - So the principle is no invention of the incompatibilist. It is the ordinary way anybody explains why somebody could not have done something, and the compatibilist uses it as readily as anyone else, every time he excuses Luke or the man in handcuffs. (3) The principle as first stated had a hole in it. - The hole was found through a counterexample, a single case that shows a general rule to be false, and the case has no determinism in it at all. A coin sits in your pocket all day and you never take it out. Because you never toss it, it does not come down heads, and it does not come down tails. - The first version of the principle counted a thing as out of your hands whenever nothing you could do would make it otherwise. By that count, the coin's not coming down heads was out of your hands. Even had you tossed it, you could not have made it land heads, since which face came up would not have been up to you. For the same reason, its not coming down tails was out of your hands too. - Now take those two facts together. Between them they guarantee a third: the coin came down neither way. So by the first version of the principle, you had no say in that either. But you did. It was the one thing in the story that plainly was up to you, because you could have tossed the coin. - The principle's own defenders granted that the counterexample works against the version first stated, and they mended it. (4) The mended principle counts "no say" strictly. - The repair is to count a thing as one you have no say in only when nothing you could do would so much as risk its being otherwise. By that test you had a say in the coin's not coming down heads, because tossing it would have put heads at risk. So the coin was never a case of having no say at all, and the counterexample has nothing left to work with. - Held to that test, the principle cannot lead from truth to falsehood, and anyone can check why. Picture a valley kept dry by two dams. If nothing you could do would so much as crack either dam, then nothing you could do would so much as dampen the valley. A guarantee works the same way: it rules out every other way for things to go, so the only way to put the guaranteed thing at risk is to put at risk one of the things guaranteeing it. - Nor do the premises about the past and the laws (P2, P3) lose anything under the strict test. Nothing you could do would so much as risk a different world before your birth, or a different set of laws, and the philosophers who deny those premises deny them under the looser test as well (D1, D2). - A second repair, published in 1998, reaches the same place by another road. It never lets the rule put two separate facts together the way heads and tails were put together. Instead it treats the past and the laws as one single thing you have no say in, and carries the lack of say along a single guarantee, from that one thing to your choice. Either way, the known counterexample does not touch what remains. - The repairs are still argued over, as nearly everything in philosophy is. But most of the serious disagreement among philosophers has moved away from this step and onto the premises about the past and the laws, which is where (P2) and (P3) meet it. (5) The principle stops at facts that wait on what you do. - Everybody has to say where the principle stops, or it will carry a lack of say into places where plainly there is a say. It was true a hundred years ago that you would order the fish tonight. It seems you had no say in what was true a hundred years ago, and that old truth guarantees the fish. Run the principle over it, and you never had a say in tonight's order. - The answer is that the old truth is not an independent fact that you have no say in. It is true because of what you will order, and had you been going to order the lamb, it would always have been a truth about the lamb. It waits on you, as God's knowledge of your choice waits on you (P2), and a fact that waits on your choice is exactly as much in your hands as the choice is. - So the fish is no exception to the principle. The principle starts only from things you have no say in, and here you do have a say: wherever the order is in your hands, the old truth is in your hands too. A fact that waits on your choice can never be the independent thing that puts the choice out of your hands. The world before your birth under determinism is not a fact of that kind, and neither are the laws of nature (P2, P3). Therefore, whatever is guaranteed by things nobody has any say in is something nobody has any say in either.

