Theory of Science


Discovery and rationality

In analyzing the natural sciences for philosophical purposes as historically developing enterprises, the question “What is it that makes the sciences rational?” is raised in a new form: do the intellectual procedures that scientists actually employ to investigate and explain natural phenomena have definite and objective intellectual merits that make their adoption rationally prudent, wise, and obligatory? In answering this question, philosophical opinion has tended to polarize in recent years toward two extreme positions: on the one hand, a formalist or positivist extreme, on the other, a romantic or irrationalist one. Given their mathematical inspiration and preoccupations, both the Viennese Empiricists and their successors in Britain and the United States have interpreted the rationality of scientific procedures as depending solely on the formal validity, or logicality, of scientific arguments. In their view, questions of rationality can be raised about the scientist’s work only at the final stage in his inquiries–i.e., when he sets out, as the final outcome of his work, the explicit explanatory arguments in support of his novel theories or interpretations–only then, they declare, will there be anything about science that is capable of being criticized in logical or philosophical terms. It is therefore a commonplace of recent Empiricist analysis in the philosophy of science that one must distinguish at the very outset between discovery and justification. The term discovery refers to all the stages in a scientific inquiry preceding the formulation of the new explanatory arguments that are its final outcome. The term justification refers, by contrast, to the demonstration that the formal validity or explanatory power of those arguments justifies the scientist in accepting their conclusions as scientifically validated or established. In this view, the rational concerns of the philosopher of science are restricted solely to this final phase of justification. All questions about the earlier stages–i.e., about discovery–are matters of mere psychology, not of serious philosophy. As one widely accepted epigram expresses it, “There is no logic of discovery”; and this distinction–given the equation of rationality within logicality–seemingly invalidates all questions about the rationality of the preliminary steps by which a scientist arrives at a discovery.At the opposite extreme, there are those, such as Michael Polanyi, a Hungarian-born scientist and philosopher, and Arthur Koestler, a novelist and journalist, who emphasize the parts played by intuition, guesswork, and chance in scientific investigation, citing these as evidence that theoretical achievement calls into play an intellectual creativity superior to mere rationality. According to this anti-Positivist argument, the modern scientist is a sleepwalker whose creative insight guides him to intellectual destinations that he could never clearly see or state beforehand: any excessive preoccupation with the rationality of scientific procedures, by contrast, springs from a pedestrian desire to clip the wings of imagination and to confine the scientist to stereotyped procedures, thus destroying the creative fertility of science. Rather than subjecting scientific intuition to the barren intellectual accountancy of the Positivists, the conclusion runs, one should embrace a romantic anti-rationalism. In each of these extreme cases, however, the initial equation of rationality with logicality demands closer examination. Certainly, the activity of investigation and discovery can be examined with advantage from a psychological point of view as it has been, in fact, by a French mathematician, Jacques Hadamard, as well as from a philosophical point of view. Yet the possibility of such psychological inquiries does not obviously prove, entirely by itself, that procedures of intellectual investigation in science and mathematics are essentially nonrational. Chance, for instance, may help to bring relevant material to a scientist’s attention. But chance–as has often been remarked–favours the prepared mind, and it is fair to ask how far the scientist acted rationally, after all, in picking out the items he did as being relevant to his particular problems. Similarly, in the case of creative intuition and the rest: once again, the man with the best trained mind can afford to give the freest rein to his intellectual imagination because he will be best qualified to appraise the rational context of his current problems and to recognize significant clues, promising new lines of analysis, or possible answers to his questions, as they come to mind. Neither denigrating the early phases of scientific inquiry as of merely psychological interest nor overpraising them as exercises of creative imagination disposes therefore of the philosophical problem that is here involved, viz., that of showing what makes certain procedures of investigation more rational than others.

