Speaking of the truth...

One of the books I was given for Christmas was 'Think', by Simon Blackburn. This is a basic introduction to philosophy. It's one of the best books I've read. I wasn't bothered by the clear bias of the author, as it doesn't come from any attempt to coerce agreement. Instead, Blackburn seems to be motivated by the simple joy of exploring and sharing ideas. He explains, rather than demeans, ideas he disagrees with. The explanations are clear and captivating, and I was thoroughly drawn in.

To follow it up, I've been reading 'Truth: A guide', also by Blackburn. Once more, I was delighted by the clear exposition and fascinating range of ideas. I can't help but try to explain and extend some of them here. After introducing various understandings and rejections of truth, from absolute realism to postmodernism (which he managed to clear up some of my confusions about), Blackburn is reasonably explicit about where his allegience lies.

First, he notes that to say that a statement is true is simply to assert the statement. As a result, he counsels us not to get caught up in elaborate negotiations about the nature of truth itself, but to be content, when we hear claims of truth, to understand the intention of the speaker, namely to assert the statement which is being claimed as true.

Of course, this does not resolve the battles over the nature of truth. To recognise that the question 'Why is that true?' can be simplified to 'Why?' is not to see how to answer the question itself in any circumstance. The circumstance is important; there is no reason why we should not give different answers, or even different kinds of answer, to this question in different circumstances. The issue has been refocused as one of justification.

Blackburn then proceeds to look at various kinds of answer that can be given, and various reasons why we might not want to answer the question at all, or even believe that to be a sensible thing to attempt. Though the arguments and ideas he outlines are interesting, and provide historical perspective, you should look in the book to find out what they are. Blackburn takes inspiration from them, but it is what he goes on to say that I'm interested in.

Blackburn zooms in on a kind of claim which does seem to be justified in a real way; by being a claim about the world, to which it corresponds. That is, he looks at the claims of science. Why do we say that these claims are about a real world? We do so in order to account for the quality of the success of science. We find that people who use a map to find water are more successful than those who use a dowsing rod. We explain this by postulating a real world, to which the map corresponds. Here's how Blackburn puts it:

Suppose my practice is successful: my space rockets land where and when they should. What is the best explanation of this success? I design my rockets on the basis that the solar system has the sun at its centre, and it does. Why is our medicine successful? Because we predicted that the viruses would respond in such-and-such a way, and they do. In saying these things we are not at all stepping outside our own skins and essaying the mythical transcendental comparison. We are simply repeating science's own explanation of events. There is no better one - unless there is a better scientific rival. Once we believe that the best explanation of geographical and optical data is that the world is round, we also believe that the best explanation of our successes as we proceed upon this hypothesis is that the world is round. It is not that there was a further set of data about science (its success) that required something like an independent, sideways explanation. It is just that the very regularities in the phenomena that required the theory in the first place should now be looked on as including any success we have in using the theory. Shadows fall at night because of the revolution of the earth, and success awaits those who expect shadows to fall at night because of the revolution of the earth. Science explains the success of science.

Blackburn notes an obvious objection: There are alternative explanations of the success of science. For example, 'Any scientific theory is born into a life of fierce competition, a jungle red in tooth and claw. Only the successful theories survive.' But these explanations are not mutually exclusive; they are complementary. It may well be the case that a scientific theory survives precisely because it is a description of the way that the world is. Indeed, a glance at the history of science suggests that this is the best explanation of what is happening.

Another objection is that this only allows us to accept the empirical adequacy, or the accuracy, of science, not to go so far as to call it true. Blackburn argues that this is a false distinction. He carefully examines several ways we might try to separate empirical adequacy from truth: All are found wanting.

Blackburn says 'We are simply repeating science's own explanation of events,' and he is right. But he appears to conclude that therefore the actual giving of this explanation is a task for scientists, rather than philosophers; that philosophy has nothing helpful to say here. This is because the account he gives is a little oversimplified.

Scientists explain the world by making models of it. Nowadays, these models are often highly abstract and mathematical, but they need not be so abstract nor so detailed. For example, a gas is modelled as a large number of atoms, all jostling around and banging into one another. This model was introduced to explain the behaviour of the gases that we observe, and it does this extremely well. The model talks about individual atoms. What are these atoms? It makes no sense to try to answer this question from outside the model. When we discuss atoms, we are using the model, not just mentioning it. For example, to say that the atoms are aspects of the observations which led us to introduce the model would be to stretch language beyond breaking point. It would be to mix levels, and to confuse categories. Hopefully the mistake is clear in this case, but when there is a more subtle interplay of models it is an easy one to make.

Now let's return to what Blackburn says above: 'Shadows fall at night because of the revolution of the earth, and success awaits those who expect shadows to fall at night because of the revolution of the earth.' It is easy to make sense of the first part of this sentence. We have a model of the world as a slowly revolving globe with light coming from a particular direction. The globe has bumps on it, and within this model we can say things like 'the rotation of the earth causes these bumps to cast shadows at night.' Let's call this rather useful model 'model I'.

Model I is not sufficient for the second part of the sentence. There is nothing referred to by model I as 'those who expect shadows to fall at night.' We must consider a more complicated model, model II. Model II is like model I, except that it includes some observers. These observers have expectations, which may be successful or unsuccessful. Blackburn switches from model I to model II in midsentence.

This may appear to be pedantry at first, but awareness of this extra layer of complexity allows us to explain how this might tie in with some previous philosophical ideas. Let's return to the illustration of the theory of gases, based on a model involving atoms. As I'll be introducing more models in a minute, I'll christen this one model III for the sake of clarity. The most obvious model to introduce next, model IV, is one in which not only is there a gas, composed of atoms in the same way as before, but there are also observers, who make predictions on the basis of models. Some of these observers use model III, and model IV explains their success.