(C1) Therefore, if determinism is true, nobody has any say in what he chooses. + If determinism is true, nobody has any say in what he chooses, and that follows from (P1) through (P4) with nothing added. The same guarantee takes away the source of the choice as well, and with both marks of a free choice gone, nothing anybody chooses is up to him. (1) The argument is a locked chain. - A deductive argument works like a locked chain. If every link holds, the conclusion cannot slip out, and anyone who rejects the conclusion has to say which link breaks. - Walk it through. Under determinism, the world before your birth together with the laws guarantees what you choose (P1). You have no say in the world before your birth (P2), and no say in the laws (P3). What is guaranteed by things you have no say in is something you have no say in (P4). So you have no say in what you choose. - The form is one of the simplest in logic. (P4) is a general rule, (P1) through (P3) show that under determinism your choice meets its conditions, and so the rule applies to your choice. Logicians call that modus ponens: if this, then that; this; therefore that. If the kettle has boiled, the water is hot; it has boiled; so the water is hot. - None of the premises has to be certain. Each has to be more believable than its denial, which is the standard any deductive argument is held to. Deny one and you owe an account of how you have a say in the world before you existed, or in the laws, or how a thing guaranteed by what you cannot touch comes to be in your hands after all. (2) The argument uses "having a say" in its ordinary sense. - A common complaint is that the argument quietly assumes what it sets out to prove, by giving "having a say" some meaning that only an incompatibilist would accept. It does not. It uses the phrase the way everybody uses it about Luke and about the man in handcuffs, and in those cases every side of the debate agrees on the verdict. - What that ordinary sense rules out is the compatibilist's softer reading, called conditional because it hangs on an "if": a man has a say in a thing if he would have done otherwise had he wanted to. Luke would have gone out had he wanted to, and yet he has no say in whether he goes out. - So the argument does not start from a technical definition that its opponent never agreed to. It starts from test cases its opponent already accepts, and argues from them that the determined man is in Luke's position rather than in the position of a man who is free to leave (D3). (3) Under determinism both marks of a free choice fail together. - A free choice has two marks. The first, and the deeper, is its source: the choice was settled by nothing but the person who made it, acting for reasons of his own. The second is the ordinary mark by which we usually recognize the first: the person could have done otherwise, with everything up to that moment exactly as it was. - The two can come apart, and a strange case shows how. Suppose a neurosurgeon has secretly fitted your brain with a device that will switch on and make you keep a promise if you start to waver. As it happens, you never waver. You keep the promise on your own, for your own reasons, and the device never switches on. You could not have broken the promise, so the alternative was gone. Yet the keeping came from you, and nothing but you settled it, so the source was still yours. - Determinism takes both marks, and it takes them through the one guarantee (P1). The ordinary mark goes by way of the chain: nothing you could do would so much as risk the choice's being otherwise (P2 through P4). - The source goes more directly. To settle a choice is to fix which way it will go, and on determinism that was fixed before you were born, by a world and by laws that are not you. Your weighing of reasons is real, and the outcome runs through it. But what the weighing would come to was fixed before there was any you to do the weighing, and nobody settles what was settled before he existed. - Think of the father at his daughter's door. On determinism he did not settle the knock, since the knock was settled a thousand years before him. And he could not have gone back downstairs, since the same thousand years ruled that out. (4) Compatibilists give a rival account of the source. - The compatibilist answers that you settle a choice by deliberating, and that nothing more is needed. On his account a choice comes from you when it flows from your own reasons, weighed by a way of deciding that is your own and responds to reasons, however you came to have them. The past fixed that you would choose as you did, he says, and the choosing was still yours. - (P1) through (P4) do not refute that account by themselves. What tells against it is the argument from manipulation, so called because it sets a determined person beside a manipulated one and asks what separates them. - Picture a scientist who arranged, from the moment of your conception, that your reasons and your way of weighing them would run exactly as they run. Every condition the rival account names would be met, and yet it is hard to see how the result would be up to you. The compatibilist owes a difference between that case and a determined world with no scientist in it, and finding one is the question the argument from manipulation presses (D9, D14). - So the conclusion's two claims stand on different footing. The first, that nobody has any say in what he chooses, follows from (P1) through (P4) alone. The second, that nothing he chooses has its source in him, follows from (P1) together with what it is to be the source of a choice, and the argument from manipulation is where that account of the source is defended. (5) The conclusion leaves open whether anyone is free. - The conclusion is an if-then, like (P1), so it settles neither whether determinism is true nor whether anyone is free. What it shows is that the two cannot both be held. Anyone who is sure that some of what he does is up to him therefore has a reason, and a strong one, to deny that the past and the laws settle everything. - It also says nothing about God's knowing in advance what you will choose. Knowing is not settling, and a belief that waits on your choice is not among the things that settle it (P2, D15). (6) Scripture sets real choices before people. - Scripture sets choices in front of people as though the choice were theirs to make: "Therefore choose life, that you and your offspring may live" (Deuteronomy 30:19), and "choose this day whom you will serve" (Joshua 24:15). - That is why the question matters to a Christian. If determinism were true, how the people who heard those words answered them would never have been up to them. Therefore, if determinism is true, nothing anyone chooses is up to him.