Thursday, 20 August 2009

Swinburne Chapter 2: The nature of explanation

In Chapter 2, The Nature of Explanation, Swinburne looks at what constitutes an acceptable explanation for some phenomenon. He looks at three kinds of explanation

  • Scientific explanation
  • Personal explanation
  • Explanation by action of God

He starts by looking at scientific explanations. He starts by taking the most common kind of scientific explanation, which he calls a Hempel deductive-nomological explanation. In this kind of scientific explanation an event or current state of affairs is explained by the operation of natural laws on some set of initial conditions. The question arises as to where the laws have come from, and Swinburne mentions the “regularity view” originating from Hume, where the natural laws are simply the way things behave - in the past, present and future.

Swinburne finds overwhelming objections to the Humean approach.

Whether some regularity constitutes a law depends, on this account, not merely on what has happened but on what will happen in the whole future history of the universe, it follows that whether A causes B now depends on that future history. Yet, how can what is yet to happen (in maybe two billion years’ time) make it the case that A now causes B, and thus explain why B happens? Whether A causes B is surely a matter of what happens now, and whether the world ends in two billion years’ time cannot make any difference to whether A now causes B.

It seems to me that there is a very simple answer to this. By observation, it appears that this is how natural laws actually work - i.e. that they don’t change over time and as far as we can tell they were the same in the far distant past as they are now, and we have no reason to think that they will be different in the far distant future. It seems that Swinburne is confusing causes with effects. If the same law results in A causing B today as would result in C causing D in two billion years doesn’t mean that the A-B event is caused by the C-D event, but rather both have in some part the same cause - i.e. the operation of the same law.

Anyway, Swinburne goes on to describe another form of scientific explanation which he seems to prefer; the substances-powers-and-liabilities (S-P-L) account, where substances have the power to affect other substances around them, and the liability to exercise those powers under certain conditions. In other words, what we think of as being natural laws are merely the properties of substances. In this, he avoids the use of natural laws as universals. To me, it seems a bit of an angels-on-the-head-of-a-pin distinction, in that it doesn’t matter much whether we think of a law (such as gravity) as existing separate from mass, or of being a property of all massive objects. The equations work in just the same way in either case, and the earth is not going to stop moving round the sun just because you have changed the way you think about these things.

Swinburne claims that with the S-P-L account, there is no necessity to assume that because a particular piece of copper has the power to expand and the liability to do so when heated, all other pieces of copper will behave the same way. But the fact is that all pieces of copper do expand in this way, and again, there is no reason to expect that to change in the future.

Then Swinburne goes on to what he calls personal explanations, in other words explanations of events brought about by human actions. He goes at some length to describe intentions, decisions by humans that bring about some action. He uses the S-P-L account to claim that (unlike inanimate objects) humans are able to choose whether they will exercise their powers or not. He uses the term “event” as follows

An event consists in the instantiation of a property in a substance, (or substances, or in events) at a time or the coming into being or ceasing to exist, of a substance. Events include the table being square now, or John being taller than James on 30 March 2001 at 10.00 am, or me coming into existence on 26 December 1934. In order to fulfil the purpose of the definition of ‘event’, we need so to individuate properties that, if you knew what properties had been instantiated in what when, you would know (or could deduce everything that had happened.

Swinburne goes on to claim that personal explanations are unanalysable scientifically. This is a very big and bold claim to make. One would expect that such a radical hypothesis would be backed by some serious and substantial evidence. This is what he provides:

It follows immediately that having an intention cannot be the same event as having some brain event, for you could know that someone was intending to do such-and-such in his action without knowing that he was in a particular brain state, and conversely. These are two different events connected with a subject, even if perhaps of physical necessity they always go together. It is true that other criteria for the two events being the same event might yield a different result—that the two events were the same; but then, to tell the whole history of the world on those other criteria, it would not be enough to know that some event (for example some brain state) had taken place, you would need to know that it had two different somethings, say ‘characteristics’—a brain characteristic, and an intention characteristic—associated with it. Some sort of dualism is unavoidable here, and I suggest that my proposed use of the word ‘event’ provides a neat system of categories by which we can describe the world fully, a system of categories not too distant from ordinary usage.

So, because you don’t know the inner workings of somebody’s brain, you have to conclude that the person’s brain state is not responsible for his intentions? This seems a remarkably thin line of reasoning, especially when such a momentous conclusion “Some sort of dualism is unavoidable here” is based on it.

It appears that it genuinely doesn’t occur to Swinburne that intentions are a property of the detailed workings of the brain, that we experience some of the operations of the brain as intentions, just as we experience other brain activity as emotions. He appears to regard intentions as sui generis, inexplicable in terms of the detailed operations of simpler entities. He’s perfectly aware of the concept in other contexts. When describing his understanding of the S-P-L account he says

The powers and liabilities of large-scale things (e.g. lumps of copper) derive from the powers and liabilities of the small-scale things that compose them (atoms; and ultimately quarks, electrons, etc.).

