The Impossibility of Proving that Human Behavior is Determined
Dr. Richard Swinburne explains why a theory of neuroscience built on physical determinism is implausible and ultimately unprovable. Dr. Swinburne takes his audience through careful logical scenarios to arrive at his conclusion. Following his argument, two philosophers offer their own comments on Dr. Swinburne’s conclusion.
Thank you very much for inviting me and I will now give you my views on The Impossibility of Proving that Human Behavior is Determined. I hope everyone has a handout because what I’m going to do I’m gonna take you through that handout I’m not going to read out my written paper.
So the issue is could there be a scientific theory which on the basis of our present state on observing what’s going on in our brain at the moment and what our mental life is would be able to predict which intentions we form that is to say what we decide to try to do and so which intentional actions we perform. And I propose to answer that question in the negative that there couldn’t be such a theory. Now to start with a few definitions, they are on your handout. I understand by a physical event one to which anyone can have as much access as anyone else that there is a lectern in this room it’s something you can see as well as I can see and no one if they try hard is in a privileged position with regard to that.
On the other hand I understand by a mental event one to which the subject has privileged access that is to say I know better than you whether I’m seeing a lectern in this room because I have access to what my experiences are in a way that you don’t. The example I gave of a mental event is what I call an impure mental event. An impure mental event is one which the occurrence of which entails a physical event that is to say my seeing a lectern here entails there is a lectern here which is a physical event. But there are also crucially pure mental events that is to say ones which do not entail the occurrence of a physical event.
My seeming to see a lectern here is a pure mental event that doesn’t entail anything about the physical world. And there are I suggest five different kinds of pure mental event. There are sensations. Such as sensations of pain or patterns of color in the visual field feelings of heat and so on. There are beliefs. I believe that today is Friday and these beliefs also include moral beliefs. There are beliefs about this action is the best one to do in these circumstances and so on. And then there are occurring thoughts. It crosses my mind that there are a lot of people here. And then there are desires.
I understand by desires inclinations that we find within ourself to do this or that. I might desire to drink, desire to be prime minister or whatever. And then there are above all intentions. Now as I am understanding intentions someone’s intention by that I mean their intention in what they are doing what they are trying to achieve by what they are doing. Alas my intention in waving my hand is to draw your attention to a philosophical point is what I’m trying to do thereby. So sensations, thoughts, beliefs, desires and intentions.
Okay now if there’s to be a Deterministic theory of human behavior it will be a Deterministic theory of the public intentional actions we perform. And it will have one or two shapes. It will either be what I call an Epiphenomenalist theory or it will be Psychophysical theory. Now by an Epiphenomenalist theory I mean one that explains all our public actions merely in terms of brainy things. It says one brain event causes another brain event causes another brain event eventually causes my hand to move and my intentions, my thoughts, my beliefs make no difference to that. The alternative kind of theory which superficially is certainly more plausible is the Psychophysical theory which says that our brain states which are of course physical events and our mental events interact.
Our brain states influenced a lot by the outside world cause us to have certain beliefs and certain desires and these desires interact in a certain way and they lead to more beliefs. We put some of our beliefs together and get another one and then we have beliefs about what’s best to do and we have a desire about what to do and sometimes these clash and sometimes they don’t and eventually this leads to an intention and the intention causes a brain event which causes a public act.
So there are two possible thoughts that’s two possible kinds of Deterministic theory of human behavior. And I’m going to represent by the Bs brain events and by the M mental events. And when I talk about mental events in future I’m talking only about pure mental events. Now Epiphenomenalist theory says Brain state one causes brain state two causes brain state three causes brain state four leads to hand motion.
I may indeed form an intention to influence the motion of my hand but according to such a theory the intention makes no difference to what happens. The normal explanation of what’s going on by people who favor this theory is that there is as it were a common cause some brain event both of my supposed, my intention to move my hand and of the hand moving and it’s because as a matter of fact these coincide I have an intention to move a hand at the same time as the hand moves. I come to the fallacious belief that the intention is causing the hand movement. But according to the Epiphenomenalist theory it isn’t they just have a common cause. So for the Epiphenomenalist brain events lead to mental events, mental events including primary of course conscious events lead to nothing.
Well that’s a fashionable theory. And so far up till about 1980, nobody really knew what was happening inside the brain but since 1980 various techniques have been invented for finding out what’s happening in the brain when we perform intentional actions. And the first experiment on these matters done in the 1980 by Benjamin Libet has led to a whole genre of innumerable more sophisticated kinds of experiment with more sophisticated ways of finding out what’s going on in the brain. But in order to show what I think is wrong with this kind of experiment I will take the original Libet experiment. Now what Benjamin Libet did, many of you may know this but for those with who don’t I go through the moves what Benjamin Libet did was to get a number of students and sit them at desks.
