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The Table Video

Richard Swinburne

Implausibility of Physical Determinism Q&A

Emeritus Nolloth
 Professor of the Philosophy of the Christian Religion, University of 
September 6, 2012

Visiting Scholar Richard Swinburne answers questions about his lecture, “Implausibility of Physical Determinism.”


Man: Just seems to me that the process of forming the intention is separate here from what actually fires the physical event. Okay, you make an intention to do something at some point after some kind of indefinite period. There has to be some kind of process going on here that essentially times that period.

Ah yes, sure. I mean, there’s clearly the intention. One makes the intention to do something tomorrow or something like that. But once again, if some scientist turns up and says that doesn’t make any difference to what we do, well, we have to do some experiments on this. And the experiments will have to say, will have to depend on information about when the intention was formed and what its content was. And the only way to find that out is from what the subjects tell us. And if the subjects, if what comes out of the subject’s mouth is not caused by their beliefs and intentions, then we should have no grounds for relying on it. So, the same point arises.

Man: Hi, Dr. Swinburne. My question is more along the lines of how do you, do you think it’s possible to believe that pure physical events could ever have some kind of intention? So, there’s like, something in the brain that lies dormant until a scientist sees a particular equation, and then that suddenly activated kind of like a dormant gene or something like that, which leads to kind of another physical event and another physical event which kind of leads to, I don’t know, like, discovering that epiphenomenalism or physical determinism is true. So, essentially my question is what do you think the chances are of getting intention or at least maybe some imitation of a mental event through purely physical processes?

Some indication of when someone is, yes. Well, that’s within the scope of what I said in my last paragraph that I wasn’t going to talk about. That is to say, whether our brain events sometimes or always cause our mental events. I don’t think they do, but clearly they do. I don’t think it always happens, but clearly it happens pretty often. I mean, the only reason you feel anything when somebody sticks a needle into you is because this causes something in your brain which causes a mental event. So, clearly this is a pretty frequent occurrence. And let’s be grateful that it is because if it were the case that you just formed your beliefs as a matter of choice quite independent of how things were in the world, you would soon come to grief. It is because of the fortunate fact that you form a belief that there is an item of furniture in front of you because the item of furniture causes light to come on your eyes, which causes the brain event, which causes you to have that belief. If there weren’t this causal process of forming your beliefs in the light of, no, not merely in the light of, but as a result of impulses to your sense organs, which cause brain events, then we’d be in a bad way. So, in general, of course it’s good that our brain events cause our mental events. But the issue is whether sometimes we form intentions, decisions about what to do with our lives which is not caused by a brain event. I think sometimes it’s not caused by brain events but that, and I apologize for that one Canadian lecture on one topic in one lecture, but that I’m not covering in this lecture. I’m covering this because so much popular science has drawn attention to this sort of result.

Man: Dr. Swinburne, I was curious if one could take the tact of trying to disprove or in some way hurt the theory, shall we say, of physical determinism by showing that we have intentions that we might not be able to act upon. For instance, if I have the inability to move my legs, but I have the mental intention to move my legs, could we point out that well, there seems to be mental events that happen which I’m not able to act upon where I intend things that are separate from physical things I’m able to do.

I’m not certain how you think that that is relevant. Sure, sometimes, sometimes our intentions don’t affect bodily movements. No doubt about that. But as regards fairly ordinary sort of things, pretty often they do, at least so it seems to us. Of course, sometimes they don’t. That is true, but I’m not certain how that would affect the general line of argument here.

Man: It’s just that if there was another way to go about disproving physical determinism by saying here we seem to have mental intentions that don’t accompany physical events, so the mental intentions might be prior and separate from physical events.

Well, it would cut, if it cuts at all, the other way. That is to say, an epiphenomenalist could say there are occasions when our intentions don’t make any difference. And we must surely admit there are such occasions, but this is not what we’re concerned with. What we’re concerned with is whether in general they do make a difference. So, I don’t think that would be importantly relevant I’m afraid, yes.