To find a middle way between formalism and irrationalism, it is necessary to look more closely at the nature of the problems of scientific inquiry. If the improvement of scientific concepts and theories depends on the development of more powerful explanatory procedures, the philosophical analysis of discovery then requires that one show what is essentially involved in devising such procedures, testing them out, and determining the range of their application. This problem must be dealt with, furthermore, not by a formal analysis of the resulting arguments alone but first and foremost by establishing what tasks any novel explanatory procedure in science can be required to perform, what demands its performance can properly be asked to satisfy, and so what intellectual goals a scientist is expected to be aiming at in all the phases of his investigations. Posed in these alternative terms, the problem of scientific rationality becomes a problem of showing how conceptual changes in science result in the introduction of novel ideas, which are–in a phrase coined by Mach as early as 1910–“better adapted, both to the facts and to one another.” It is rational for older scientific theories to be displaced by newer ones that are functionally superior; and the task for philosophers of science is to demonstrate explicitly in what such functional adaptedness consists. At the present time, many younger philosophers of science are actively analyzing the nature of the problems of science in these terms. Significantly, most of these men have had their own primary training within the natural sciences proper rather than in formal logic or pure mathematics, for the task requires a much more detailed analysis of the processes of intellectual innovation than has been customary hitherto. In place of the simple dichotomy between discovery and justification, for instance, it calls for a subdivision of the innovation process into a more complex sequence of distinct stages; and at each stage both rational and causal considerations are relevant. Thus, at the initial stage in any inquiry, a scientist must decide which among all of the philosophically conceivable variants from the current repertory of explanatory methods are to be taken seriously at all; which, that is, are genuine possibilities. This preliminary sorting of initially plausible from implausible innovations must be dealt with–and dealt with in the most rational manner possible–long before any question of justification arises. This initial sorting procedure is one about which scientists themselves also speak cogently and eloquently. Far from deciding what novel suggestions are genuinely possible or plausible on a purely psychological basis or by the exercise of some mysterious, nonrational intuition, scientists will commonly explain their reasons for accepting one set of conceptual variants rather than another as deserving serious consideration.

At the same time, such microanalyses of scientific innovation must certainly leave room for causal as well as rational questions. During certain periods in the historical development of science, for instance, scientists have notoriously disregarded novel possibilities that later turned out to hold a key to the solution of crucial theoretical difficulties. Looking back at such periods, it is possible to reconstruct with care the rational considerations that might have been advanced at the time to explain this neglect; but even so, one is occasionally forced to conclude that the men involved were prejudiced against those possibilities by factors external to their sciences; e.g., by influences originating in the wider social, cultural, or political framework of their time. Thus, Newton was particularly afraid that his theory of material particles might be accused of supporting Epicureanism, whereas Darwin concealed his private speculations about the cerebral basis of mental activities because of public objections to Materialism. In analyzing the microstructure of scientific problem solving, it is necessary, accordingly, to resist any temptation to generalize prematurely.

Scientific investigators working in different fields, or at different times, apparently face theoretical difficulties of quite different kinds. One must therefore begin by studying the specific needs and tasks of each particular science, at one or another stage in its evolution, separately–seeking to recognize, in each individual case, the particular intellectual demands to be met by any new concept or theory if it is to be successful. Eventually, the accumulated results of specific microanalyses may bring the investigator to a point at which he can again afford to generalize about all of the assorted theoretical problems confronting, say, physics and about the broader intellectual demands to be met by successful theoretical changes in a variety of scientific situations. At the present stage, however, though philosophers of science still cannot afford to beg these questions, they are compelled to conduct their analyses in a more piecemeal way–building up their picture of scientific innovation and discovery by considering a wide range of sample cases and working their way only gradually toward a more comprehensive account of the problematics of the scientific enterprise.

Philosophies of the Branches of Knowledge: Philosophy of science: MOVEMENTS OF SCIENTIFIC THOUGHT” Britannica Online.
[Accessed 13 May 1998].



Validation and justification.

If this situation is true of the earlier stages in discovery, it is no less true in the case of justification itself. Here again, from 1920 on, the debate in the philosophy of science focussed predominantly on two sharply opposed positions, both of which appear in retrospect to be excessively narrow. On the one hand, Empiricist philosophers argued for a view that made prediction the crucial test of scientific validity; on the other hand, philosophers of a more Rationalist temperament saw coherence and scope as the crucial requirements. For Empiricists, the fundamental presupposition is that the facts justifying changes in scientific ideas are both intellectually prior to the theories that are, in due course, developed to explain them and also capable of being recognized independently and in advance of all theory construction. Given this presupposition, they regard prediction and validation as the crucial and distinctive steps in scientific procedure, arguing that, to establish the validity of any general scientific proposition, it is necessary to show that the theoretical generalization of which the validity is in question entails particular factual statements that are borne out by independent empirical observations. This validation process then involves two essential steps: (1) the formal step of inferring novel predictions from the theory and (2) the empirical step of comparing those predictions with the facts and so confirming the theory or proving it false.

