Curt Ducasse, "In Defense of Dualism" in Dimensions of Mind, ed. Sidney Hook, Collier Books, 1961, p. 88:
. . . the objection that we cannot understand how a psychical event can cause a physical one (or vice versa) has no basis other than blindness to the fact that the "how" of causation is capable at all of being either mysterious or understood only in cases of remote causation, never in cases of proximate causation. For the questions as to the "how" of causation of a given event by a given other event never has any other sense than through what intermediary causal steps does the one cause the other. Hence, to ask it in the case of proximate causation is to be guilty of what Professor Ryle has called a "category mistake" -- a mistake of which he is himself guilty when he alleges that the "how" of psycho-physical causation would be mysterious.
Is this a good argument?
Related Posts (on one page):
- How is it Possible? On Objections from Unintelligibility
- Dualism: The Traditional Objection and the Pairing Objection
- Ducasse on the Nature and Observability of the Causal Relation
- Ducasse on Mental-Physical Causation
- A Ducasse Ditty
- From the Mail: Interactionist Dualism
- Elliot Sober on Mind-Body Interaction
But does not the question "How does the one ball cause the other to move?" seem to be answered by pointing out that the one ball pushes the other? Yet there is no introduction of an intermediary causal step here.
I think Ducasse's point is well-taken. Our causal explanations are always remote in the sense that our intellect does not penetrate to the ground of being (only God's does that), and therefore our explanations always leave something more that is unexplained. It is always possible to point to the remaining mystery in an explanation and say that, since the explanation doesn't explain everything, it explains nothing.
But our causal explanations, although they do not finally penetrate to the ground of being, are real explanations because they illuminate the phenomenon in question. They take some of the mystery out, but not all of it. Explaining that one ball moves another by pushing is not an empty explanation, and neither is the explanation that my fingers move because my soul wills it.
None of this is to say that a final account of the properties of the physical world will not ultimately rest on brute facts. But it is wrong to suggest that our current understanding of physical causation is on equal footing with the non-explanations given for these alleged "mental-physical" interactions, for which no model whatsoever is proposed, even at the most superficial level.
One point to bear in mind concerning Ducasse's theory is that he holds the relata of the causal relation to be changes or events and not substances (particulars.) Thus a ball cannot enter into a causal relation. One ball does not cause another to move by pushing it. It is rather ball A's hitting ball B that causes ball B's moving.
What Ducasse is getting at is that in a case of direct ("proximate") causation, there is no 'mechanism.' (Compare the starting of a car engine which involves a series of intermediate cause-effect relations.) Let C and K be changes or events. C causes K just in case C occurs in the immediate environment of K; C occurs immediately before K; C is the only event that satisfies these two conditions.
Ducasse's is a singularist analysis as opposed to a subsumptionist or nomological analysis. Events are not causally related in virtue of their instantiation of a law-like regularity; laws and regularities are generalizations from singular cases of causation.
Of course, what constitutes "hitting" is a concept that is not so simple; the closer we look, the more we see. Can this be said of mental-physical interactions?
Ducasse seems to be arguing that mental-physical (MP)causality is as opaque as "proximate" physical-physical (PP) causality, but they seem in fact to be quite different, as we are able to "drill down" into the PP relationship in a way that we can't in the other case.
If laws and regularities are only generalizations from single instances of causation, as opposed to instantiations of underlying laws, are we then to be comfortable without feeling the need to ask why such generalizations, which often have perfect predictive power, are possible?
Are dualists proposing that continuing physiological studies will find a "dead end" of some sort where the ordinary causal chain of connected neural signals suddenly leaps into action without an obvious physical cause? That in itself would be a useful empirical prediction that dualists could make, and would bring the problem into the purview of experimental science.
I'm not sure whether physiological studies will ever come to a dead end in hunting down material causes. I rather think they won't. But I am sure that physiologists will never understand in purely material terms phenomenon of the form:
1. I choose to raise my finger.
2. My finger rises.
I don't see how the epiphenomenalist case has advanced much since the time of Plato. Why does Socrates sit in prison? Is it because his muscles are connected to his bones, and one muscle contracted and then another, carrying him into prison? Or is it because the Athenians thought it just to condemn Socrates, and Socrates thought it just to submit to the sentence? The former explanation is one in terms of physical causation, the latter an explanation in terms of intellect and will. It seems clear that the "horse" in this situation is the explanation in terms of will and justice, the "cart" the movement of bones and muscles. I submit that the firing of neurons is as much in the cart as are the bones and muscles.
Of course we have advanced quite a bit since the ancient Greeks in our understanding of physical causation. But does couching the explanation in terms of neurons and brain chemistry instead of muscles and bones really change anything? The neurologist can go beyond the bones and muscles to the neural activity that causes it, but he doesn't seem any closer to discovering justice or Socrates reasons for sitting in prison by doing so.
To answer your initial question, I think Ducasse's diagnosis is correct and that it would be salutary if more people thought that clearly.
I'm intrigued by Malcolm's position, which seems, as he's presented it, to be a matter of unargued dogmatic determination never to accept dualism. I don't doubt his sincerity; indeed, I suspect that he's simply being more honest with us than some of the critics of dualism. (I recall a remark Mark Rowlands once made in conversation that the real root of his objection to dualism was not any argument but rather physicalist bias. There, too, the candor was refreshing.)
I'd say that what your are zeroing in on is more an issue of what reductive or hierarchical level we ought to be looking at than a physicalist/dualist issue. Yes, Socrates' muscles and bones carried him to prison, but rather than detailing the individual nerve-cell activations it is more helpful to say that "he walked". Nevertheless, if one wished one might describe the whole operation in tedious detail at the neural (or below that, the molecular) level. Different hierarchical levels offer different explanatory conveniences. Likewise it is not helpful to describe the trial of Socrates at the molecular level, but the same is true of, say, forest ecology, and no one seems to be insisting that a dualist account is needed there.
My point about the "dead end" is being missed here, I think, so I'll try to give a clearer example of what I am talking about.