Man: Hi, Dr. Swinburne. Thank you for your stimulating lecture. I wanted to ask about, you said there about this order of sequences in Libet’s experiments that there’s this readiness potential, some spike in electrical activity or something that’s measured. Then an intention is measured. And then there’s the action, and you said oh well, great. It’s well and good in the order that there’s the intention and that we have the action, and that doesn’t show. But I wonder if you would comment about the readiness potential a little more. Like, do you think that that’s kind of like, the brain getting things going for us, and then we?


Man: What would you say about that?

Yes, well, I’m not a [laughs] neuroscientist, and there’s been a lot of detailed work on this. The answer to that is that it’s not clear what the answer to that is. But yes, there has been, Neuroscientists are good neuroscientists, but sometimes, they’re not really up to certain philosophical distinctions, and there are philosophical distinctions between, on the one hand a desire to do something, an urge to do something, and then on the other hand, the formation of an intention to do that something. That is to say, a decision to do that something. And when these experiments were first done, Libet and those who followed it just casually exchanged these words and some to some subjects report when you form the intention and to other subjects said report when you formed a desire to do that. And therefore, it just wasn’t clear what was being established. So, it is an issue. My view is that, what most, what most of the, Who knows what most of the subjects understood by the instructions that were given to them. So, it’s not clear what they are reporting here, but, the issue is really what in fact was going on when they were reporting something. I think that sometimes what was going on was certainly the formation simply of a desire in the sense when they form the, they had some sort of feeling that they were, that would be a good thing to do. And then only later did they decide to do it. But sometimes it may be they were reporting the actual decision to do it, who knows. I just don’t think we know what was happening in many cases. These things are being refined a bit now, and things are becoming clearer. But, as I say, my argument is designed to show whatever they meant by it, it’s not gonna make any difference.

Man: Yes, I had a question about one way to resist your argument. Can you hear me? So, scientists often rely on instruments.

Sorry, I can’t hear quite.

Man: Okay, can you hear now?

Yeah, much better.

Man: So when scientists rely on instruments, I would think that the evidence they get is a lot like, well, a lot like this. So, they’ve got some inductive evidence that says that an instrument is reliable, that there’s some process there that yields outputs that usually get it right. So, I was wondering whether a scientist, a Libet sort of scientist could just treat the testifiers reporting on their mental events as just like instruments almost. So, just get some inductive evidence that usually utterances that come out of their mouths get it right and then rely on that inductive evidence. And maybe do the same thing for the memory sort of case that you mentioned. So, we don’t have to attribute intentions to people. We just treat the outputs, what they’re saying as being reliable, there being reliable processes much like an instrument is often reliable.

Well [laughs], you say we don’t have to attribute intentions to people. The whole point of these experiments was to show that on the assumption they do have intentions, that those intentions affect what they do. So, as it were, the whole experimental apparatus was built up on the assumption that people do have intentions, and they are reliable in their reports on that. Now, I think what you had in mind is one might find out that somebody was a good reporter because they correctly reported various physical public events and so on. And therefore you might say well, because they reported physical public events correctly, they were therefore to be relied on in their statement about mental events. But you can explain why they reported their physical events correctly without assuming that there’s any downward causation from mental events to physical events because they could report their physical events, public events correctly in virtue of them having their eyes open, looking in a certain direction, our eyes from the event reported, The light from the event reported landed on their eyes producing a brain event, which itself led to them uttering the words I saw him on the campus yesterday. Now, that whole process could occur without them having any mental life at all. They could actually be robots. But they couldn’t possibly, [laughs] What we are doing is investigating their mental life. And so, some other process has to go on other than simply going on in the brain if we are to trust their reports on their mental life. And, of course, we do trust their reports on their mental life, but my point is we assume they have more. That other process going on is also a causal process just like the causal process when they report physical events. That’s the assumption we make. And that’s the assumption which the epiphenomenalist neuroscientists wishes to deny. So, you are saying yes, we can establish they’re reliable. Yes, I agree, we can establish they’re reliable, and that means that we are making the assumption. And for them to reliable, that assumption must be true. There is that downward causation.

Man: Hi, Dr. Swinburne. It’s me again. I was thinking about your lecture, and I noticed that you can have, intentions about your intentions. So, I can have an intention to, like to want chocolate cake or something, but then have the intention that I wish I didn’t have the intention, and, therefore, to resist that intention. And so my question is, to use your diagram there, it seems like that second intention is moving farther and farther away from the kind of brute physical processes or the brain events. And my question is is how would a physical determinist kind of explain that second intention away, or do you know of any good responses to that recognition of intentions to intentions?