And in front of each student there was a clock which moved very fast so that it would measure milliseconds not just seconds. And attached to each student’s head there were various bits of electrical apparatus such that they could measure very slight changes in the electric potential at different parts of the brain. And Libet said to the students, “sometime within “the next 20 seconds you are to move your hand. “You are to decide when to move your hand “and it’s going to be an act of free “what you think is free will on your part.” So the students did this and they move hands at various times and they were also instructed to say at what time by their clock exactly did they form the intention.
Now what then Libet noticed is that in each case when a student might form an intention to move his hand the hand movement occurred a little bit later but half a second before the time at which according to the student the student formed the intention to move the hand there was a buildup of electric potential to a certain point on the scalp. And what that showed said Libet is that is it well we were already predetermined to form the relevant intention and formed the relevant intention half a second later.
And as it were those who formed the intentions towards the end of the 20 second the build up of the potential on the scalp only occurred half a second before that. So this seem to suggest that some going on in the brain half a second before the forming of an intention but already set in train a sequence of movements leading to a hand movement and this which occurred half a second after that had no influence on what’s going on. So this seems to support the Epiphenomenalist view.
Now I don’t then think even by the his own standards apart from the point I’m now going to make it did support that view but at any rate it has generated a whole range of very similar kinds of experiments trying to detect the moment at which people form their intentions and trying to show that that didn’t make any difference to what’s going to happen.
Right and this was therefor generalized into the view that this sort of thing makes no difference to this sort of thing. And the suggestion was in fact that therefore as it were not merely this is not influenced things but there’s a pretty Deterministic chain of brain events which does influence things.
Now there is I think a crucial flaw in any generalization of these particular results. I don’t wish to question these particular results but the generalization from that to never do our beliefs, thoughts, purposes, intentions, et cetera make a difference to our action is basically flawed for this very simple reason. It’s crucial for the generalization that the experimenter knows the time at which the intention is formed. I mean if the intention was formed here it wouldn’t show anything so that the intentions formed here then shows that.
Okay so how do we know at what time the intention was formed? Well the students tell us. Why should we believe what students tell us? Well they are pretty honest sort of people of course but why we believe them is because we think they are looking out for this intention and they notice this intention in them and for life and they form the intentional different attention to tell us what their intention is.
And they think the words come out of their mouth because of their intention to tell us the time at which they formed their intention. And if we didn’t think that if we didn’t think as it were the words were coming out of their mouth because they had a certain belief about when they formed the intention we wouldn’t believe what they were telling us. So you will see the obvious consequences. It may be that in this experiment this is not making a difference to that but our only reason for believing this must be because we believe that some other intention to tell us the truth is making a difference to a brain event and what comes out of our mouth. So you can’t generalize this sort of result. You can only believe that this kind of account the Epiphenomenalist account works in a certain area for certain kinds of actions in certain circumstances if you disbelief that it holds generally.
So if you think that it holds generally you wouldn’t have any knowledge of the mental life and therefore you couldn’t show anything by this sort of method. Okay now that’s not the only way in which one can try and prove an Epiphenomenalist theory what is crucial here is we attempt to prove the theory by showing that this sort of thing is uninfluenced by that sort of thing. And we try and show that by showing when this sort of thing the mental event occurs. But there might be another way of showing that these things make no difference without actually knowing what they are or when they occur.
One might devise a theory of Physics which was Deterministic which had the consequence that for every physical event including therefore brain events there was some proceeding physical event which was necessary and sufficient for the occurrence of the later one. And this one would do establish by doing a large number of experiments and getting the simplest account which one could get from those experiments. And that would suggest that nothing but brain events or other physical events make a difference to brain events. So these things can’t make a difference to brain events. And to set up such a theory one doesn’t have to have knowledge of anyone’s mental life one can just observe the brain. Well that looks as if it might work.
But now then in order to establish this theory and to get good predictions from it what we must do we have to know two things first we have to know what the theory predicts and secondly we have to observe that what the theory predicts in fact occurs. Now the trouble is how are we going to know what the theory predicts? Theories of physics are highly complicated things and it takes some time to work out what the prediction of the theory for a particular set up would be.
Well how do you and I know whether some physicist has got it right? Well he tells us, he tells us that his theory has predicted so and so and he’s observed so and so. Why should we believe the physicist? Well physicists try and tell us the truth. They try and tell us that the calculations they have reached in their head or by some sort of observation have the consequence that the theory predicts this. Our reason for believing the physicist is we think it’s clear to the physicist in his mind that that is so and he is trying to tell us what is in his mind. In other words we believe that in this case what his thoughts in his mind are being transmitted to us because he has a belief that he’s proved this and the intention to tell us.