Imagine an experiment in which the subject is asked to point at a dot of light when it appears on the screen. The dot appears. The subject moves his finger. Now at the current state of neurological understanding, we can follow the causal chain from both ends - from one end, we have the photons entering the eye, the retinal excitation, the stimulation of the optic nerve, and the activation of certain areas of the visual cortex (there may be more that is well known, but this will do for this example). On the other end we have the muscular contraction that moves the finger, which in turn was preceded by a chain of motor-neuron signals, which was preceded by activation of the supplementary motor area of the brain, and so forth. It is what lies in between these two quite ordinary physical processes that we seem to be disputing. At present the linkage is still something of a "black box", but physicalists assume that this is simply a matter of our ignorance, and that the area enclosed by the box will eventually shrink to nothing, leaving us with a completely connected causal chain. The dualist account seems to be that inside the black box there is a transduction from the physical to the mental, some decision-making in the mental domain, and then a retransduction from the mental back to the physical, resulting in "output" from the box in the form of the neural signals that will move the finger. What I was saying about a "dead end" is that if dualism is true, and we are assiduous enough in following the causal chain of neural activity (which seems, given the rapid progress in neurological tools, not unimaginable) we might actually come to the place where this linkage between the mental and the physical happens, which would look like a causal "dead end" of sorts.
Good description. It's logically possible, but I don't think we'll ever get there -- the progress in neuroscience doesn't seem to me to be of the sort that will take us down to that level. (I'm trying to imagine spreading a brain out across acres of sterile porcelean and then loading it with nano-scale sensors ... nope, not gonna work.) So we'll have to live in the zone where we don't have that kind of information.
Actually, I am NOT determined never to accept dualism; believe it or not, I consider myself quite agnostic on the issue (much more so than I used to be, thanks to the strong defense of dualism I have seen here at Bill's excellent salon). I freely admit that I do have intuitions that pull me strongly toward physicalism (just as many here have intuitions that pull in the other direction), and as I mentioned before, dualism seems to me to be a sort of a cop-out, a "God-of-the-Gaps" explanation that in my opinion is a rather desperate, vacuum-abhorring try at having some account, no matter how magical, of subjective consciousness. But for all I know, it may indeed be true. I'll admit, though, to take Nagel out of context, that "I don't want the universe to be like that."
All I am attempting is to be a vigorous devil's advocate, and to try to make sure that serious physicalist models and objections are well represented in these discussions, which I think, frankly (with apologies all round), they otherwise would not be.
One thing I have learned to be skeptical of is assertions about what scientists will never be able to do.
They used to say the same thing about heavier-than-air flight.
I've been arguing my head off in here!
I think your experiment with the dot of light still makes the mistake pointed out by Socrates. It fails to distinguish between the real cause and that without which the cause could not be a cause. The real cause of my finger pointing at the dot is my formal decision to cooperate with the scientist in his experiment. That decision is an act of my will and formally superintends the entire experiment. At any point during the experiment, I could decide to stop cooperating and point my finger somewhere else.
Now, I agree that given the formal act of the will to cooperate with the scientist, the experiment can be adequately characterized in purely physical terms. Just as, given Socrates formal decision to act according to his understanding of justice and submit to the sentence of the Athenians, his trip to jail can be adequately explained in a causal chain of bone acting on muscle. What I dispute is that further research into neurons or bones and muscle will ever shed light on the formal decision of the subject to cooperate with the scientist or Socrates to submit to justice.
One reason I doubt it is that scientists deliberately exclude the phenomenon of rational will from scientific study. In the experiment you suggest, for example, if I choose to stop cooperating with the scientist he will not view this as a fascinating phenomenon that challenges his understanding of human nature. Instead he will fire me and find a more cooperative subject. Notice that scientists never need to ask photons, chemicals, rats, pigeons or dogs to cooperate in order to make science work. But men must be so asked, and it is because we have a rational will that transcends the scientific method itself and will never be explained by that method.
Another reason I do not believe science can ever fully account for man's intellect and will is the following. If such an accounting is possible, then it must account not only for the subject in the eye experiment, but also the scientist conducting the experiment. Who will give this account of the scientist? Perhaps another scientist through a scientific investigation of the first scientist's behavior? That may account for the first scientist, but the very act of understanding the first scientist creates a new scientific understanding in the second that needs to be accounted for. A third scientist will be necessary, etc., etc., in a never-ending chain. This is a consequence of the fact that our intellect and will transcend science by the very act of understanding, and therefore can never be understood by that science. Scientists implicitly concede this point by deliberately excluding the will from scientific investigation in the manner I pointed out above.
With regards to rash predictions about the inability of scientists to perform things like heavier-than-air flight. I'm willing to make a bold prediction about something scientists will never be able to do:
A scientist will never be able to completely understand the behavior of scientists through science.
We should also strive to avoid the conflation of epistemic and metaphysical issues -- our inability to articulate complete causal stories isn't particularly relevant to the question of what causal relations obtain.
The physicalist response to your remarks would be that you are mistaking our ignorance of the complete physical system - an epistemic, or perhaps merely technical, difficulty - for an unwarranted ontological distinction.
As you point out, the experimental subject must agree to participate in the procedure; but how do you know that in so doing he is not simply entering a complex physiological state that will moderate the "black box" output in the appropriate way? Certainly a sophisticated computing device could be arranged to be in such a state (not that I am arguing for a purely "computational" model of the brain).
"Well then," you might argue, seeking a regress, "what caused him to decide to enter such a state?" The answer would be, quite simply, his previous dispositional state (and the environmental context, including a psychologist asking him to do so). I see here no serious objection to the idea that we are born with a "factory preset" neurophysiological setup, upon which the impressions and experiences of life impinge, resulting in our complex, unique, and ever-changing dispositions.
While I agree that it is easier, in some ways, to work with rats and pigeons, even they must in fact be trained. Photons, being somewhat simpler than human brains, require less preparation.
You wrote:I think you are multiplying the need for "accounts" beyond what is called for. First of all, it is not necessary to examine, say, every axolotl to understand the basics of how axolotls work, but more importantly, if we can arrive at an account of the dispositional state of the first person in the chain, we can simply take any external signals (i.e. those coming from the next scientist) as input, without the need to analyze their source, and so forth. If we are able to arrive at a satisfactory physicalist account of one person's behavior, I think we might justifiably argue that the same principles apply in others.Without wishing to be rude, I must say that the first part of this statement strikes me not as an argument so much as what Tim, above, called "dogmatic determination". As for what "scientists" concede: given that the overwhelming majority of scientists doing this sort of work are not dualists, it is likely that they are merely making concessions to what a physicalist would see as a temporary state of ignorance. In scientific experiments it is necessary to constrain the number of variables as carefully as possible; a noncooperative subject is simply undesirable for the job at hand.
