What is the status of scientific truth-claims? Can they purport to hold good for all time across vastly differing contexts of language, culture, and society? That is to say: is science in the business of providing valid explanations of physical objects and events whose nature remains constant despite such deep-laid shifts of cultural perspective? Or is it not rather the case—as currently argued by relativists, pragmatists, and ‘strong’ sociologists of knowledge—that those contexts provide the only means of understanding why science has taken such diverse forms (and come up with such a range of competing ‘truths’) throughout its history to date?footnote¹

These questions are of interest not only to philosophers and historians of science but also, increasingly, to cultural and critical theorists influenced by the widespread ‘linguistic turn’ across various disciplines of thought.footnote² They are often linked with the issue of ontological relativity, that is, the argument—deriving principally from W.V. Quine’s famous essay ‘Two Dogmas of Empiricism’—that there exist as many ways of describing or explaining some given phenomenon as there exist ontological schemes or systems for redistributing predicates over the entire range of sentences held true at any particular time.footnote³ On this holistic account there is no means of drawing a firm, categorical line between synthetic and analytic propositions, or matters of factual (contingent) truth which might always be subject to revision in the light of further evidence, and on the other hand those so-called logical ‘laws of thought’ whose truth is assumed to be a matter of a priori necessity and hence—by definition valid—for all possible contexts of enquiry.footnote⁴ And with the collapse of this distinction, so Quine argues, we must also relinquish the idea that philosophy of science might yet come up with an adequate method for linking observation-sentences to theories (or vice versa) through a clear-cut set of logical procedures. For in a holist perspective those sentences can possess meaning—that is to say, be assigned determinate truth-values—only as a function of their role within the entire existing ‘fabric’ or ‘web’ of beliefs, or the entire set of truth-claims (‘empirical’ and ‘logical’ alike) that currently happen to command widespread assent. Which is really to say that there are no such determinate truth-values, since theories are always at some point ‘underdetermined’ by the best evidence to hand, while that evidence is always ‘theory-laden’—or committed to some prior ontological scheme—right down to the level of its basic data as given in first-hand observation-sentences. Thus for Quine it follows that one must apply a principle of strict ontological parity as between (for instance) Homer’s gods, centaurs, numbers, set-theoretical classes, and brick houses on Elm Street. Any preference in the matter—and Quine admits readily that he has a whole range of such preferences—must in the end come down to one’s particular choice of ontological scheme.footnote⁵

There are many other sources of this relativist trend in contemporary philosophy of science. They include Thomas Kuhn’s highly influential account of the way that science alternates between periods of ‘normal’ and ‘revolutionary’ activity, the former characterized by broad agreement on what counts as a proper (constructive and disciplined) approach to certain well-defined problems, the latter by a sense of impending crisis—and an absence of agreement on even the most basic principles—which heralds the transition to a new epoch.footnote⁶ Here as with Quine it is taken for granted that all the components of a given scientific ‘paradigm’—from observation-sentences to high-level theories—are intelligible only in terms of the prevailing consensus, or according to the overall framework of beliefs that provides its own (strictly immanent) criteria of truth, progress, theoretical consistency, evidential warrant and so forth. But it then becomes difficult—if not impossible—to explain how we could ever gain insight into scientific world-views other than our own, or again, how historians of science could ever claim to understand the reasons (i.e. the scientific grounds) for some decisive paradigm-shift, as distinct from the various short-term cultural, social or historical factors that may have played some part in bringing them about. Hence Quine’s recourse to the idea of ‘radical translation’ as a means of (purportedly) bridging this otherwise insuperable gulf between different observation-languages or ontological schemes.footnote⁷ Hence also the difficulties that Kuhn confronted in his 1969 Postscript to The Structure of Scientific Revolutions when responding to his critics on the issue of relativism and its self-disabling consequences. For it is far from clear that these difficulties are in any way resolved by his Quinean (radical-empiricist) line in the face of such strong counter-arguments.footnote⁸

The problem is yet more acute with those kinds of ultra-relativist position adopted by proponents of the present-day ‘linguistic turn’ in its full-fledged (postmodern) guise. Thus it is sometimes claimed—as for instance by Richard Rorty—that our best model for interpreting the process of scientific paradigm-change is what happens when poets and novelists come up with striking new ‘metaphors we can live by’, or again, when strong-revisionist literary critics interpret such metaphors after their own fashion.footnote⁹ Then again there are those—the late Paul Feyerabend chief among them—who espouse an anarchistic philosophy of science which rejects all appeals to truth, logic, reason, consistency, experimental proof, and the like.footnote¹⁰ On this view the idea of scientific ‘progress’ is nothing more than a piece of bogus mythology, one that takes hold through our myopically equating ‘truth’ with what currently counts as such according to this or that (self-authorized) ‘expert’ community. Much better, Feyerabend thinks, to have done with this misplaced reverence for science and instead take account of the various factors—social, political, psychological, careerist and so forth—which have always played a decisive role in the history of scientific thought. For we can then see how mixed were the motives (and often how random or opportunist the methods) which gave rise to some so-called ‘discovery’ or ‘advance’ that is nowadays treated as a text-book example of its kind. And this will bring two great benefits, as Feyerabend sees it. First, it will help to demythologize science—to remove some of its false prestige—and thereby open it up to criticism from other (i.e. non-‘expert’ but socially and ethically more responsible) quarters. Second, it will encourage scientists to become more adventurous in framing risky conjectures or in pursuing novel and heterodox lines of thought.