I’m not quite with you on this. We can certainly, There are two sorts of intentions. There’s the intention in what we are doing. My intention in coming to Los Angeles, in getting on the airplane was, Sorry, my intention in going to the airport was to get on the plane. It was the intention in what I was doing there and then. But we can also form intentions for what we’re gonna do next week, yes? And therefore there are these two sorts of intention, the intention in action and the intention for the future. Now, I was only concerned with intentions in action. But the same kind of point can be made with the intentions for the future. The difference is, of course, intentions for the future sometimes just don’t, get forgotten or don’t affect behavior in any way. Whereas if we are right in supposing that we have an intention in what we are doing, being right consists in the intention affecting what we are doing. Whereas one can have honestly report an intention for the future, which makes no difference in fact. But nevertheless, if it does make a difference, the intention for the future, and if the scientist wants to say that, or rather it appears to, and the neuroscientist wants to say that it doesn’t, then, of course, you have to know when it occurs. And once again, the same problems arises, that he has to assume a downward causation from the mental to the physical in order to have that evidence. So, the same kind of problem arises in that case.



Woman: My question’s about psychophysical determinism. The answer to this may be quite long, so feel free to punt if that’s true. I have a question about something that’s on your notes, actually. You say here that to show psychophysical determinism scientists would need to establish a psychophysical theory explaining which brain events cause which mental events. And from what I know about functionalism, they’d want to resist that claim. They’d want to say there’s no need for some kind of straightforward correlation between brain events and mental events. We can make sense of that using internal, sorry, using other sorts of physical events, how those external physical events impact brain events. And we can tell that entire story without any kind of specific correlation story between brain events and mental events. So maybe you can say more about how you think a functionalist would–

Sorry, I’m afraid, it’s either my hearing, or it’s the mic or something like that. I didn’t quite catch the point, and I wonder if maybe it’s, Could you repeat it fairly concisely and slowly, please?



Woman: So, maybe you could say more about how a functionalist might respond to what you’ve written on your notes as a sort of response to the possibility of psychophysical determinism.