You ask: "But what does 'pushing' mean? Why should one ball start moving when struck by another?" You then add: "My point is that there is indeed an intermediate causal step involved in 'pushing'. It is the causal step that answers the question why a ball moves when hit by another rather than just staying still."
There is confusion here. The question "Why does B move when hit by A rather than just remaining still?" is a fine one, and it has an answer, but that answer doesn't reveal any intermediate causal step between A's pushing on B and B's moving. I would answer with something along these lines: When A pushes on B, it makes a claim on a region of space occupied by B, indeed a stronger claim than B makes on that space, and no two things can occupy the same space at the same time, so B must move out of that space. This strikes me as a perfectly fine answer to your question, but it introduces no intermediate causal step. There is no tertium quid X here such that A has a causal influence on X and X in turn causes B to move. (Note: A's pushing on B doesn't cause it to make a claim on a region of space occupied by B; rather, A's pushing on B involves its making such a claim.)
So it seems that you have provided no real reason for thinking that there's an intermediate causal step here, and therefore that you haven't successfully defended Ducasse.
Auguste Comte once tried to give an example of what was beyond the bounds of scientific inquiry:
In 1862, five years after Comte died, Anders Ůgstrom discovered the presence of hydrogen in the sun, using the new techinque of stellar spectography.
(Proximate) physical-physical causation
Q1: How does the one ball (A) cause the other (B) to move?
A: A pushes B.
Q2: But how does A's pushing on B cause B to move?
A: In pushing on B, A makes a claim on a region of space occupied by B, indeed a stronger claim than B makes on that space, so B must move out of that space.
Q3: But how does A's making a stronger claim on that space than does B cause B to move?
A: No two things can occupy the same space at the same time, so the thing making the weaker claim for a given space must move out of that space.
Q4: But given the principle that no two things can occupy the same space at the same time, how does A's making a stronger claim on that space cause B to move?
A: I don't know what else to say; that is where the answers end.
(Proximate) mental-physical causation
Q1: How does the soul's willing cause some movement in my body, specifically in my brain?
A: I don't know what to say; that is where the answers end.
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I might be willing to agree with David that there is some degree of inexplicability in both cases, but is it not clear that there is much more intelligibility and explicability in the physical-physical case than in the mental-physical case? After all, in the former case we get to Q4, whereas in the latter we never get past Q1.
In the case of proximate physical-physical causation, I agree with David's analysis: "our causal explanations [are] real explanations because they illuminate the phenomenon in question. They take some of the mystery out, but not all of it." But in the case of proximate mental-physical causation, nothing could be further from the truth: nothing has been said to illuminate the phenomenon in question. It remains utterly inexplicable and unintelligible how the soul's willing causes anything to happen in the body.
Thanks - this agrees entirely with the point I made in this comment above, and, as I mentioned, you could in fact carry the questions in the PP case even further than you did in your example, while the alleged causal account in the MP case has precisely zero depth.
So far in my understanding of the point Bill has raised, I cannot see how Socrates' final decision to yield to the justice of Athens can be the proximate cause of anything beyond the firing of the very first neuron relevant to and immediately following the mental act. I seem to see here "wrapped up" causal chains being understood as the immediate results of mental acts, but somehow that seems to me to miss Ducasse's point. As soon as we begin to answer the question of how a physical change occurs in response to a mental change (or vice versa), we seem to have passed out of the realm of proximate causes.
The whole discussion recalls to my mind a theological one I have considered in the past. Calvinists may argue that salvation precedes faith, and I take that to mean that salvation is understood to be the proximate cause of faith. For those Calvinists, there is nothing between salvation and faith, yet salvation must precede faith. But how does salvation cause faith? If salvation is the proximate cause of faith, how can that question even be answered?
I take it that Ducasse's argument is similar, where a given mental event or change immediately precedes a given phyisical event or change in the same environment, or where a given physical event or change immediately precedes a given mental event or change in the same environment. In neither case is it possible (for me) to say how the thing works.
This seems to me also to apply to purely physical change. As I'm writing this I'm mashing at my keyboard (I cannot type) and letters appear on my screen. I can analyze the complex causal chain to sort out how it works from keyboard to screen, but it's not so clear to me how I might sort out the how of any given proximate cause along that chain.
Now, where have I gotten myself lost?
You wrote:
Not if the job at hand is to explain the rational will, which is the faculty of deciding to be cooperative or not! It is one thing to exclude an irrelevant variable, quite another to exclude the very thing that is supposed to be explained.
I know that most scientists are not dualists. Neither are they philosophers, and the philosopher can see what the scientist is assuming even if the scientist doesn't see it himself.
Surely the difference between asking a human subject to cooperate and training a rat is more than the fact that one is hard and the other easy. The rat's behavior does not rise to the level of cooperation or non-cooperation, because it has no way of rationally understanding what is going on. That's why it makes such a fit subject for scientific study. Can man, who can understand what is going on and take a stance with respect to it, be understood by the same method that understands the rat?
Physicalists do not seem interested in such questions. And of course, the physicalist can write a blank check on the future, say all will eventually be explained, and simply charge ahead with his investigations. I admire his energy and confidence, but not his tendency to bulldoze over the distinctions between men and animals.
I mean no disrespect with that last sentence. But my skepticism toward physicalist theories is partly driven by the fact that the more they are pressed, the more man seems to disappear rather than be explained. The rational faculties of intellect and will, so profoundly analyzed in Plato, Aristotle and Aquinas, are not so much explained as simply ignored. Were a scientist to announce a way to understand the rational faculty through a physical theory, I would listen with interest. When he announces that he has analyzed the neural pathways that make my finger rise when I choose to make it rise, and therefore has gotten closer to explaining the phenomenon of man, I suspect that he doesn't really understand as much about man as did Socrates.
Well, presumably when experimenters are actually investigating the rational will, they don't exclude it from scientific investigation, so I'm not clear exactly what sort of example you are offering.
First things first. In attempting to understand Man, we are confronted with an immensely complex physical system, and the job must be broken down into simple steps. We must get a good picture of what is happening in the brain before we can even begin to account for the observations of Socrates and Aquinas. The study of Man's nature can proceed from many directions at once, and the great philosophers have done a fine job so far. Now the neurophysiologists have begun as well, and work continues apace. Why declare defeat when the battle has only so recently been joined? Why not hope instead for the driving, someday, of the Golden Spike that links the two efforts? What, other than dogmatic assertions of Man's obvious superiority to the merely physical, can you offer as proof that such investigations are doomed? They may in fact be doomed, but how can you possibly know?