But it appears that he does not apply the same principle to intentions. He makes no mention of psychology in the whole book - the word simply does not appear in the index. Any physical (and scientific) explanation for how intentions might plausibly come about is not even actively rejected -in this chapter, it is not even mentioned.

Here is Daniel Dennett on the subject of intentions and how we interpret the world around us. He speaks of different stances used to understand aspects of the world.

The most concrete is the physical stance, which is at the level of physics and chemistry. At this level, we are concerned with things such as mass, energy, velocity, and chemical composition. When we predict where a ball is going to land based on its current trajectory, we are taking the physical stance. Another example of this stance comes when we look at a strip made up of two types of metal bonded together and predict how it will bend as the temperature changes, based on the physical properties of the two metals.

Somewhat more abstract is the design stance, which is at the level of biology and engineering. At this level, we are concerned with things such as purpose, function and design. When we predict that a bird will fly when it flaps its wings, on the basis that wings are made for flying, we are taking the design stance. Likewise, we can understand the bimetallic strip as a particular type of thermometer, not concerning ourselves with the details of how this type of thermometer happens to work. We can also recognize the purpose that this thermometer serves inside a thermostat and even generalize to other kinds of thermostats that might use a different sort of thermometer. We can even explain the thermostat in terms of what it's good for, saying that it keeps track of the temperature and turns on the heater whenever it gets below a minimum, turning it off once it reaches a maximum.

Most abstract is the intentional stance, which is at the level of software and minds. At this level, we are concerned with things such as belief, thinking and intent. When we predict that the bird will fly away because it knows the cat is coming, we are taking the intentional stance. Another example would be when we predict that Mary will leave the theater and drive to the restaurant because she sees that the movie is over and is hungry.

Dennett’s point is that you can always use the physical stance because everything obeys the laws of physics. But working things out (particularly complex things like humans) by the physical stance is time consuming, and by the time you have made your prediction the event under consideration is long past, so we use shortcuts.

The design stance is a shortcut, a rule-of-thumb that allows us not to concern ourselves with the physical characteristics of materials and look at their purpose, and predict their behaviour accordingly. It doesn’t matter whether an alarm clock is spring-wound or battery-powered, or by what means it keeps accurate time. Provided that you are familiar with alarm clocks, even if you haven’t seen a particular model before, a cursory examination will allow you to work out how to set the alarm correctly. Similarly, although birds’ wings are not actually designed, but have evolved in such a way as to be useful for flying, we can conclude that any creature with wings of a certain size relative to the creature’s weight is probably able to use those wings to fly.

The intentional stance is an even quicker shortcut, available for when we are dealing with things with mind and intention. We can predict a person’s likely next actions (or those of an animal for that matter) by analysing words (in the case of humans), facial expression, movement etc in order to infer his intentions.

Each of these two shortcuts allows for faster predictions, at the cost of being wrong sometimes. But an occasionally inaccurate prediction that a nearby lion intends to eat you and that it would be an extremely good idea to be somewhere else very quickly seems to me to have great survival value. If you sometimes get out of the way unnecessarily because in fact the lion isn’t interested in you, you have lost nothing except a bit of energy. If the lion catches and eats you while you are still working out its physical characteristics, you have lost everything.

So we have two diametrically opposed accounts here. We have Swinburne’s assertion that intentions are separate from physical events and inexplicable in scientific terms, and Dennett’s approach that phrasing explanations in terms of intentions (using the intentional stance) is a rough-and-ready shortcut to making predictions about the world around us that are accurate enough to have survival value.

The complexity and operation of the human brain is still largely a mystery to us. Neuroscience is still in its infancy and there is a huge storehouse of knowledge yet to be explored. So at the moment, the hypothesis that every intention is associated with a particular kind of brain event is a P-inductive argument, and scientists are looking at the linkages now in order to see what underlying laws might govern the operation of the human brain and mind.

One thing is certain. Brains do exist, and physical or chemical changes in and damage to your brain do affect your mind, including your thoughts and intentions. Brains are of such vast complexity that it will take time to unravel all of the connections involved. But it seems reasonable to have as a working hypothesis that our brains are the source of all our thoughts and intentions, and that our brains obey the laws of physics in their operation. There would only be a need to discard this hypothesis if we come across some other source of thoughts and intentions that is definitely unconnected with events occurring within the brain.

In essence, a large part of science is a process of unravelling the design stance (in biology) and intentional stance (in psychology and neurology) and reducing it to the physical stance and explaining these phenomena in terms of underlying physical laws. But this takes time and we have a long way to go yet.

So it seems to me that Swinburne’s inescapable dualism is not inescapable at all. We may not yet have all the answers, but not yet having the answers doesn’t mean that the answers are forever unobtainable even in principle, and that we need therefore to offer dualism as he only possible way to explain intentions.