And we believe the words that come out of his mouth because he has the intention to tell us. So once again we, although we may know what’s occurred without there being any downward causation we can’t know that the theories predicted anything without there being any downward causation. At least we non-scientists from outside rely on scientists and to rely on scientists just to rely on what they say about the processes of their mental life and we can’t get that without we can’t believe that without there being downward causation.
Now you may say scientists might do their calculations on paper I’m sure they might but they’ve got to see what they’ve written on the paper in fact it’s got to be clear to them that that in fact shows that the theory predicts this and they’ve got to tell us that theory predicts this on the basis of what they’ve seen and they’ve written on the paper what they have because they’ve worked out something in their head.
So once again there’s two processes of downward causation coming on from their mental thoughts to what’s on their paper and to what they’ve written, what they tell us. And of course you may say well can’t they know how do they know about that their theory is correct even if they can’t tell us without any downward causation. But they need to remember the earlier stages they’ve got to believe that this result they’ve reached they’ve reached because of the earlier stages in their calculation.
And that’s to say they’ve got to remember the earlier stages well and remember they’ve come to this this prediction as a result of calculating from the earlier stages. Now we know that we only remember things because when we have experienced 10 minutes ago this produces some trace in our brain which in turn leads us to remember it. So memory only works because once again there’s a downward causation of the event in our mental life causes a brain state events in our mental life causes the brain state and this enables us to remember later what has happened. So once again you can’t establish you can’t have a grounds for believing an Epiphenomenalist theory unless it makes predictions.
You can only know that it makes predictions if there is downward causation from mental life to brain states. Either downward causation in the sense that the agent tells us what brain events is happening in order to show us theory makes predictions or if the agent has to tell us what the theory predicts in order to show that he’s got it right. And either way we can only believe that the Epiphenomenalist theory works for certain areas if we are prepared also to believe that it doesn’t work in other areas and in particular we’ve got to if we are to have grounds for any such theory of this kind we have to think about what happens in the mental life the conscious life of student subjects or scientists who give us information leads to, causes them to say what they do to us and that the past stages of their calculations caused to them via brain states to remember what they have calculated. And either way they have to believe in a downward causation in order to have any in one area in order to believe that it doesn’t operate in another area.
So any attempt to prove a Deterministic theory of an Epiphenomenalist kind is bound to fail whatever the experimental result that might be produced in a lab tomorrow it simply won’t work because the only reason for believing the experimental result in the lab depends on assuming that Epiphenomenalism is not universally true.
Okay now the reason this theory has failed is because it failed to make predictions because the predictions depend on the assumption the theory is false. Now it’s very important that a scientific theory should meet that criteria. The Scientific theory has another kind of criteria which it ought to meet. That is to say it has to be a simple theory. Now consider some various very ordinary theory of Mechanics that a system of particles interacting, bouncing off each other inelastic particles momentum is conserved if one particle loses a certain amount of mass times velocity the other particle gains a certain amount of mass times velocity.
Right now this theory is a simple theory in the sense that it says in any collision whether it’s between masses of 10 pounds masses of 20 pounds velocities of a 100 miles an hour velocities of 1000 miles an hour exactly the same formula applies. But suppose it were the case that the momentum of subsequent particles depended in a rather more complicated way on the momentum of earlier particles. Suppose there was one law when the earlier particle was of nine kilograms in weight and a quite different law for when it was 10 kilograms in weight such that there was no connection between these laws that say there was a law of momentum for 10 kilogram particles and quite different law say it might be the MV is conserved for 10 kilogram particles but it’s half MV squared that’s conserved for nine kilogram particles and one over MV that’s conserved for eight kilogram particles and so on.
Now if you started to find that was the case you would then have no grounds for making any predictions about anything beyond particles which had exactly those particular masses. And you’d be pretty dubious about those predictions because you would say well there must be some connection between these things and that means that we can’t really rely on this extraordinary law for particles of eight kilograms thus going on forever because clearly this whole system is liable to go wrong at some stage. Okay now my point in making that point is that when we come to a Psychophysical theory we’re going to run into justice problem.
The only possible Psychophysical theory of human behavior is going to have innumerable numbers of different laws which have little connection with each other. So many of them that all right we might be able to predict what would happen to a person who had exactly those brain states beliefs, desires, and so on in the same way another time. But we can’t make any predictions about someone who has a slightly different belief that he didn’t have before or a slightly different desire or a slightly different brain state. Now let me say why if you are to have that sort of theory I’m sorry go back preliminary point.