One point here is that in the case of ordinary physical causality it is possible to "drill down" a long way in understanding the causal process - from balls down to molecules, down to atoms, to electron shells, to messenger photons, etc. - and scientific investigation hasn't hit bottom yet. Of course, it may ultimately turn out that some irreducible bottom level corresponds to the truly "proximate" causality Ducasse refers to.
But when considering neural processes, it is hard to see why it is necessary to consider the causal chain at such a low reductive level - rather we can say neurons A, B, and C being in a "signaled" state cause neuron D to fire. At this level the "proximate" causal linkages between neurons are not mysterious, and it would be interesting to hear from the dualist camp just where the "mental-physical" version of causality is alleged to enter. Presumably at such a point we would see a neuron firing without the appropriate stimulation from its neighbors; this is what I meant when I suggested that dualist models could usefully predict a causal "dead end".
I'm glad you agree. (I thought you would.) You may be right about giving further explanations, but I think I succeeded in making my point without moving to the subatomic level.
Indeed you did. Just wanted to call attention to the confluence of our arguments.
Several things come to mind at this point, but here goes, briefly.
First, I'm seeing no reason to consider theoretical soul-body interaction as shallow relative to theoretical body-body interaction. If I were to posit a soul-body "interface" (borrowing some terms from computerdom for convenience), I'd have to begin by describing it as "parallel" rather than "serial," as "bidirectional" rather than "unidirectional," and as "full duplex" rather than "half duplex." I sense a good deal of depth and complexity in the model even at the outset, at least a good deal more than seems to be so far allowed here. Perhaps on further reflection I'd find that the depth my intuition finds at the outset isn't really there, but I have yet to be convinced that the model has nothing to say in answer even to the first "how" question.
Second, I cannot yet see how to resolve the mystery of proximate causes even in physical systems. In what way does the description of the event "neurons A, B, and C being in a 'signaled' state cause neuron D to fire" explain or remove the mystery of the how of a proximate cause in a physical system? If I'm following you right, you seem to see no need watch the causal interaction at that level to understand (or at least discuss) the overall process involved, and I follow that. But the issue at hand (as I understand it) is an objection to dualism and the assertion that it is an illusion that physicalism avoids the same objection. In that light looking at the notion of proximate causes seems necessary and on topic.
Well, if you will insist that we look at the lowest possible physical level, where the causal "rubber meets the road" (and that bottom has not been found yet by physicists), instead of at the already low level of individual neurons, you may be right, as I have agreed, that there is a brute and inexplicable causal reltaion even among purely physical events. What I suggested in that case was that this should have observable consequences at the neural level, because neurons in which mental-physical causation was occurring at the truly "proximate" level would activate without apparent stimulation in the ordinary way, by adjacent neurons. In this way dualism might become an empirical question.
Let's imagine what an experiment would look like that attempted to investigate the rational will of man as such, and not merely an experimentally constrained set of physical consequences of that will. It would have to go something like this:
1. The scientist tells the subject that he is attempting to characterize the free, rational will of the subject. The subject is to consider himself free to respond in whatever manner he may choose to the coming request of the scientist. The scientist has whatever neurological monitors he desires hooked up to the subject.
3. The scientist asks the subject to raise his finger.
Now, if it is true that the scientist has a real hope of eventually capturing the rational will in his physical theories, he should someday be able to predict what happens next based on his neurological monitoring of the subject. He should at least predict what happens next with some degree of probability. And what might happen next? Here is a short list:
1. The subject raises his finger.
2. The subject does nothing at all.
3. The subject gives the finger to the scientist.
4. The subject gets up and walks away.
5. The subject starts whistling "God Bless America."
6. The subject grabs the finger of the scientist and raises it instead of his own.
7. The subject sits there and ponders the philosophical possibility of characterizing the rational will through science.
8. The subject thinks of all the things he's done in previous trials in this experiment, and does something else.
9. The subject reveals that he has actually been investigating the scientist, and has been attempting to characterize the scientist's response to his responses.
etc., etc., etc.
The point is that the will, when not artificially constrained, is potentially infinite in its responses. Rats and pigeons aren't like that. Their behavior falls into certain definite limits. Put a rat in a maze with a piece of cheese, and one of a very few things will happen. That's why the scientist can finally capture the nature of a rat in his theories. But the nature of man is such that he is always breaking out, acting in new, unprecedented and creative ways. It is that characteristic, the final freedom of the will, that I think poses a stumbling block for the scientist.
The above is a reason for believing the scientist will never finally understand man through his physical theories the way he might understand a rat. Of course it is possible I am wrong. But until someone describes how, in principle, a scientist might come to understand the will in all its freedom, I think I am justified in dismissing such a claim as based on unfounded optimism.
Response #3 in the above may be the most interesting. If the scientist asks me to raise my finger, and I raise my middle finger to him, am I cooperating with him or not? This response seems different in kind, not merely degree, from whatever response a rat or pigeon might give in an experiment.
Suppose the scientist is from a foreign country and doesn't understand the significance of the middle finger. He thinks the experiment with subject A who raised his first finger is no different than the one with subject B who raised his middle finger. To him, they are just cases of "raising the finger." Is the scientist correct? Or is his scientific approach incapable of grasping the true reality of what happened in the experiment?
Just to be clear, I'm not prepared to insist on looking at proximate causes, nor am I certain that proximate causes must always be subatomic. My question really was/is a question, and it's about an objection to dualism and Ducasse's response, and then about the responses to both objection and response here.
Relative to your comment about neurons firing without an ordinary phyiscal cause, I wonder if that's what dualism entails.
You seem to take it as given that the will of Man (and this, apparently, in contrast to all other animals) is absolutely free, rather than being the output of an astronomically complex physical system, an output that is unpredictable only because we cannot yet see the complete causal web.
Do you see this as a position one can compellingly defend in the face of a physicalist's skepticism, or is it simply an axiom about which you and the physicalist must disagree?
I don't think that good physicalists "bulldoze over the distinctions between men and animals" - but then, dualists probably don't think they bulldoze over the similarities, either. Intuitions are hard things to shake off, I admit.
If I am understanding the passage from Ducasse correctly, he is suggesting that alleged MP causality shouldn't be considered any more mysterious than "proximate" PP causality, because we simply have no explanation for either.
