Читать книгу The Philosophy of Philosophy - Timothy Williamson - Страница 20

The argument so far has reached two conclusions at first sight hard to reconcile with each other. First, the original question is not about thought or language. Second, to answer it adequately one must assess rival theories of vagueness in thought and language. How can that way of reaching an answer be appropriate to the original question? We might, therefore, find ourselves tempted back to the idea that somehow the original question was surreptitiously about thought or language.

On further reflection, the combination of the two conclusions is less surprising. Many non-philosophical questions that are not about thought or language cannot be resolved without inquiry into thought or language. Suppose that a court of law must decide whether Smith killed Jones. The question is not who said or thought what. Nevertheless, the crucial arguments may be over whether to trust the witnesses’ testimony. How is what they say now related to what they think now or thought then? How is what they think now or thought then related to what actually happened? Are they lying or sincere? Are their memories confused or clear? Those are questions about their thought and speech. They hold the key to whether Smith killed Jones, even though that question is not about thought about language.¹² Of course, the questions about the thought or talk are not about it in isolation from what it is thought or talk about: they are relevant because they concern the relation between the thought or talk and what it is about.

The court must decide the issue on the evidence before it. In a criminal case, does the evidence put it beyond reasonable doubt that Smith killed Jones? In a civil case, does the evidence make it more probable than not? If the court is really deciding a question about testimonial evidence, that is already a question about talk.¹³ But the question about the evidence arises in virtue of its bearing on the primary question, whether Smith killed Jones. Indeed, the question about the evidence is exactly a question about its bearing on the primary question. So the point stands.

Historians are often in a similar position. They want to know what happened. The way to achieve that is largely by considering documents, linguistic accounts of what happened – not in isolation, but in relation to what they represent. Most obviously, historians want to know whether the documents accurately represent what happened, but to answer that question they must in turn ask about their provenance: who produced them, when and why? Thus the history of the events of primary interest requires a history of thought and talk about those events. Those histories typically overlap, for thought or talk about some part of a complex human event is often another part of the same complex event.

Something analogous occurs in the methodology of the natural sciences. We wish to know the value of some physical quantity. We must devise apparatus to measure it. We may find ourselves in disputes over the functioning of different devices. Although the primary question was not about those measuring devices, we cannot answer it adequately without considering them. We need a theory about the relation between the value of the quantity and the representations of it we record when we use our instruments. The scientific investigation of the physical quantity widens to include the scientific investigation of its interaction with our experimental equipment. After all, our apparatus is part of the same natural world as the primary topic of our inquiry.

These analogies make it less surprising that when we try to answer the original question, which is not a question about thought or language, our main task is to adjudicate between rival theories of vague thought and language. A theory of vagueness validates some deduction that concludes with an answer to the original question. That deduction uses but does not mention vague thought or language. It is formulated at the logical level, like the original question itself, not at the metalogical level. But discursively to justify trusting that deduction, rather than one that reaches another conclusion by other rules, one must assess the rival theories of vagueness.

That theories of vagueness conflict in their answers to the original question shows that they are not confined to claims about thought and talk. Theories such as epistemicism and supervaluationism which employ classical logic have ‘Mars was always either dry or not dry’ as a theorem, once they are formulated in a suitably expressive language. To reiterate, that theorem is not about thought or talk.

For the three-valued and fuzzy approaches, the matter is only slightly more complicated. Their proponents assert:

 (C) It is indefinite whether Mars was always either dry or not dry.

On those approaches, C does not count as about thought or language. Strictly speaking, however, C does not follow from the three-valued or fuzzy theory of vagueness itself; for all the theory implies, there was never any liquid on Mars, in which case it would always have been either dry or not dry, even by three-valued or fuzzy standards, and so would not have been indefinite. The theory implies only a conditional theorem:

 (P1) If it was once indefinite whether Mars was dry then it is indefi- nite whether Mars was always either dry or not dry.

Three-valued or fuzzy theorists can combine P1 with what they regard as an empirical truth about Mars:

 (P2) It was once indefinite whether Mars was dry.

From P1 and P2 they use the rule of modus ponens (from “If P then Q” and “P” infer “Q”) to infer C, the answer to the original question. Although their theorem P1 does not answer the question by itself, it is no more about thought or language than C is. Their theories are just as committed as classical ones to making claims that are not about thought or language.

In principle, just as the considerations relevant to adjudicating the dispute between theories of vagueness are relevant to answering the original question, so too may they be relevant to answering a question asked with no philosophical intention, such as “Was Mars always either uninhabited or not dry?,” if it turns out to involve a borderline case. In practice, non-philosophers are often quite content to be told “It’s unclear,” without wondering exactly how that statement addresses the question asked; they simply drop the matter. For their purposes that may be the best thing to do. By contrast, philosophers persist; they want to know at least whether there is a right answer, even if nobody can know what it is. The difference lies not in the content of the original question but in the interests with which it is asked. Those interests can amount to a tissue of associated questions: for our original question as asked by a philosopher, the associated questions query other instances of the law of excluded middle. Given those interests, it is rational to persist with the original question, and not take an unexplained “It’s unclear” for an answer. But we should not underestimate the importance outside philosophy too – in science and even in politics – of sometimes persisting with a straight question, not allowing oneself to be fobbed off with the convenient claim that no practical purpose would be served by answering it. At other times, non-philosophers in effect assume without argument a particular treatment of vagueness (not always the same one), without realizing or caring that there are alternatives. The treatment may be good enough for their purposes, or not.