So we’ve moved on to the suggestion that what’s happening is this roughly speaking certainly brain states might lead to our having beliefs and desires of various sorts. These might interact with each other in the sense that one belief might suggest another one desire might conflict with some belief about what we thought most worth doing and we’d have to decide between them and so on until that all worked up to an intention which we sought to execute. Now sometimes quite clearly we can make and are right to make predictions from someone’s mental life at a time to what they would do.
If somebody has a belief that this kind of action is the best thing to do in this circumstance and he has no desire to do anything else then we can infer from that that he will form an intention to do that thing and he would do it. And if someone has a desire to do a certain action and that’s stronger than his desires to do any other action and no belief about it not being a good thing to do this sort of action then he will do that sort of action. If you know that a certain brain state will cause me to feel thirsty and you know I have no beliefs about it being wrong to drink things and no rival desires you can predict that I will drink.
Okay so there’s obviously going to be a certain amount of determinism you can call it in our behavior. What however is at stake is whether we have a choice when in our view there are two things which we equally desire to do or two things which we think equally best actions to do or above all when we have a choice between what we think best to do and what we desire feel inclined to do between fulfilling our desire for more cream cake as opposed to a belief that it would be bad to do so. In those circumstances clearly what goes on in our mental life the conscious level is not going to determine what we will do.
If anything determines what we will do it will be the interaction with what goes on in the conscious level with what’s going on here all the time they’ll be up and down. Now could you have a theory that would predict what we would do in those kinds of circumstances. Now that’s where the problem starts. These things are measurable things. They are the brain states consist of our brains consists of large number of nerve cells neurons which connect with each other. And what goes on in our brain is a matter of how many connections each neuron has with another connection and how distant it is from the neuron with which it has a connection.
And how often these neurons fire that is transmit electric potential to the next thing and so there are certain measurable features of our brain a fairly small finite kind the location of neurons, the connections of neurons, the patterns of electric charge of neurons. So something nice, measurable and fiscal. What we’ve got at this level is not that sort of thing at all. It’s a belief that it’s a sunny day or that today is Friday or that it’s good to do philosophy and so on. You can’t measure those they can’t be given a number.
One doesn’t have my belief that today is Friday doesn’t have more of some quality or less of some quality than my belief that it’s a sunny day. They’re just different and the differences the only way to articulate the differences is to have a theory of language that says well someone’s belief that so and so amounts to their ability to recognize cases of so and so and their ability to make inferences of such in kind. And there are, it takes a dictionary and a grammar of a language to lay down all the rules for how different mental states differ from each other.
Worse than that everybody has slightly different beliefs which they will publicly articulate by the same words from each other because everybody understands by say just to take one example this is a table something slightly different from what anybody else understands by let’s just say some people count a sideboard as a table some people count a desk as a table other people won’t count those and so on. And okay I’m exaggerating slightly to say everybody has totally shifted from everybody else but many people have rather different, slightly different in their beliefs from anybody else which they will articulate publicly. And therefore if you are to have a theory or even of which beliefs would be produced by a certain brain state.
And the same goes for desires and thoughts and so on you would have to study different individuals and try and see what produce in them by that. But that won’t tell you what will happen in everybody else because they have a different system of concept, slightly different system of concepts and therefore any law if you could ever have one for one individual it can be a bit different from the law you would have for another individual.
And this is brought out actually by a recent psychological work which showed a subject certain pictures it was of implements of certain kind. I might say someone a picture of a hammer and then observe what happens in different parts of the brain in different subjects when they observe the hammer. And generally of course somewhat similar things happened in most subjects when they observed the hammer but never did exactly the same thing happen in every subject and that brought out that we are different because we have different concepts.
If you want to study how our beliefs our brain states cause our beliefs then you’ve gotta have separate laws for individuals so you can’t measure these things on a toll they don’t have a number if you’re just to produce laws for each kind of belief each particular belief that someone might have then you’ve got to make laws different for each individual. If you’re, what we do with these things depends also on the strengths of these things.
It’s the strength of a sensation that makes a difference to whether I, strength of the itch it makes a difference to whether I scratch it or not. And so the beliefs, the sensations and so on have to have strength if we are to calculate what happens. But although we can say when one sensation is stronger than another one what we can’t say is when it’s twice as strong as another one. That is to say we can only give a comparative measurement there’s no sense.
Doctors sometimes ask their patients is this twice as painful as that? Well you have no measure it can’t be done furthermore the whole problem is ruined by the fact that if we are to collect all these data there are certain sort of data that we can’t even possibly collect because we haven’t got a clue what people mean by their statements as their sensation because although you and I might recognize the same objects as green objects and therefor is a green sensation what we don’t know is whether you recognize it as green on the basis of the same sensations as I recognize it as green maybe my sensations are a bit brighter or a bit redder or something than yours.