My point is that for this objection to apply to a physicalist model of mental activity - which considers the units involved to be neurons - it would be necessary for neuron-neuron causality to be the level at which we reach "proximate" physical causality ("proximate" taken to mean without any intermediate causal steps). But in fact the communication between neurons is mediated by a great many underlying (and well-understood) causal interactions at lower physical levels. So I think Ducasse's objection might either simply be flawed, or might usefully predict (if dualism is true, and the MP causal interface is at the lowest, truly "proximate" level - wherever that is) that we would see otherwise unexplainable neural activation.
I'm not explaining my position very well, because I don't think it rests on intuition. I think it rests on empirically observed human behavior, and I've given examples that are as concrete as I can make them. The difference between a rat chasing a piece of cheese in an experiment and a human subject giving the finger to the scientist is that the latter has meaning and the former doesn't. The point of the 9 possible responses I give in my earlier post is that some of them carry meaning and others don't. I don't see how the scientist's method, which does not account for meaning and therefore works well on rats, will ever capture the meaning in human behavior. The freedom of our will is not a result of it being complex, but that it acts at the causal level of meaning. That isn't intuition, but fact. I see people acting meaningfully every day.
The attempt to understand man as a product of purely physical causes is like trying to understand Hamlet in terms of the physical processes that produced the paper and ink and printed it. The physicalist can hope that if he pursues his physical studies of paper and ink far enough, somehow he will come to a complete understanding of Hamlet. But we can see that his hope is false, because he is pursuing the wrong kind of explanation.
Surely there are similarities between men and animals, as there are similarites between men and logs. Now a physicalist can drop a man and a log from a tall building and see that they both accelerate at approximately 9.8 m/s^2 toward the ground. And he may justifiably say that he can account for the behavior of both the man and log through the theory of gravity. But he is not justified in concluding that, because he explained men and logs in a similar manner in this case, that men and logs can therefore be finally understood by the same method. Similarly, simply because men and animals can be explained by similar methods in some cases, it doesn't follow that they can be similarly explained in all cases. If we want to make that conclusion, we must account the empirical differences between men and animals, which is why I keep pointing them out.
I appreciate your patience here. As Bill has pointed out elsewhere, working people are disadvantaged when it comes to having the time necessary to a contemplative life. When it comes to deep thinking, at best I'm the tortoise and not the hare.
Suppose I have a computer that is operational but without a given task, that is, without a running application. At the "on/off" level of the computer, at the binary operations level, if we could watch, we'd see some activity while the computer "idles." Peripherals would be polled, the screen would be updated, and so on.
Now suppose I launch an application. Other than in frequency, in what way(s) might the computer's on/off states look different? How would I distinguish system-driven and application-driven on/off states just by observing the states themselves?
I might have a clue based on which parts of the CPU come alive. I might be able to say, "System events would not trigger this activity in the floating point unit, so an application must be running." But that kind of perception would only be as good as my understanding of the CPU's architecture. My sense is that at the binary operations level alone, I will have no certain knowledge of what causes any given on/off state or any given series of on/off states.
Is it possible that in a model of human mental-physical interactivity which has "parallel," "bidirectional," and "full duplex" characterisitics that I could predict that I would not be able to distinguish mental-physical and physical-physical activities within the brain at the neuronal level?
I don't dispute that that humans exhibit more flexible and sophisticated behavior than rats, and of course I'd agree that birds don't write tragedies. Nor do fish argue about dualism. I don't in any way deny that the human brain's astonishing complexity gives us talents that most, if not all, other animals do not possess.
But what I am saying is axiomatic in your view, and is, I think, an opinion based entirely on intuition, is the notion that simply because we perceive and act upon meanings, our sophisticated behavior cannot be the result of physical causes. As I have been arguing for months in this forum (and at my own website, for example in this post), there is a perfectly defensible physicalist account of how "meaning" enters the physical world as organisms evolve. Doesn't the dance of a bee, which informs the other bees about where to find food, convey meaning? Yes, the behavioral repertoire of a bee might not give it as many options for responses as we would have, but still it draws meaning from the dance, and makes a decision to go find the food, knowing now where it is (a decision that might go the other way depending on other impinging factors, such as a storm beginning, the hive being under attack, etc.).
There is a key difference between animals (such as humans) and logs, which is that animals are living, purposeful, intentional entities, and logs cannot be said to have "interests" (trees can, of course, but not logs).
Right. But nor does it follow that they can't.
It is important to keep in mind that the possibility that the activity involved in writing a play - or giving a scientist the finger - is reducible in principle to physical causes does not mean that the neural hierarchical level is a desirable one for its explication, any more than you would seek to explain the details of a hurricane in terms of individual air molecules. But that does not mean that the hurricane requires mysterious non-physical forms of causation for for its explication.
I am not trying to prove that a dualist account of the mind of man is necessarily false. All I am saying is that the physicalist model is a live option as well, that it is premature to declare the matter settled, and that the examples you give of Man's alleged freedom of will, and of the indisputable subtlety of his behavior, are not refutations of physicalism. Nor, I argue, is Ducasse's point about the bottom-level mystery of truly "proximate" causality applicable to the causal level at which neurochemical interactions proceed.
Presumably with a good enough knowledge of the computer's hardware architecture you would be able to understand why each bit in memory is flipped or not at each clock cycle. There would be "process spaces" where application data were allocated in memory, etc. that should all be traceable. Certainly we would not feel the need to assume any "dualist" causality was taking place.
The human system is obviously vastly more complex than any computer. While this makes the task of understanding its causal web enormously more challenging (and I have never denied that the problem might indeed turn out to be impractically large), what I had suggested was that in principle an objection such as Ducasse's might imply that any MP causal influences might be detectable, as they might result in neural activation that would be without any obvious physical cause.
Also complicating the task of analyzing the mental by watching the physical is that each brain, to a large extent, writes its own operating system, and even wires up its own hardware. We would certainly have to rely, much of the way, upon subjective reports from the brain itself that is under examination. It may very well be that the problem is simply too large, and will always be beyond our grasp. But that in itself is in no way evidence that the brain (and the mind that is one of its running "applications"), is anything more than a physical system. Again, I am in no way attempting to refute dualism here, though I suspect it is no more than an alluring and reassuring illusion. All I am attempting is to rebut the notion that anyone has mounted a successful refutation of a physicalist model.
I think I can see the difference between what you're trying to do and what you're not trying to do. I'm not trying to refute either, but to explore.