There are various explanations that might be adduced for the current appeal of such ideas. One is the widely-held view that philosophy of science can no longer have recourse to any version of the logical positivist (or logical empiricist) distinction between truths-of-observation on the one hand and self-evident (tautologous) truths of reason on the other.footnote¹¹ There are similar problems—so it is argued—with the appeal to deductive-nomological (or covering-law) theories, those that would seek to account for observational data by bringing them under some higher-level (metalinguistic) order of logical entailment-relations.footnote¹² For here again the way is open for sceptics like Quine to argue that any such distinction will always be drawn according to some preferred ontological scheme, some languageor culture-specific set of descriptive or explanatory priorities. One alternative that has enjoyed wide favour, not least among practising scientists, is Karl Popper’s hypothetico-deductive account whereby the measure of a theory’s claim to genuine scientific status is not so much its truth as established by the best current methods of experimental testing but its openness to falsification by those same methods.footnote¹³ This account has the signal advantage of explaining how a great many scientific theories that once enjoyed widespread credence should eventually have turned out mistaken, or—as with Newton’s conceptions of absolute space and time—‘true’ only relative to a certain restricted domain. It thus meets the criticism of those, like Feyerabend, who would exploit such evidence to the point of denying that notions of truth have any role to play in the history and philosophy of science.

But there are difficulties with Popper’s position, among them its reliance on under-specified criteria of what should count as a decisive falsification (or as grounds for rejecting some candidate hypothesis) in any given case. In other words, the methodology of ‘conjecture and refutation’—as Popper describes it—amounts to just a minor inverted variation on the positivist or logical-empiricist theme. Moreover, so his critics maintain, Popper has made illicit use of this dubious methodology in order to attack what he sees as the pseudo-scientific pretensions of Marxism and other such ‘historicist’ trends in the sociological, interpretive, or humanistic disciplines.footnote¹⁴ For if there is one type of argument that always draws fire from the present-day cultural relativists it is the idea that science should enjoy any privileged truth-telling status, any method or set of validity-conditions that would place it apart from those other (on its own terms) less rigorous or rationally accountable modes of knowledge. Such is the distinction standardly drawn between the ‘context of discovery’ for scientific truth-claims and the ‘context of justification’ wherein those claims are subject to testing by the best available criteria of experimental warrant, theoretical consistency, causal-explanatory yield, and so forth.footnote¹⁵ But this distinction is rejected by those who maintain—whether on grounds of ‘ontological relativity’ or in pursuit of the so-called ‘strong programme’ in sociology of knowledge—that truth is just a product of localized beliefs whose origin should be sought in their cultural context or in the socio-biographical history (the professional interests, careerist motives, childhood experiences, religious convictions, and so on) of the scientists who held them.footnote¹⁶

The poet Auden nicely epitomized this genre in its vulgar form: ‘A penny life will give you all the facts’. More sophisticated—but no less sophistical—variants would include Feyerabend’s well-known claim that in the case of Galileo versus Cardinal Bellarmine and the Church authorities it wasn’t so much an issue of truth—i.e. of the heliocentric as against the geocentric hypotheses—but simply a question of who had the better argument on rhetorical, social, or political grounds.footnote¹⁷ Thus if Bellarmine sought to promote the interests of communal stability and peace, while Galileo can be shown to have fudged certain details (observational data) in order to preserve his theory, then the Church comes off rather better on balance and—so Feyerabend advises—should even now stick to its doctrinal position and not lean over to accommodate the present-day scientific orthodoxy.footnote¹⁸ Other versions of this argument (if rarely pushed to such a provocative extreme) are often to be found in the current literature on history and sociology of science. What they all have in common is the nominalist persuasion that ‘truth’ is just a term honorifically attached to those items of belief that have managed to prevail—by whatever strategic or rhetorical means—in this contest for the high ground of scientific ‘knowledge’ and ‘progress’. Other sources include the ‘social construction of reality’ thesis (taken up in philosophy of science by writers like Barry Barnes and David Bloor);footnote¹⁹ the sceptical ‘archaeology’ of knowledge essayed across a wide range of disciplines by Michel Foucault;footnote²⁰ and the argument of postmodernist thinkers such as Jean-François Lyotard that science is just one amongst a range of incommensurable language-games (cognitive, ethical, historical, political) and no longer exerts any privileged claim in respect of knowledge or truth.footnote²¹