So the situation is now that we’re just not going to we would have to have enormous numbers of laws differing for each individual connecting measurable things with non measurable things of which there are innumerable measurable things for each individual many of which sorry and even numerable non measurable things for any individuals which will have strengths which again we are unable to measure and which will influence our behavior. Now this doesn’t of course follow from this that our behavior isn’t determined but what does follow is that in order to show that it is we would have to replicate large numbers of experiments in exactly the same circumstances as before.
We would have to well get hold of subjects from birth, put them in rooms without windows, identical twins and then try and ensure that the input to each twin was exactly the same. And then work out whether the response was the same and that’s not gonna happen and even if it did happen there is still going to be a difference because one twin would be in one place and hear one noise louder than the other when one would and still it wouldn’t work.
So conclusion we are never going to be able to have a system of laws which enables us to make predictions about what people would do in different circumstances because we would have to have so many different kinds of laws each of which will only be applicable to persons with certain brain states and certain previous mental life because the effect of one belief on us depends on what the other beliefs have. And therefore you can’t work out what the belief on its own is going to make a difference to.
So we’re just not going to have these laws what we’re going to have is Probabilistic laws people with certain sorts of beliefs and certain sorts of brain states are more likely to do this sort of thing than other people. Okay but that doesn’t show that their behavior is determined it only shows that they are subject to influences which make it more likely that they will do this rather than that. So what are we to conclude from this if we can’t get a Deterministic theory for the reasons I’ve given. Well you might say that doesn’t show there isn’t one.
Well no but note the kinds of things we are unable to predict and I did comment earlier that there are certain things we are able to predict the kinds of things we’re unable to predict or what we will do in circumstances where we have to make decisions between two actions which seem to us equally good two actions which seem to us equally desired and between what we desire to do a above all when there is a decision between what we desire to do and what we feel inclined to do our desires.
And it’s in just those circumstances that we feel that we are making a decision that is we who are making a decision what shall I do in this moral dilemma circumstance which is not what we are deciding. Most of us for most of the day we’re going on an autopilot most of the day and the desires turn up and we shall see we fulfill them on it’s own. And it is an Epistemological principle which I call the principle of credulity that you ought to believe that things are as they seem to be in the absence of counter evidence. You ought to believe that here is a table unless someone can show you it’s a hologram. You ought to believe that it’s sunny outside unless someone could show you that it’s only a picture on the wall and so on.
And if it seems to you that you’re making a decision and nobody can show you you are not it’s reasonable to suppose that you are right about this and therefore I think it is reasonable to believe that we do make decisions which are not influenced fully although of course not determined fully although of course influenced by other mental life and our belief states. Thank you. [audience claps]
I just wanna start by saying that I’ve learned and I continue to learn a lot from you Dr.Swinburne by both reading your books and in person. And I’m personally very appreciative of your continued work and contribution. Now in the paper just presented I’m not completely sure that there is a real challenge that’s been levied against an Epiphenomenalist reading of the kinds of experiments that he talked about.
The Benjamin Libet experiments I’ll call them Libet style experiments and to recap Dr. Swinburne’s argument and he’ll tell us later if I’ve got it wrong. But the first is neuroscientists trust participants self report to turn the mental event of willing or intending to move. And in order to trust the self report neuroscientists must rely on participants judgments. In relying on participants judgements or their own judgments the neuroscientist is making a causal assumption namely that our beliefs and intentions often cause our movements including our vocalizations. Epiphenomenalism undermines this causal assumption thus rendering trust in the participants judgments unjustified.
So to this argument I’m not endorsing this argument but this is what I think an Epiphenomenalist might say is that they might say that a participant’s neuro system is organized and has developed in such a way that they are able to accurately respond and give respond to questions about the time in events mental or physical even though conscious willing or conscious intending is an illusion.
So in this case the causal assumption they’d be making as Epiphenomenalist is the individual report is accurate because even though it’s purely mechanistic and purely neuro and at the same time given what Dr. Swinburne said the Epiphenomenalist may still maintain that the individuals report about the timing of the mental event of willing or of intending to move can be trusted without being inconsistent. And the trust of the neuroscientists would just rest on the evolutionary process the person’s past developmental experiences that have engineered their neuro system in such a way that they’re able to give accurate reports.
Similarly the neuroscientist might further claim that they too have been so engineered and thus claim that they are capable of making accurate judgments about what Libet style experiments show without making the causal assumption that Dr. Swinburne has implied they must make the assumption that intentions cause certain bodily movements and vocalizations.