If Ducasse is right that there is no "how" explanation to proximate causes, and if the flow of neuronal activity (whatever causal staus that might have) alone is insufficient to settle causal questions, then at worst we're refining the nature of the exploration. Or so it seems to me at the moment.
The difference between bees and men is not that men have a few more behavioral responses than do bees. Were that the case, then I might agree that man could eventually be explained by a purely physical theory. What distinguishes man from all other creatures is the potentially infinite nature of his responses. I listed some responses a man might make to the "raise your finger" experiment, but I could go on with that list indefinitely. It is this peculiar quality to man's actions, that they do not seem bounded in the manner of other animals, that I think poses a problem for physicalist theories. I think this difference between the behavior of man and animals is just as significant as the difference between animals and logs.
One reason that man's actions are not bounded is that the meaning that man can know and act on is not limited. That's not my intuition, but empircal fact. I won't argue about whether bees truly communicate meaning, but I will argue that the meaning they are involved with is strictly limited if it is there at all. That's why science can get a handle on bees.
Maybe we can agree on this: If the nature of man's actions is infinite, then physicalist theories are doomed to failure, because there will always be responses of man that are not accounted for in the theory. In fact, any scientific theory at all would never be able to fully characterize man because there would always be actions of man that were not accounted for by it. (For example, the reaction of man when he comes to know such a theory as proven. How can a scientific theory account for a response that doesn't exist until the theory itself is finished?) Our argument would then turn on whether the actions of man really are infinite. I think it can be demonstrated that they are.
My problem with physicalist theories is that no one has ever explained how one might capture the infinite nature of man's behavior in a theory. As I see it, the physicalist must either show how that can be done or deny that man's responses are in fact unlimited. Either horn of this dilemma seems to me untenable.
I am inclined to agree that your assertion that man can assume an actually infinite number of states is indeed a key point here. You say that you think it can be demonstrated that this is so, and I would be interested to know how that might be done. My own inclination is to think that the physical system that creates the mind of man is of a complexity that makes it seem infinite, that the plasticity of its internal connections allows for a truly vast number of combinatorial possibilities, and that furthermore the hardware itself, being living tissue, is reconfigurable as well. So the number of states available over the course of an individual's lifetime is indeed going to be astronomically immense.
But what makes you so sure that the human repertoire is literally infinite? One might form such an argument by positing a recursive sort of mental content, such as "I think that he thinks that I think that...", and argue that such a concept could be extended ad infinitum, or one might make the case that the combinatorial flexibility of language makes possible an arbitrarily extensible set of representable concepts, but how do you know, as your position seems to imply, that any actual person is capable of instantiating it all, without limit? As there is obviously no way of proving this by example, I think you are relying here once again on intuition.
Furthermore, where is it shown that an immaterial, dualist mind must have an advantage in this regard? To the physicalist, if you are going to go right ahead anyway and simply declare that minds are immaterial things that somehow (!) interact with our bodies, I suppose you aren't stretching credulity any further by making the additional claim that they are infinite as well, but the whole thing has the whiff of fantasy, and we have scant reason to believe any of it.
The physicalist wonders: If mind is immaterial, why should tampering with the physical brain affect it? Why should damage to tiny areas of the brain, or slight adjustments in brain chemistry, cause radical personality changes? Why should stimulation of small groups of cells trigger particular, and repeatable, mental phenomena, such as sounds, smells, and memories?
An afterthought: even something as simple in comparison to the human brain as a digital computer can run a potentially infinite number of different applications, and exhibit an arbitrary number of different responses, as long as we are willing to extend, physically, the number of available memory states as needed. Certainly it is easy to imagine a program space so vast that it would appear infinite in any practical application.
Sorry to take up so much space, but there is one more point I feel I must address. You wrote:A physicalist account of mental phenomena should not have to issue a catalogue of every future state of every mind in order to be the correct view, any more than a physicalist account of the weather is invalid because it doesn't predict which trees will blow down in next summer's hurricanes. All I am arguing for here is the possibility that the reaction of the man upon coming to know that a physicalist theory of mind had been proven would itself be a purely physical event.
Take as much space as you like. I'm enjoying the discussion!
Here is an argument why the mind cannot be a purely physical thing like a digital computer:
1. Physical things are finite. A computer, or my brain, is not composed of an infinite number of cells or atoms.
2. Because they are finite, physical things are bounded. Digital computers, for example, always have an upper bound to the magnitude of the numbers they can handle. This number might be very, very large, but it is some specific finite number. (Software engineers like me must routinely take account of these bounds.)
3. There is no upper bound to the magnitude of the numbers the human mind can think. This can be proven by induction. Given any number x, the mind can think of x+1. Of course, I can't actually think all of these numbers as in a sequence, but that is beside the point. The critical point is that there is no bound to the numbers I might think.
4. Because the human mind is not bounded, it cannot be physical.
Notice that points like the following do not impinge on my argument:
I am not a dualist in the Platonic sense. I accept Aristotle's theory that the soul is the form or principle of the body. What exists is man, a substantial unity of body and soul. It is no surprise under this view that the body can affect the soul just as the soul can affect the body. It was no surprise to Aristotle. In fact, Aristotle claimed that the soul must be affected by the body in order to function.
The argument I gave above about the unbounded nature of the human mind is not original with me. I got it from Aquinas and Aristotle. What I find most fascinating about the mind/brain debate - and I've had this argument with many people over the years - is that physicalists tend to assume that the belief in an immaterial mind must be due to intuition or superstition or religious faith. In my experience, the arguments of Aquinas and Aristotle for the immaterial nature of the mind are not so much refuted as simply ignored or forgotten.
You wrote:
A physicalist account of mental phenomena should not have to issue a catalogue of every future state of every mind in order to be the correct view, any more than a physicalist account of the weather is invalid because it doesn't predict which trees will blow down in next summer's hurricanes. All I am arguing for here is the possibility that the reaction of the man upon coming to know that a physicalist theory of mind had been proven would itself be a purely physical event.
I think you may have missed the point of my argument. The point is that, when a complete theory of the behavior of man is finished and understood, man can contradict the theory simply by doing the opposite of what it predicts! That's what I meant by the theory needing to take account of the response of man when he comes to know the theory. If the theory says that given A, B and C, I will choose to do X, then in that case I will do Y instead. This is another case of the unbounded nature of man. Any physicalist theory, since it assumes that the nature of man is finite, must assume that his behavior is bounded and therefore ultimately predictable. But the nature of man is not so bounded, because he transcends predictions by knowing them.