I suspect that Swinburne wanted very much to make dualism seem an inevitable part of personal explanations in order to prepare the ground for his third category of explanation: “Explanation by action of God”. If human intentions are inexplicable in scientific terms and require a dualist worldview, then it becomes easy to suggest that some nonhuman disembodied mind also exists, and that this mind has intentions which are similarly inexplicable in scientific terms. Swinburne’s argument is that God is just such a disembodied mind, and that being wholly disembodied, God can directly affect any part of the physical universe with equal ease, and is able to know anything about the physical universe without being dependent on sense impressions impinging on some specific part of the universe.

So, Swinburne’s line of reasoning is that intentional actions (by humans or by God) are of a fundamentally different nature and require a fundamentally different non-scientific mode of explanation from physical events. A whole chapter of explanation seems to boil down to the fact that we don’t have a detailed understanding of the linkage between brain states and intentions, followed by an assertion that no such definite linkage exists, and a resulting conclusion that dualism is inescapable. This seems to me to be God-of-the Gaps reasoning, and as such it is susceptible to embarrassment with every advance made in neuroscience which might offer a causal connection between physical events in our brains and our conscious intentions.


  1. Swinburne's position is not as philosophically vaccous as you present it. It isn't that he thinks science will not identify brain states with mental states; indeed, he says it is a physical necessity. Rather, his point is philosophical, conceptual - science will do so by identifying a particular physical state with a particular mental state, it will always require both a physical and a mental property - two "characteristics", or whatever. The philosophical point is that mental properties cannot, philosophically/conceptually, be reduced to physical properties, and therefore you'll always end up needing both. Hence, "some sort of dualism is inescapable".

    In my opinion, Swinburne here fall into the trap of linguistics, that has felled many a contemporary philosopher - confusing the map with the territory. Language is merely a way we describe reality, it cannot limit what reality is. That we cannot conceptually deduce a mental from a physical property says something about the limitations of our deductive faculties and conceptual frameworks, not about the nature of reality. No dualism is required - all that is required is the recognition that at least some physical structures are identical with some mental states.

    However, I'm equally unimpressed with Dennett. The different "stances" don't explain mental properties, they explain them away. The conceptual dualism Swinburne distorts into an ontological dualism is distorted by Dennett, instead, into an empty illusion, a smoke and mirrors game. This is equally wrong. There is a deep conceptual difference between having a certain physical state and having a certain mental state, and understanding the connection between them is one of the hardest problems of philosophy (the Hard Problem as David Chalmers puts it), and eliminativism (Dennett's position) only serves to obstrucate this interesting issue.


  2. Just to clarify - the idea that human actions are exempt from scientific analysis is, of course, special pleading and deeply mistaken. Likewise, the idea that physical law isn't descriptive. It is the position that "some sort of dualism is unavoidable" that is is not completely without some reason behind it, although of course Swinburne takes that too way too far.


  3. Yair
    The philosophical point is that mental properties cannot, philosophically/conceptually, be reduced to physical properties, and therefore you'll always end up needing both.
    OK, that might be the route he is taking, but I don't see that renders his position any less vacuous. There is the physical explanation that mental properties are an emergent characteristic of physical properties of brains (just as the hardness of a table is an emergent property of the particular mix and arrangement of atoms within it).

    Swinburne is asserting that this reduction is impossible, that mental states are not reducible in this way, and concludes that dualism is inescapable. He provides no evidence beyond the bare fact of the assertion.

    Of course, Chalmers' "Hard problem" remains unsolved at present, but that doesn't mean that we should assume that it is forever insoluble even in principle, and that dualism is therefore the only viable hypothesis to explain the mind. If Swinburne wishes to argue that, then he should have provided some kind of line of reasoning to suggest why the reduction of mental states to physical states and the correlation between them is impossible even in principle. But he doesn't, and I suspect that he lacks the necessary knowledge of neurophysics to even make an attempt that goes beyond the Argument from Personal Incredulity.

  4. Of course, Chalmers' "Hard problem" remains unsolved at present, but that doesn't mean that we should assume that it is forever insoluble even in principle, and that dualism is therefore the only viable hypothesis to explain the mind.

    Swinburne is a sub-par philosopher, who wrote a sub-par book which doesn't justify itself properly. However, if you read Chalmers you will see that even he is skeptical of the eliminativist (Denett) or emergence solutions. They don't seem viable. This doesn't mean that dualism is justified - Chalmers points out several possible directions, my favorite being panpsychism. But even within such monism, "some sort of dualism is inescapable" in the linguistic sense - one has to posit that there are two aspects to reality, the physical and the mental. I think that merits the honor of being called "not entirely vacuous". Again, Swinburne does take this forced dualism too far, equivocating ontological and conceptual dualism in a sloppy and underhanded manner.

  5. Yair
    one has to posit that there are two aspects to reality, the physical and the mental. I think that merits the honor of being called "not entirely vacuous"
    In the way that Swinburne interprets this, I'll stand by my original description. He appears to be suggesting that it is impossible for the mental to be no more than a property of the physical - a way of describing events at a higher level of abstraction. He appears to be suggesting that mental events must have an existence separate from the physical events in the brains they are associated with.