Having said this I do agree with Dr. Swinburne that Libet style experiments don’t provide evidence that we are not a volunteer intentional agents but I have different reasons. I’m of the position that the design of these experiments and the conclusion that they provide evidence that we are not voluntary agents is predicated on a certain inaccurate volitional theory and roughly the Volitional theory is as follows voluntary and intentional action is bodily motion that has a certain mental event in its causal history and we can be occurrently conscious of this mental event. We are conscious of when it occurs.
So for example Cain’s murder of Abel is voluntary and intentional granted Cain’s body moved in a way that led to Abel’s death and this motion was caused by either a particular kind of conscious mental event or according to a slightly different version by Cain’s performance of a certain mental act. However there’s been another and I believe more accurate account of voluntary and intentional action. I’ll call this account the Aristotle accounts since its contours can be traced back to some of his works.
According to the Aristotle account voluntary and intentional action is a way of exercising a two way power and that is a power to act or not act on a given occasion. I can either act or not act in the awareness of certain things such as what I’m doing and that I’m able to behave differently at this moment. So to return to our example Cain’s murder of Abel is voluntary and intentional because Cain brings about Abel’s death, is aware of what he’s doing and he is aware he could do something other something else and he’s not under duress he’s not being forced and on this account to be aware of what one is doing we’re aware that one is able to do something else it does not correspond with any mental event which one is occurrently conscious of.
We are aware of all kinds of things that inform how we act and think throughout the day without thinking about these things or otherwise directing our mental activities toward them. We’re aware of these things outside the timeframe of any occurrence of any conscious mental event. So bringing to the Aristotle account voluntary so according to their Aristotle account voluntary and intentionally acting is bringing about motion of one’s body in a certain state of awareness. and this awareness doesn’t correspond with any mental event of which we are occurrently conscious and in this case there’s no conscious mental event of willing or intending to be timed in the first place.
Thus the mental event that’s been timed in Libet style experiments is actually some kind of urge, sensation, feeling or thought that can but did not accompany certain actions. At this juncture I’m really wanting to suggest given that we have historically two different kinds of accounts of voluntary and intentional conduct at most we should think of Libet style experiments and this is at most as providing evidence that Evolutionary theory which is just merely one way of thinking about voluntary conduct is inaccurate his experiments should not lead us to think that voluntary agency is all together an illusion.
I’d like to make one final point. I think Dr. Swinburne has provided a convincing argument for why the causal closure of the physical with respect to the relevant neural activities will never be proven. But I think that a die hard causal closurerist might not argue otherwise and this is what I’m think they might argue. I think they might say well we have good evidence from physics and possibly chemistry and biology that everything that happens in the universe can be explained by physical laws. Our brains are part of the furniture of the universe and so we also have good evidence that they too operate according to physical laws.
Given this position the fact that our brains and mental lives are so complex and multi-form so as to ensure that we will never be able to prove that our brains operate entirely according to physical laws is not by itself likely to surprise the causal closures or give them pause. Rather the causal closurerist is likely to argue that the skeptic who thinks that our brains do not operate entirely according to physical laws is failing to apply the lessons learned about the universe to our brains.
Having said this given Dr. Swinburne’s point that it’s impossible to prove that brains operate entirely according to physical laws we might give the causal closurerist pause and make them start to question their initial premise and this is we might make them question their view that there is good evidence that everything that happens can be explained by physical laws and having pointed this out with the time allotted I can do no more than outline a is substantial and sustained argument that has been developed by Nancy Cartwright against the empirical basis for thinking that everything that happens in the universe can be explained by physical laws. Cartwright an influential philosopher of science has used extensive concrete illustrations mostly from physics to make the case the success of our best physics theories supports their truth but not their universality.
She argues that we only have evidence to support the application of the laws of physics to a limited range of circumstances namely the range we consider when we’re formulating those laws and if this is true of physics it’s equally true for other natural sciences. Cartwright argues that when we begin to look at the various laws we have developed the other kinds of laws you would expect of a stratisfied world wherein laws are useful and applicable only under certain circumstances and wherein there may commonly be occurrences that are subject to no law.
As she states the laws that describe our world and I quote, “look like and steadfastly stick “to looking like science as we know it “apportioned into disciplines apparently “arbitrarily grown up governing different sets “of properties of different levels of abstraction “pockets of great precision large parcels “of qualitative maxims resisting precise “formulation,” as Dr. Swinburne pointed out. Periodic overlaps here and there once in a while corners that line up but mostly ragged edges and always the cover of the largest loosely attached to jumbled world of material things. What is happening is more like an outcome of negotiation between domains than a logical consequence of the whole system one system of order.
It may of course be true and that’s another quote, “it may of course be true “that the idea that everything that happens “in the universe can be explained “by physical laws is consistent with “the fact we can and do design “and use laws to explain at least a sector “of what happens in the world. “But we must remember that being consistent with “is not the same thing as being warranted by “or then being the only plausible way “of coming to terms with.”
