Nature and convention
In the previous chapter we investigated the epistemological roots of relativism. Now we turn to more metaphysical considerations.
The distinction between nature and convention does more than record the facts of variability in belief: it suggests an explanation. In the case of matters belonging to nature, the universality of belief is explained by the existence of 'hard facts': facts that obtain independently of what we think or believe. Such facts are found, not made. In the case of matters that are customary or 'conventional', our judgements and responses are not answer able to any such external standard. Our standards of morality, say, are made, not found. There is no question of one group's being right and another's being wrong, the argument continues, for there is nothing to be (objectively) right or wrong about. This is another route to a position that might be thought of as relativistic. The thought is not so much that truth is relative as that, in some areas of discourse, the notion of truth gets no real purchase, so that any view is as good as any other. Plato's opponents, the Sophists, seem to have adopted a kind of relativism on something like these grounds: they offered to teach the art of speaking well as a neutral skill, adaptable to the values and customs of whatever city the pupil found himself in. Plato, by contrast, thought that even in matters of value, there are ultimate universal and objective truths that, with sufficient diligence, we might hope to discover.
One of the fundamental tasks of philosophy has always been to determine what belongs to nature. This is another way of understanding the task of metaphysics, as the investigation of what is ultimately real. A certain concep tion of nature as what is there anyway, independently of human perception, custom, or artifice, gives content to this metaphysical concern. However, philosophers who have taken up this task-with the possible exception of certain Idealists-have tended to assume that something belongs to nature, so that there are significant demarcational lines to be drawn. In particular, philo sophers in the analytic tradition, whatever their views of moral or aesthetic judgement, have tended to view science 'realistically'. The goal of science,
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which it sometimes reaches, is to discover facts that belong to nature. This is what makes science objective and capable of progress.
Whereas philosophy of science used to concern itself with highly abstract questions about explanation and confirmation, many contemporary students of science take an interest in the historical and sociological details of scientific research. The main impetus for this historical and sociological turn, at least for philosophers of science, comes from Thomas Kuhn's theory of 'scientific revolutions'. Kuhn's writings have probably had more impact-especially out side professional philosophical circles-than any other writings concerned with broadly epistemological issues. But Kuhn's views seem scandalous to many philosophers, and one of the main reasons is that they appear to chal lenge the realistic perspective. On a certain reading, which his rhetoric does a lot to encourage, Kuhn's social-historical account of scientific change implies that 'scientific facts' are just claims that (reputable) scientists endorse. The 'facts' are, so to say, made in the laboratory. To use a phrase that is popular today: scientific facts (or 'facts') are socially constructed.' For realists, to take such a position is to give up on the notion of fact altogether.
Has Kuhn really given us reason to think that scientific facts are made rather than found? This is an important issue for me, since Kuhn's picture of science has a definite contextualist slant. Discussing Kuhn's ideas will be a way of further clarifying what a con textualist ought to say about notions like truth and progress.
The two-phase model
Kuhn's views develop out of sharp criticisms of what was, when he wrote, the standard empiricist account of science. Standard empiricism embodies sub stantive foundationalism. It postulates a fixed 'observation language' capable, in principle, of capturing any empirical finding, and connected to theoretical statements by an inductive logic (or rules of confirmation) . Kuhn finds this picture to be wildly at variance with the actual practice of science. Scientific observations never take the form of the foundationalist's reports on simple sensory occurrences, but are 'theory laden'. The telescopic observations used by Galileo to confute the Aristotelians are bound up with complex assump tions having to do with optics: this penetration of observation by theory is typical. Also, theories play a role in determining what observations are rele vant to their confirmation. It used to be thought important to explain the number of the planets, but after Newton no one thought this any more. Newton's theory was so successful that facts it couldn't explain became not worth explaining. But this decision on the part of the scientific community was not, in any simple way, mandated by Nature.
Kuhn also objects to Popper's idea that science aims constantly at refuting theories. Such a policy would be destructive of science. Even the most
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successful theories are 'born refuted', in that there are typically many phe nomena that, it seems, the theories ought to be able to explain but can't. Some phenomena may even amount to Popperian refutations. However, researchers treat them as 'anomalies' rather than counter-examples. The existence of anomalies is not a signal to reject a theory but a challenge to develop it further. In any case, testing a theory is by no means as simple as Popper's writings sometimes suggest. As science becomes more sophisticated, devising ways to subject theories to experimental test is itself a challenging undertaking. Refutation is never routine.