Oh, yes, yes, now you mentioned. I’d forgotten I’d added this paragraph. Yes, thank you, all right. We’ll move on to that paragraph. Yes, apologies for that. I’d forgotten that was on the paragraph, and I had originally intended to say a few words about that, and that’s why I put it on the paragraph. But then I decided that time was moving on, and I wouldn’t do that. Yes, well, once again, it’s a problem of how you would establish the psychophysical theory. Now, the way you establish any ordinary physical theory, Physics deals with only a few sort of quantities, the mass of an object, the position of an object, the velocity of the object. And when you do more sophisticated theories, a few other things like its electric charge, its spin, its color charge, and so on, you operate with only a few, who knows, 10, 20 sort of quantities of things and show how variation in one or two or three of these quantities meets a variation in a few others. And you form, and you can do this because you’re only dealing with a few sorts of quantities, and they’re measurable quantities. You can measure the mass of things, and then one thing can measure 10 kilograms. Another will measure 20 kilograms and so on. And you can form an equation between, for example, the momentum, the mass times velocity of one billiard ball and the momentum of another billiard ball, mass times velocity. And you can show that when they collide, momentum is always conserved. That is to say, the sum of the momentum of the first plus the momentum of the second before collision is going to equal that sum after collision. It’s because of this, which of course, one can make it in a bit more sophisticated form when one’s dealing with more sophisticated physical theories, but the point remains. The success of physics depends on being able to measure a few quantities and to establish a numerical relation between these quantities. Okay. Now, if you were to try and produce a psychophysical theory, a theory which related intentions, beliefs, thoughts, sensations, and so on to goings-on in the brain, you now have a problem, enormous problem. First [laughs], you are dealing with brain things, which are physical things, which are measurable things, and once again concern only a few quantities. But the things at the other end, the mental things, they are such different sorts of things which are not functions of each other. You can have all the different beliefs that a language might contain, and these are expressed in terms of concepts, some of which are interdefinable, but most of which aren’t. I mean, if you look at an ordinary dictionary of an English language, some of the terms are simply defined in terms of others of them. But most of the terms you learn you couldn’t understand from a dictionary alone what they mean. You would have to see things. You can’t understand what color or inflation or anything is without being exposed to these things and mere dictionary wouldn’t be enable you to define it. So already, simply with respect to beliefs, you are dealing not just with mass, velocity, and half a dozen other things. You are dealing with millions of different things which are interrelated. And they are not measurable things. My belief that today is Thursday, and there are a lot of people in this room, the one belief doesn’t have more of some quantity than the other belief or less, let alone a measurable more or a measurable less than this quantity. And so, the things, Just taking beliefs, the things at the mental end are just innumerable different things which don’t have any relation to each other except in some cases, but generally they don’t. And they’re not measurable. And the same applies to thoughts, let’s say occurrent thoughts and desires and intentions, and above all, sensations. One’s feelings, auditory sounds, patterns of color, individual field, and so on. All these things are different. They’re not interdefinable. They’re not measurable. Now what that means is if you were to try and show the relation between these, you wouldn’t merely have to have a theory with half a dozen laws. You would have to have a theory with billions of laws of the effect that if the brain was in such-and-such a state, then there would be such-and-such a mental thing. Now you might say, well, still we could, as it were, produce a variance to saying that if a certain part of the brain was in this state, then I would have a belief that concerns Thursday. And if a certain part of the brain was in that state, then I would have a belief about this room and so on. So there would be perhaps some sort of relation between bits of that and bits of that. But even that is not going to be possible because, mental events are, their very nature is, if we’re just concerned with beliefs, for example, is to be interconnected. You can’t have a belief, for example, that this is a lectern on its own. If I have a belief that this is a lectern, I have to have a belief about what a lectern is, that it’s used for putting things on when people giving lectures. If I’m to have a belief that something is a room, I’ve got to have a belief about what the room is and so on. So, beliefs, that is to say, come in packages. They can’t come as individual bits. And so, the most that such theory would, or what theorists would need to do was to show that some whole brain state was connected with some whole mental state. That wouldn’t tell you that if a bit of that was changed, a bit of that would change because if a bit of that would change, quite a lot of that might change. And so, the general point I would try and make, and thank you for forcing me to say what I said on the handout, is that if you, to establish such a theory, you would have to establish billions of laws on the basis of your study of lots and lots of brains. But here again, you’re gonna be in trouble because everybody’s brain’s different from everybody else’s, not merely in that they’ve had different experiences, but that the neurons are connected in different ways in everybody’s brain. And so, any evidence of what happens in one person’s brain is not going to be very good evidence of what happens another person’s brain, let alone what mental life is connected with it. So, how are you going to have repeatable experiments? The way to establish the momentum law is to do a large number of experiments, each of which would be evidence for it. But if you’re to have this billions laws connecting these things, you would need evidence for each of these laws. And the chances of having more than one piece of evidence for a given law is gonna be pretty small because nobody ever has the same brain state as anybody else ever. And nobody has the same conscious state, at any rate, when they’re considering serious moral issues as anybody else. Now that may be a bit of an exaggeration, but it’s not very much of an exaggeration. We all have such different views on particular issues which are tinged by particular past experiences and so on that our conscious life has qualities to it that other people’s don’t. And our life at one time is never the same as our life at the other time. And what goes for that for the mental goes for brains, too. And so you’re never going to have. Now, this is not, This is not a logically compelling view. It’s only a probabilistic view, but it is very probable that it would not be possible for any scientist ever to have enough evidence to support a general theory of this kind because you would need to have repeatable evidence for each component of this billion, billion set of laws. And you’re never going to have repeatable evidence for that because you’re never going to get anybody’s brain in the same state, let alone their conscious life in the same state, to be able to check out one of those laws. And that’s why I think you could never establish a theory of psychophysical determinism. And if that’s the case, well, we ought to believe that things are as they seem to be in the absence of counterevidence. And the way they seem to be, when we’re making serious moral decisions, not when we’re just walking around, is that it’s up to us what we do. And, it’s reasonable to believe that in the absence of counterevidence, if I’m right, there won’t be any counterevidence. So, that is the general point.