I'm enjoying the conversation as well! I hope Bill, who has been silent here, doesn't mind us sucking up so much storage and bandwidth.
As for the objections you raise:
In the this number-counting example, you make two assumptions that fail to differentiate our brains from what a computer might do. First, you assume that we actually would be able to conceptualize a number of any arbitrary value. The notion is intuitively appealing, but do think you could hold in your mind a number a trillion digits long? Certainly we can memorize long texts - among Muslims, for example, a Hafez is one who has memorized the entire Koran - but your assertion that the human mind is capable of such feats without limit is, I think, completely unwarranted. Meanwhile, an ordinary computer could do this, given enough memory; keep in mind that the size of the memory representation of a data type is a mere convention (and of course we could use arbitrarily long text strings as well).
I realize that your argument attempts to avoid relying on mere memory usage, and is an attempt to show that the human mind can accommodate a literally infinite number of distinct concepts, but the number example won't do, because the numbers get unmanageably large. And in the more general case: as long as the brain can reconfigure itself to hold new ideas as needed, that doesn't mean that previous contents aren't going to be discarded to make room, if we really get to the point where the vast state space of a human brain is used up. The plenary and infinitely extensible nature of the human mind is, I think, nothing more than an alluring "user illusion".
As for the second example, you are, it seems, describing the following hypothetical senario:
1) A complete physicalist theory of the brain/mind system exists, and we have the technology to apply it to individual subjects.
2) We have before us a test subject whose total brain state is known to us. We also control in every detail any environmental factors that would impinge on his brain state. In other words, we have all the information we should need to predict his behavior.
3) The subject confounds us by acting in a way that is at variance with our prediction.
But if we are given 1) and 2), why should we believe that 3) is possible?
Perhaps your point is that once our subject knows what behavior the theory predicts then he can deliberately violate it. But of course, this would require an adjustment in 2) to accommodate the change in state caused by the subject's acquisition of the knowledge.
Clicked too soon, and posted a poorly-revised paragraph there. Better is this:
Yes, Bill has been patient... I appreciate it.
I'm going to respond in two posts.
The first is to say that I have a lot of sympathy for your position. My formal education is technical, in physics and electrical engineering. I work as a software engineer. I've always been impressed with the achievements of science and, at one time, thought that if anything could be explained, then the scientific method would be the way it would be explained.
It was only after many years in software engineering, and experiencing the limits of machines firsthand, that I began to wonder if the human mind is really like a machine. The problem is not one of holding in hand an infinite number of things, but one of representation. A computer has a limit on the magnitude of numbers it can represent, 10^308 being a typical limit. If the computer tries to add 1 to 10^308 it will overflow its adder and "bad things" will happen, bad meaning something like a program exception and possibly a crash. But I have no problem adding 1 to 10^308, or multiplying it by 10 or dividing it. To me, it's just another number.
It occurred to me that this is never a problem for physicists. They never worry that they will write down on the blackboard a number too large for our brains to handle and cause us all to have a nervous breakdown. They bandy about numbers like 10^79 (estimated number of electrons in the universe) just like any other number. Is there some magic number that, if someone tried to represent it, our brains would overload? It doesn't seem to me like there is. If I can represent X, whatever it is, I can represent X+1. I began to wonder if maybe the assumption that our minds are simply fleshy machines really squares with what our minds can do.
Supposs, for the sake of argument, that I am immortal. Then suppose that a computer and I start counting. Eventually, after a long time, the computer will experience an arithmetic overflow and be unable to continue (or it will start counting over from 1 again.) Would this happen to me? Or can I simply keep on counting forever? If the alleged "last number" I can count to is x, why can't I count x+1? It seems obvious to me, as it did to Aquinas, that there is no number in principle to which we can't count. And if that's true, our minds cannot be merely physical, because then there would be a limit.
In your description of the scenario, I believe it is your last sentence that has world-shattering implications:
That is exactly right. And when 2) is adjusted, the subject must be made aware of the adjustment as well. This will require a further change in 2) which, when the subject learns of it, will require a yet further change in 2), etc., etc. This process never comes to an end and the theory is never finished. The subject is never captured by the theory.
Now you might think it is cheating for me to insist that the subject know every revision to 2. But I claim exactly the opposite is true: It is cheating to withold information from the subject, for then the success of the experiment depends on the subject's ignorance. My claim all along has been that man as a knowing and willing creature cannot be ultimately captured by a scientific theory. It is true that the behavior of man, when he is ignorant, can be reliably predicted by science. Psychologists, jury consultants and advertisers do it all the time. When man wills in ignorance, his will is subject to scientific prediction and manipulation. But when man knows, he becomes empowered and his will liberated. You shall know the truth and the truth shall make you free. I believe that last sentence is empirically verifiable.
I think we are beginning to talk past each other a bit at this point, but I'll have a go at responding to your last comments.
Yes, our brains are flexible in ways that Windows XP is not. As it happens, I am a software engineer also, so I too am well familiar with the limitations of computers. As a software engineer you realize, of course, that the upper bounds on integer sizes you have been describing are merely conventions of implementation (simply due to the number of bits used for the representation of integer data types); one could in principle design a machine that used its entire memory just for the representation of a single, enormous integer, and the size of the number it could represent would be limited only by how much of the gross national product we wished to invest in hardware. So let's set aside the idea that there is an intrinsic upper bound to what computers are capable of.
Meanwhile, though, you seem to gloss over any of the actual implementation problems a human mind might run into in conducting the infinite "count to x + 1" experiment. Certainly there is no problem there conceptually, until we try to do this for real, and start dealing with numbers that are millions of digits long. You would simply not be able to hold such a sequence of digits in your mind. You would run into exactly the same problem a computer of arbitrary size would - at some point the representation of the number would be too large for your mind to handle.
For a scientist to use a number like, as you suggest, "10^79 (estimated number of electrons in the universe)" is simply a convenient shorthand, something the computer in your cell phone could do too, without breaking a sweat. The notion that you could actually enumerate individually such a set, holding its members separately in mind is, on the other hand, clearly beyond human capacity.
As for your second objection, you seem to be missing the deeper and more subtle point. Yes, as you point out, given the scenario I outlined (and have copied again below) we could indeed get into an endless and pointless loop - in which I assess the state of the subject, then inform him of my new assessment of his state, which then changes his state, and so on. But there would be no need to go about it in this way.