These reflections lead Kuhn to a two-phase model of scientific change. A striking achievement like Newton's mechanics constitutes a 'paradigm' around which future research crystallizes. This crystallization gives rise to 'normal science'. In normal-scientific research, the fundamental assumptions, theoretical and methodological, implicit in the paradigm-what Kuhn later calls a 'disciplinary matrix'-are simply not in question. The challenge for normal science is to further refine the theory, to take care of apparent anomalies, and to extend its application to new phenomena. Normal science's characteristic activity is not debate about fundamentals but 'puzzle solving'. However, for even the most successful theory, a time comes when anomalies begin to accumulate at a rate that taxes the ingenuity of even the theory's most devoted adherents. At this point, investigators begin to look for alternatives. Science now enters a revolutionary phase, in which there are no rules to guide research. If a new theoretical paradigm emerges, the grounds for preferring it will not be straightforwardly observational but will also involve broad holistic considerations of economy and elegance. Once the new theory is in place, erstwhile anomalies come to be seen as refutations. A scientific revolution has taken place and a new period of normal science begins.
Kuhn has a pronounced tendency to emphasize the non-rational elements in scientific change. For example, he notes that older scientists who have given their lives to a certain type of research may be unwilling to abandon it. The triumph of a new paradigm may therefore depend as much on this gener ation's dying off as it does on decisive confirmation or refutation, as more traditional philosophies of science understand such things.
This aspect of Kuhn's work has done a great deal to encourage the so-called 'strong programme' in the sociology of knowledge.2 According to this concep tion of science, scientific change is to be completely accounted for in terms of social factors: generational shifts, the politics of the laboratory, influences from the surrounding culture and society, and so on. This is an odd view. Sociology is supposed to show that physics is just a social construction, as if the social 'sciences' were in better shape than physics.
In fact, nothing in Kuhn's account of science, as presented so far, mandates such extreme reactions. Indeed, Kuhn's views are much closer to Popper's than they first seem. What obscures the similarity is that, whereas Popper
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remains mired in the methodological individualism of traditional epistemo logy, Kuhn is interested in scientific research as a socially institutionalized endeavour. Popper presents his falsificationist methodology as rules for how the individual scientist should conduct his investigations. Kuhn points out that this couldn't work. The normal-scientific testing of an advanced theory is a difficult business. Working out how to do it demands intense efforts from committed adherents, who will not regard the first disappointing result as a signal to go back to the drawing-board.
In revolutionary times, the situation is more fluid. But though anomalies are now potential counter-examples, there is no algorithm to tell us when to abandon the received view, or exactly how to trade off theoretical elegance against empirical precision. Sometimes it may be best if competing theories exist in tandem for a while, so long as all attract a critical mass of competent investigators (which means that there can't be too many options in play). Only this way can one theory eventually acquire decisive advantages over its rivals.
What all this shows is that it makes sense for the institution of science to tolerate investigators displaying a range of 'epistemic styles' and theoretical preferences: for example, some more empirically oriented, others inclined to place more weight on general theoretical considerations. Over time and trans personally, science may still function as something like a Popperian conjecture-and-refutation machine, though it will do so only if individual practitioners do not adopt a Popperian methodology. On Kuhn's model, sci ence works because, as an institution, it has managed to strike a delicate balance between freedom and constraint, and because its procedures, however theoretically mediated, involve interactions with nature that we do not fully control. Normal-scientific research is what throws up the anomalies that eventually provoke theoretical advance.
We should remember, too, that abandoning foundationalism allows us to see the observational/theoretical distinction as methodological, not onto logical. With advancing techniques of experimentation, theoretical entities cross the line into the domain of the observable.
I do not mean that there is nothing to be learned from sociological analyses of science. However, we should follow Ian Hacking and distinguish between analyses that are refuting and those that are not. With regard to particular bodies of theory, we may well come to think that genuine empirical constraint is wholly lacking, so that the apparent credibility of such theories is com pletely accounted for in ideological, political, or other non-epistemic terms. By contrast, in other instances We may find that theories, though equally subject to such social-historical influences, pay their way, so that their credi bility is not exhaustively accounted for in non-epistemic terms. In my view, refuting analyses are available in connection with much of the theorizing that makes up the 'human sciences'. In abnormal psychology, for example, theories
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seem all too easily blown by the winds of fashion, changing with changes in what is thought to be 'normal' behaviour. But how we sort things out in particular cases is an empirical matter. Recognizing 'external' influences on scientific theorizing and non-rational factors in scientists' decision-making does not commit one to dogmatic, across-the-board relativism or social constructivism.
Different worlds
Given the way Kuhn's work has been received, surely I must be leaving some thing out. I am. What has made Kuhn an icon for sceptics and relativists (although Kuhn always repudiated the relativist label) is not his socialized Popperianism but his provocative remarks about how scientists on opposite sides of a revolutionary change live in 'different worlds', so that their theoretical views are 'incommensurable'.3
We should not read too much into this talk. Kuhn's scientists are not living in 'different worlds' in any sense of that phrase that conflicts with Davidson's strictures on global conceptual relativism. Galileo and his Aristotelian rivals could agree on lots of mundane facts: they disagreed about what 'world sys tem' best accommodated them. Furthermore, their disagreement extended into fundamental methodological issues: the questions a physical theory ought to answer, the importance (and appropriateness in physical matters) of mathematically precise laws, and the sorts of observation that could be trusted. Even so, their dispute-however wide-ranging and fundamental-lies in the region of intelligible disagreement that Davidson's argument leaves open.4
That said, there is something fishy about Kuhn's talk of meaning-shifts. In one way, it involves taking talk of meaning too seriously, and in another, not seriously enough.