This is what I’ll say about this topic here it’s enough to bring up the point that thinking there’s evidence that everything that happens in the universe can be explained by physical laws is contentious at best and continues to be a matter of debate amongst philosophers science. Therefore while upholding the causal closure of the physical may be incompatible with upholding the idea we are voluntary agents the grounds for upholding the causal closure of the physical are very tenuous basis for rejecting the idea we are voluntary or intentional agents. Thank you. [audience claps]
So if I had more time than the Jack booted Tom Crisp has allowed [audience member laughs] I could go into greater detail in expressing my gratitude for the work of Richard Swinburne. But as things stand I’ll just say that I am indeed thankful to God for the insight and inspiration that Professor Swinburne’s work has provided me. It’s well known that Professor Swinburne is a distinctively systematic thinker. I admire this aspect of his work enormously.
Not only is it very difficult to achieve the kind of wide and deep integration of argument characteristic of his work such integration also stands to reveal interrelations and dependencies between ideas that would otherwise remain hidden from us. However Swinburne systematicity presents commentators like Jason and myself with a special challenge I think we’re aware that Professor Swinburne’s argument here is as usual embedded in a much larger argumentative context the understanding of which might very well render local complaints odious. So imagine someone maybe like myself who’s largely in the dark regarding the complex interworkings of mechanical watches.
And when this person is shown a particular intricately crafted bit of gearing pulled from the guts of a watch, he may very well be puzzled about how this piece could contribute to timekeeping. In my own case at least I worry that the concerns I’m about to raise might indeed be of this ignorance or to the degree that they are I invite Professor Swinburne to treat them as requests to show us more about his wider project here and the connection between that project and this one that is I invite him to tell us more about timekeeping in general and about the particular watch that this bit of gearing he has shared with us today is a part of.
So I began by noting that the title of his presentation is, The Impossibility of Proving that Human Behavior is Determined and actually there’s three different views about this going on right there’s the one that’s on the advertisement that describes it as The Impossibility of Proving Determinism, his actual paper says The Impossibility of Proving That Human Behavior is Determined then we have this one, The Impossibility of Physical Determinism. I take all of those three thesis to be slightly different. So I’ll be asking for some clarification about that. But strictly speaking that the claim The Impossibility of Proving That Human Behavior is Determined that’s what philosophers in our admittedly technical jargon are likely to call a sexy thesis. I don’t know if I’m allowed to say sexy thesis at Biola in Calvary Chapel [audience laughs] but there it is.
But yeah it’d be a first okay. And just before we got started here JP said to me Dan, don’t embarrass us. [audience laughs] You’re only here two more days. Hold it together. So I may have failed that injunction already JP I’m not sure okay. But what we mean in philosophy by a sexy thesis is one that’s provocative that gets at something important and interesting and then maybe it’s even a surprising but when Swinburne announces his formal conclusion at the very beginning of his talk, the thesis I think loses some of its initial sexiness. There he tells us that the conclusion is something like this, “that it is immensely “improbable that there could ever be “a well justified theory which predicted “with 100% success which intentional actions “humans would do in all situations.”
That’s a quote and the improbability he tells us is going to be due to the fact that quote, “our criteria for a well justified scientific “theory make it almost impossible for “a theory of this kind to be well justified,” unquote so the concerns I’m gonna raise about the argument he presents all have to do with my inability to see just what it could tell us, his argument even if sound about any interesting version of the claim that human behavior is determined. So my brief strategy is going to be to grant Swinburne his conclusion but go onto wonder if anything important about the thesis of Determinism can follow.
So now as far as I can see we haven’t been told what precisely it would mean if human behavior is determined in the way Swinburne has in mind. That is it isn’t clear from what Swinburne has told us here either what the relevant concept of Determinism is supposed to be or what the consequences for human behavior would be if this kind of Determinism turned out to obtain. So one thesis of Determinism that’s likely to jump immediately to mind is the one ordinarily deployed for example in debates about freewill and moral responsibility.
And as Determinism is typically understood in these contexts it’s the thesis that the laws of nature together with the facts about the world at some distant point in the past circumscribe a unique future. So given the laws in the past there’s only one way for the future to unfold. We can formalize this just a bit and take the thesis to be this SD or Standard Determinism and it says this, “the world is governed by “or is under the sway of standard Determinism if “and only if given a specified way things “are at a time the way things go thereafter “is fixed as a matter of natural law.”