Suppose now that we consider the statement 'atoms are real'. It isn't a statement we can make within model III: Model III doesn't have a notion of 'reality'. Nor is it a statement about model III. Instead, it's a statement we can make within model IV. Model IV is something we might consider in order to explain the behaviour of scientists who study gases. As a part of this explanation, we may wish to say 'The scientist successfully predicted the behaviour of the gas because he used the atomic theory, and the gas really is made of atoms'. It is in a context like that of model II or model IV that Blackburn's explanation 'I design my rockets on the basis that the solar system has the sun at its centre, and it does,' makes sense.

You may smell a rat at this point. If the idea of reality is introduced to explain the behaviour of scientists, isn't that saying that, for example, the reality of atoms consists in nothing more than the success of scientists who use models like model III? No. To say so would be to make a category error like that described 5 paragraphs ago. In saying 'Atoms are real' we use model IV. but the success of certain scientists is what model IV was to explain; it is not something within the model itself.

The other philosophical mistake which is clarified by this approach is Dualism. After all, a crude model including observers would have the observers being genuinely different to that which is observed. But, remarkably, this is not a necessary feature of such models. Indeed careful study of the observers we are most familiar with, ourselves, suggests models in which the observers are of precisely the same stuff, and the observation is itself a process obeying the same laws as that which is observed.

Now we can return to the claim that we can only ever get at empirical adequacy. We could, for example, consider a complex model in which some observers study a real world and have theories about it which are accurate but wrong. For example, gravity may really behave according to the theory of relativity, but the scientists could be working with Newtonian mechanics. As long as they don't measure too precisely, the scientists will make successful predictions. Their theory is empirically adequate but not true.

This is just the kind of situation most scientists think we are in at the moment. All the evidence suggests that quantum electrodynamics is both extremely accurate and false. It's just a really good approximation. However, because it is a good approximation, coarse-grained statements it makes will be true. The scientists in the model above may be working with a false theory, Newtonian mechanics. But the broad-brush statements they make, like 'the gravity of the moon causes tides twice every day', are nevertheless true of reality even in this model. That is just what it means to say that they are working with a good approximation.

So we can accept that our best and most detailed scientific theories are no more than unbelievably good approximations, and still say that the cruder claims of science, such as 'stuff is made of atoms' are true. It is within this kind of model, of a real world which we have a good but imperfect approximation to the workings of, that we can say things like 'chairs are real'. Luckily, this kind of model also gives a great explanation of what we observe.

The key feature of these expanded models is that they are modelling us, the observers. In particular, they model us as somehow making models of the world. One key tool we use is language. So the model must include some account of how we use language to talk about the world. For this reason, though possibly not aware of it in these terms, philosophers have made a careful study of how we use language, and how our linguistic behaviour relates to the meanings we intend. This study of language-games gives philosophers a head start in producing good higher-order models. So philosophers need not merely recount science's own explanation: They can add their insights to it.

One example is the study of truth and falsity. Blackburn appears sympathetic to the quietist position:

We should leave truth alone. We sould not enter the fields of meta-theory or philosophical reflection, to try to say something more, to gain a 'conception' of truth, as both absolutists and relativists have been presented as doing.

This is fair enough, to a degree. But if we are to make models like those above, which include notions of truth, then good models will have some conception of truth; of how it works. For example, they ought to include some notion of logic; of when it is that we can deduce some statements from others. Again, philosophers have made progress here. A lot of their work has fed into detailed mathematical models of deduction.

There has been a remarkable development in recent years. Aspects of the most detailed models we have of the world are being combined with the most intricate models of truth mathematicians have come up with. Both the physics and the mathematics have been slightly tweaked. The claim is that, just as notions like position break down at a small scale, and are only useful as approximations, the same is true of notions like truth and reality. It is not at all clear whether this exciting attack can be made coherent, but it should be worth watching to see.

I have talked in detail about physical truth; truth about the world. What about moral truth? Do we have a similar model, of moral statements corresponding in some sense to reality? Well, such models do exist, but their acceptance is on the wane. There has been a lot of work in the last century on how evolutionary processes could produce beings who speak and feel as we do about morality, in the absence of a moral reality to which they refer. These models are still crude, but they do seem to have explanatory force.

Leaving aside the question of whether such models are accurate, it is worth drawing a consequence from their nature. It is from within such models that we might make the statement 'Morality is relative, and not absolute'. Accordingly, this statement is about the world, about the way that things are. It is not a moral statement, and so it does not have direct moral consequences. In particular, from 'Morality is relative', we cannot deduce things like 'Anything goes'. 'Anything goes' is a moral statement; it does not form a part of such models of moral behaviour.

It is not necessary to use these ideas to see that moral relativism has no moral consequences. Indeed, I'll conclude with Blackburn's able exposition of this theme:

Suppose I believe that foxhunting is cruel, and should be banned. And then I come across someone (Genghis, let us call him) who holds that it is not cruel, and should be allowed. We dispute, and perhaps neither of us can convince the other. Suppose now a relativist (Rosie) comes in, and mocks our conversation. 'You absolutists,' she says, 'always banging on as if there is just one truth. What you don't realise is that there is a plurality of truths. It's true for you that foxhunting should be banned - but don't forget that it's true for Genghis that it should not.'

How does Rosie's contribution help? Indeed, what does it mean? 'It's true for me that hunting should be banned' just means that I believe that hunting should be banned. And the opposite thing said about Genghis just means that he believes the opposite. But we already knew that: that's why we are in disagreement!