The doctrine of incommensurability is underwritten by the view that the meaning of a term is entirely a function of the theory in which it occurs. Newton and Einstein both use the word 'mass'; but since their laws of motion are different-indeed, since Einstein recognizes two quantities, rest mass and relativistic mass, where Newton recognizes only one-they are not talking about the same thing. Or as Feyerabend (another devotee of incommensur ability) explains, the replacement of old principles by new entails 'the elimi nation of the old meanings'. 5 This is an overreaction. Because Newtonian mechanics is approximately correct for bodies moving slowly relative to the speed of light, there are various ways of relating Newton's theoretical vocabu lary to Einstein's. We might take Newton to be talking mostly about rest mass but believing falsely that it is the only sort of mass there is. Or we could take him to be referring indifferently to rest and relativistic mass, not realizing that any such distinction could be made. Provided we understand how the theories
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as a whole are related-particularly, the way in which one can be seen as approximately true of a restricted range of phenomena-it doesn't much matter. For such questions of interpretation, there is no definitely right way of proceeding. It depends on what similarities and differences we are interested in highlighting, which is a pedagogical matter, of no great theoretical import. This is the way in which Kuhn makes too much of the idea of meaning.
In another way, however, he doesn't look at the idea of meaning hard enough. Kuhn sees that a term's 'meaning' is partly determined by its inferen tial position in a wider range of assertional commitments. He also takes on board Sellars's point that the distinction between the 'observational' and the 'theoretical' is methodological rather than ontological. However, by stating this point in terms of the penetration of 'observation' by 'theory', he slides towards the view that nothing is really observational, or that observation exerts no independent check on our theoretical commitments. But no such conclusions follow from the epistemological and semantic views that Kuhn shares with Sellars. Observation reports are still causally tied to circumstances, and thus constitute a body of evidence whose contents we do not fully control. This much independence of observation from theory is not only consistent with but required by Kuhn's socialized Popperianism.
Not so sceptical
Kuhn's tendency to overstate his 'sceptical' conclusions is connected with a tendency, shared with Popper, not to distinguish between radical and non radical scepticism. It is one thing to say that, when theoretical choices have to be made, there is no algorithm that singles out a uniquely right answer; it is something else again to say that it never matters what choice we make, or that any choice is always as good as any other. The locally holistic character of theoretical inference does not support any such radical conclusion. An amus
ing example due to Thomas Nagel makes the point. Suppose I adopt the theory that eating lots of ice cream is the way to lose weight. It is true that in testing my theory by stepping on the bathroom scales I am taking for granted a lot of extra theoretical ideas, for example, the principles of mechanics that determine how the readings on the scales correspond to different weights. But it would be lunacy for me to conclude, in the face of the constantly rising numbers I encounter, that my diet must be affecting the laws of mechanics. One reason for this is that I have to take those same laws for granted in many other inquiries. Since they are effectively held fast, my weird dietary ideas are what have to go. It is not contextualism but an ill-thought-out form of radical holism that encourages relativism and irrationalism. It does so by encouraging us to see empirical inference as a largely unconstrained choice between com peting 'total views' in which anything and everything is up for grabs. Some thing like this form of holism may lie behind Kuhn's talk of 'different worlds'.
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The effects of failing to mark the radical/non-radical distinction can be compounded by playing back and forth between the considerations available to guide inference during the initial phases of a scientific revolution and those available when an alternative theory has emerged as a mature alternative to a received view. It may be that, in the early days, choices can only be made flying by the seat of one's pants. But they can become practically unavoidable as further evidence accumulates (though to accumulate that evidence, some investigators may have to make a seat-of-the-pants commitment) .
I think that these failures-making too much o f meaning and failing to mark the distinction between radical and non-radical scepticism-afflict Kuhn's critics too. For example, according to Hilary Putnam, we need to block a disastrous meta-induction, encouraged by the Kuhnian model of progress through revolutions. Past revolutionary changes in science suggest that 'all the theoretical entities postulated by one generation invariably "don't exist" from the standpoint of later science'. There is thus a serious chance that electrons will go the way of phlogiston. Indeed, the conclusion to be drawn seems to be that 'no theoretical term ever refers'.6 In theoretical science, we have no reason to suppose that we are ever talking about anything.
Putnam's hope is (or was) that the theory of reference-the theory of the word-object relation-is our best hope for responding to this sceptical view of theoretical discourse. But why suppose that a theory in the philosophy of language either could or should block this argument? (Hasn't the electron of the 1920s already gone the way of phlogiston?) How are we to rule out the .possibility of drastic theoretical change at some point in the future? Putnam wants something that is neither possible nor desirable: he wants philosophy to underwrite the truth of our current theories.
Putnam's problem looks dramatic at first sight but proves less than compel