Recall the conditions we are discussing:
First of all, if you are in fact conceding that the only recourse for the sort of freedom and creativity you are arguing for is for us now to inform the subject of some new information, thereby changing his state, and that if we don't, he might indeed be as predicatable as I have suggested, then you have already agreed, it seems to me, to the idea that we can make a causal physicalist account of the subject's behavior.
But, even given your new priviso: once we satisfy conditions 1) and 2) above, it would be possible to predict the change in state that would result from describing the subject's acquisition of the knowledge we propose to offer him, and therefore we would not have to go "back to the drawing board" again and again, but would rather know in advance what he would do once informed.
But I think we have beaten this poor horse just about to death.
Let me ask you a question. What if we aren't as uncausedly free, or as absolutely infinite, as you would like to think we are, but instead are immensely complex physical systems, nevertheless replete with rich and dynamic intentionality, able to respond to our ever-changing environment with magnificent flexibility and nuance, autonomously able to select, from an astronomically enormous repertoire of behavior, actions based on our past experience, hopes for the future, and our consideration for those we care for? Would that be so bad? Would it feel any different?
I don't think we are yet talking past each other... at least, I think I understand the points you are making. At the risk of trying your patience, I've got to respond once more:
Of course we can increase the upper bound for any given computer by increasing its hardware. But any actually existing computer must have a finite amount of hardware resources, and therefore a finite limit to the numbers it can represent. This is the distinction Aristotle made between the potentially unbounded and the actually unbounded. My claim is that our minds, with the just the number of brain cells we have now, are not limited in the magnitude of numbers it can represent.
We must be careful to distinguish between the imagination and the intellect. Of course, our minds are very limited in the numbers they can imagine. I can't picture much more than 20 or 30 things in my head, or hold a long string of digits in it. But we don't have to do that to understand a number and use it. We can simply change our representation to a more convenient form. On this score, you wrote something of deep signficance:
Exactly. We create the conventions that the computer implements, and the computer is stuck with those conventions and is therefore limited. But our own minds are not limited by the conventions we create. We can change our convention to suit our purposes and needs. So when the computer's convention reaches its limit, it's out of luck. When my convention reaches its limit, I change it! If the decimal convention becomes inconvenient, I'll invent something else, maybe a convention no one has seen before. Adding hardware to the computer doesn't really change the nature of the problem, as Turing famously showed.
For the last point:
if you are in fact conceding that the only recourse for the sort of freedom and creativity you are arguing for is for us now to inform the subject of some new information,
I deny that this is a new concession on my part. My insistence all along has been that the distinctive feature of man is his knowing nature, and it is through his act of knowing that man becomes free. This is the central truth of the classical philosophers from Plato to Aquinas. In my opinion, much of the tragedy of the modern world can be traced to the eclipse of this truth from modern thought.
My difficulty with the physicalist theory is not that it feels bad or would make me feel differently, but that it is false. I also think that it is, in its falsehood, dangerous. Freedom is a peculiar thing. If you have it, but don't think you do, then you don't have it. Freedom to be real must be known as freedom (another way that freedom and knowledge are related). If the physicalist theory is correct, then ultimately our freedom is an illusion. Even if the physicalist theory is not true, but people believe it is, then they will not be truly free because they will not know their own freedom. They will remain chained to their seats, staring at the images, even though nothing prevents them from getting up and walking out of Plato's cave.
This is, in fact, what I think has happened. I see the consequence in my children's education, where many of their "educators" seem not to know the distinction between education and training. They seem to think a student well-drilled in mathematical or laboratory techniques is well-educated, when in fact they are merely well-trained, like basket-weavers watching the shadow-images in Plato's cave.
I've been on my soapbox long enough... I appreciate the conversation and I wish you well!
Sincerely,
David
I can't resist one more comment... dust off that soapbox!
A few years ago I read the book How We Believe by Michael Shermer. Shermer is a skeptic, a physicalist who believes that ultimately everything is the result of physical causes. The book itself is an explanation in evolutionary terms of how things like religious belief and superstition come about.
Anyway, near the end of the book Shermer gives his idea of freedom, which seems to be something like yours (at the risk of speaking for you!) Shermer says that, while we are not free in an ultimate sense because we are finally the result of material causes, we appear to be free because of the vast complexity of our brains and the contingency in the universe. We are so complex that we will never figure ourselves out and so can live as though we are free. And that is enough, because we can live our lives in light of this apparent freedom.
What struck me about Shermer's view is that it is exactly the opposite of the classical view. Shermer's view is that finally it is ignorance that makes us free, ignorance of the ultimate causes that make us what we are. The classical view is that it is truth that makes us free, and the more we know of the ultimate causes of things, the more free we will be. Is it truth or ignorance that makes us free? That seems to me to be what is at stake in this debate.
As for the computer being unable to reconfigure itself to change its representation of numbers as needed, whereas we are able to do so, you haven't made a convincing case that the difference isn't just one of hardware, software, and complexity. In fact my HP calculator does do exactly that - when the numbers get too big it automatically switches over to scientific notation.
We are simply not in a position, I am afraid, at our current state of knowledge and development, to prove the truth or falsity of dualist models of mind. You flatly declare that physicalism is false - a stronger claim than I am making about dualism - but I think you are deceived by the apparent boundlessness of our minds into thinking that they are infinite, which is another matter entirely. The Earth's surface is unbounded; a person could wander forever and never find the "wall" that limits it; but it is still finite.
You wrote:
Why does this distinction matter? How would the "real" freedom you are describing (and this idea is not as clear and simple, upon closer examination, as people think, but that would be another hundred comments from each of us) make our lives different in any way from the lives I am arguing that we already enjoy as living, thinking, choosing, loving, hoping, striving physical systems? I'm still going to have to go out and make thousands of choices every day - moral choices, choices of words and actions - choices that matter. And each and every one of those choices comes from my brain, my mind.
I'm with Shermer. Dennett has also argued this view very persuasively in his two excellent books on the freewill problem, Elbow Room and Freedom Evolves. But I have a sneaking feeling that you aren't a big Dennett fan...
I'll let you have the last word.
I will do you the courtesy of granting you the last word. I've enjoyed the conversation and I'm sure we will lock horns again sometime on this blog!
All the best,
David
Very gracious of you, and all the best to you as well.
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