So Determinism got up with, you’ve got a description of the way the world is at a certain time natural law determines everything that goes forward after that. So is this the thesis of Determinism that Swinburne has in mind in his title? I’m not sure maybe though Standard Determinism comes preloaded with philosophical import the history of the freewill debate has conferred upon it, it does seem that Swinburne may have something less general in mind. So maybe the thesis Swinburne’s after is this call it Psychophysical Determinism PD.
The world is governed by or is under the sway of Psychophysical Determinism if and only if given a specified way things are at a time with respect to the brain states of some subject S. What mental states S will be in and what actions S will perform thereafter are fixed as a matter of natural law. So I’ve now put before us two Deterministic thesis one that is recognized as a general philosophical significance and another presented as my best effort to crystallize what Swinburne may actually have in mind.
And what I’ll try to show now is that Swinburne’s conclusion won’t do much to threaten either of these thesis. So would it show for example would the argument we’ve seen today would it show that standard Determinism is false? There I think pretty clearly not and Professor Swinburne seems to have admitted that at a couple points in the talk. The in principle predictability of the future entailed by Standard Determinism is perfectly compatible for example with any number of contingent obstacles to our succeeding in the project of prediction.
In other words Standard Determinism can be true even if Swinburne is right that we will probably never be justified in believing in our predictive power. In fact Standard Determinism can be true even if we establish that we will never be able to make the predictions. After all and again our inability to make the predictions may be explained not by the in principle unpredictability of the future including human behavior but rather by contingent limitations on our cognitive position and powers.
So to see this notice that for all Swinburne has argued here God might very well be able to make the predictions that we cannot on the basis of full knowledge of the past and the laws of nature. So that’s showing that we can’t make the predictions as Swinburne has argued isn’t sufficient to establish the falsity of Standard Determinism. And roughly the same kind of argument can be made with respect to the failure of Swinburne’s argument to show that PD is false. The Psychophysical Determinism is false.
It just doesn’t follow from our predictive incapacities that Psychophysical Determinism does not obtain. And again I take it that Swinburne admitted as much. But even if Swinburne’s argument can’t show us that Standard Determinism or Psychophysical Determinism are false, can’t it show us that we’re not epistemically justified in accepting them? I think not the best Swinburne’s argument can do I think is to establish that no theory like Standard Determinism or Psychophysical Determinism could be well justified on scientific grounds.
It’s those pesky criteria for scientific justification that are going unmet according to Swinburne. But whether belief in Standard Determinism or Psychophysical Determinism is broadly epistemically justified is another matter. I mean unless you think that a theory can be epistemically justified only if it is scientifically justified but you shouldn’t think that and I’m almost certain that Professor Swinburne doesn’t think this but just in case some of you are tempted to think that keep in mind that some theories just don’t fall within the domain of the sciences in such a way as to be getting their epistemic justification from scientific justification.
For example our failure to find scientific justification for say a udymanistic moral theory surely doesn’t license the conclusion that the theory is epistemically unjustified. The epistemic justification for a moral theory just may have nothing or very little to do with science. But even when theories fall within the domain of the sciences it is nevertheless false that our epistemic justification for accepting them need be principally a matter of the theory’s purely scientific credibility.
So long before Big Bang cosmology added scientific credence to the claim that the universe had a beginning in time. There were various philosophical arguments to the same conclusion. I can’t see any reason to think that people aware of these arguments couldn’t be epistemically justified in believing that the universe has not always existed. Even in ignorance of the cosmological evidence that we now have. Similarly astute observers of human behavior probably didn’t need the rigorous results of contemporary social psychology to be justified in believing that we are subject to the phenomenon of confirmation bias.
So I don’t see how an argument demonstrating that a theory could never be scientifically well justified would all by itself constitute a case against the epistemic credibility of the theory. Theory is premised on deterministic thesis like Standard Determinism and Psychophysical Determinism may be able to get their epistemic justification from something other than their scientific enos. So thus I don’t see, that’s you can use that. So what I don’t see then is how Swinburne’s argument could show us that belief in Standard Determinism or Psychophysical Determinism is epistemically unjustified even if it succeeds in showing us that no such theory could get the scientific stamp of approval.
So to be clear I accept neither Standard Determinism nor Psychophysical Determinism indeed I reject them both and I hold out some glimmer of hope that I’m epistemically justified in doing so. But I suspect that my rejection of them can’t get much of what whatever epistemic justification it has from Swinburne’s argument. Now maybe that Swinburne had something other than Standard Determinism or Psychophysical Determinism in mind when he gave his paper it’s provocative title or titles maybe other people forced those titles on you I don’t know.
But if so then I would be happy to hear what this thesis was, how the conclusion he takes himself to establish is related to it and why we should care about it. That is I’m happy to learn more about timekeeping and watchmaking from a truly masterful craftsmen. Thank you. [congregation claps]