In this case study, our interest in giving a clear and critically reflective answer to a simple, non-technical, non-metalinguistic, nonmetaconceptual question forced us to adjudicate between complex, technical, metalinguistic, and metaconceptual theories. This phenomenon seems to have been overlooked by those who complain about the “arid” technical minuteness of much philosophy in the analytic tradition. A question may be easy to ask but hard to answer. Even if it is posed in dramatic and accessible terms, the reflections needed to select rationally between rival answers may be less dramatic and accessible. Such contrasts are commonplace in other disciplines; it would have been amazing if they had not occurred in philosophy. Impatience with the long haul of technical reflection is a form of shallowness, often thinly disguised by histrionic advocacy of depth. Serious philosophy is always likely to bore those with short attention-spans.¹⁴

Why should considerations about thought and language play so much more central a role in philosophy than in other disciplines, when the question explicitly under debate is not itself even implicitly about thought or language? The paradigms of philosophical questions are those that seem best addressed by armchair considerations less formal than mathematical proofs. The validity of such informal arguments depends on the structure of the natural language sentences in which they are at least partly formulated, or on the structure of the underlying thoughts. That structure is often hard to discern. We cannot just follow our instincts in reasoning; they are too often wrong (see Chapter 4 for details). In order to reason accurately in informal terms, we must focus on our reasoning as presented in thought or language, to double-check it, and the results are often controversial. Thus questions about the structure of thought and language become central to the debate, even when it is not primarily a debate about thought or language.

The rise of modern logic from Frege onwards has provided philosophers with conceptual instruments of unprecedented power and precision, enabling them to formulate hypotheses with more clarity and determine their consequences with more reliability than ever before. Russell’s theory of descriptions showed vividly how differences between the surface form of a sentence and its underlying semantic structure might mislead us as to its logical relations and thereby create philosophical illusions. The development of formal model-theory and truth-conditional semantics by Tarski and others has provided a rigorous framework for thinking about the validity of our inferences. These theoretical advances have enormous intellectual interest in their own right. They may have made it tempting to suppose that all philosophical problems are problems of language: but they do not really provide serious evidence for that conjecture.

To deny that all philosophical questions are about thought or language is not to deny the obvious, that many are. We have also seen how in practice the attempt to answer a question which is not about thought or language can largely consist in thinking about thought and language. Some contemporary metaphysicians appear to believe that they can safely ignore formal semantics and the philosophy of language because their interest is in a largely extra-mental reality. They resemble an astronomer who thinks he can safely ignore the physics of telescopes because his interest is in the extra-terrestrial universe. In delicate matters, his attitude makes him all the more likely to project features of his telescope confusedly onto the stars beyond. Similarly, the metaphysicians who most disdain language are the most likely to be its victims. Again, those who neglect logic in order to derive philosophical results from natural science make frequent logical errors in their derivations; their philosophical conclusions do not follow from their scientific premises. For example, some supposed tensions between folk theory and contemporary science depend on fallacies committed in the attempt to draw out the consequences of common sense beliefs.

Analytic philosophy at its best uses logical rigor and semantic sophistication to achieve a sharpness of philosophical vision unobtainable by other means. To sacrifice those gains would be to choose blurred vision. Fortunately, one can do more with good vision than look at eyes.

Many have been attracted to the idea that all philosophical problems are linguistic or conceptual through the question: if the method of philosophy is a priori reflection, how can it lead to substantive knowledge of the world? Those who find that question compelling may propose that it informs us of relations of ideas rather than matters of fact, or that its truths are analytic rather than synthetic, or that it presents rules of grammar disguised as descriptions, or that its aim is the analysis of thought or language. In short, on this view, philosophical truths are conceptuals truths. We may suspect the presence of empiricist presuppositions in the background – or, as with Ayer, in the foreground. Not starting with such presuppositions, we should be open to the idea that thinking just as much as perceiving is a way of learning how things are. Even if one does not fully understand how thinking can provide new knowledge, the cases of logic and mathematics constitute overwhelming evidence that it does so. The case of the original question, which is philosophical yet queries a theorem of classical logic, shows that we cannot segregate logic from philosophy and claim that armchair thinking illuminates the former but not the latter. In particular, conceptions of logic and mathematics as (unlike philosophy) somehow trivial or non-substantial have not been vindicated by any clear explanation of the relevant sense of “trivial” or “non-substantial.” Whether a given formal system of logic or mathematics is consistent is itself a non-trivial question of logic or mathematics. We know from Gödel’s second incompleteness theorem that the consistency of most standard systems of elementary mathematics cannot be decided in equally elementary mathematics, unless the original system is already inconsistent. The next two chapters investigate in more depth the prospects for conceptual truth and its role in philosophy.