On closer inspection, both steps in the received Empiricist procedure face serious difficulties, and these have lent strength–by reaction–to the alternative, constructivist position. As to step (1), there appears to be no objection to the idea of deducing particular factual predictions directly from theoretical hypotheses, so long as one accepts the Empiricist interpretation of laws of nature as universal empirical assertions on the same logical level as “All polar bears are white.” Once that interpretation is questioned, however, it is less clear that direct deductive inferences from theory to fact are always practicable. On the contrary, if theoretical laws and purely empirical reports are, in the nature of the case, framed in terms of distinct and diverse sets of concepts, no general procedure can be available for passing deductively from one to the other. For the theory will then be a reinterpretation of the facts, not a mere generalization from them. Similarly, with step (2), an empirical confrontation of theories and facts gives rise to a more complex range of choices than those implied by the Empiricist account. When faced with discrepancies between prediction and observation, scientists certainly have to modify their theoretical explanations; but this modification can normally be made in any of several alternative ways. For instance, the theoretical relevance of a particular observation may be questioned; or some alternative theoretical interpretation may be put forward; or further refinements may be made within the structure of the theory concerned–and all of this can be done before any question arises of a direct and necessary conflict between the discordant observation and the general theoretical doctrine under investigation.

The rival, constructivist position derives its attractions from such objections as these. This position follows lines of thought already sketched by the French theoretical physicist Pierre Duhem at the turn of the century. On this account, the essential test of a science is that it should provide coherent, consistent, and wide-ranging theoretical organizations. Empirical facts will then be recognized as scientifically relevant only to the extent that they exemplify these interpretations and make them more discriminating. Thus, no single factual observation can ever serve as a logically crucial experiment and confirm or refute any one specific doctrine conclusively, taken apart from a whole complex of theory and interpretation. What is at risk in any experiment or observation, therefore, is the whole body of the theory, together with the current conventions governing its empirical application; and the more comprehensive a theory is, the more are scientists free to vary the details of their specific applications of it, rather than to accept any single counter-example as a challenge to its general validity. (see also Index: experimentation) f these two philosophical approaches are reconsidered today against a broader and more historical background, however, they no longer appear to be either as exhaustive or as contradictory as they did in the 1920s and 1930s. By choosing suitable illustrations, of course, one can make each position highly attractive and plausible since, in one situation or another, the rational considerations that carry genuine weight in the actual justification of novel scientific theories include both predictive success and conceptual coherence. But the “Book of Nature,” as Galileo called it, is like Holy Scripture: it offers texts to suit all occasions and purposes. And, on second thought, it can be argued that both Empiricist and constructivist philosophers oversimplify the justification process in science and the criteria by which scientists judge the validity of novel concepts and theories.

Far from there being any single or simple test of validity, the question whether predictive success or coherence, simplicity, historical authenticity, or mechanical intelligibility is the key consideration–and in what sense of each ambiguous phrase–must be considered afresh from case to case, with an eye to the specific demands of each new scientific problem situation. Within the historically developing enterprise of science, intellectual problems arise of many different types, depending both upon the kinds of subject matter under investigation and upon the stage of development of the science concerned. In one science and at one stage, particular weight may attach to a single unexpectedly successful prediction: as when the wave theory of light led to the totally unexpected discovery that a perfectly circular obstacle placed in front of a point source of light produces a circular shadow having a bright spot at its centre. In another science or at another time, however, it may be neither practicable nor relevant to infer such specific predictions, and new theories and concepts may be validated by considerations of quite other kinds. Even within a single science such as physics, indeed, scientists are not faced at every stage by problems and judgments of a single, uniform type. Instead, the historical evolution of physics–down the centuries from Nicole Oresme, Galileo, and Newton to Maxwell, Rutherford, and Heisenberg–has generated an entire genealogy of varied problems; and the considerations bearing on the theoretical difficulties facing physicists at different stages have themselves changed, quite legitimately, along with the substantive concepts and theories of the science. So, within the more complex framework of a developing rational enterprise, the philosopher’s task is no longer to impose any single or simple criterion of intellectual choice upon scientific judgments of all kinds. Rather, his task is to recognize how the rational considerations and criteria of validity relevant to particular judgments vary with the theoretical problem situations that provide their historical contexts.

“Philosophies of the Branches of Knowledge: Philosophy of science: MOVEMENTS OF SCIENTIFIC THOUGHT: Validation and justification.” Britannica Online.
[Accessed 13 May 1998].


Unification, pluralism, and reductionism.As one notable illustration of the tug-of-war between logical and pragmatic issues in the philosophy of science, the “unity of science” movement may be cited. Under the vigorous leadership of Otto Neurath, a polymath sociologist and philosopher, this movement represented the high point in the ambitions of Viennese Positivism between World Wars I and II; for the general philosophical aims that motivated the search for a unified science are in striking contrast with the specific problem-solving considerations that lead working physicists to unify or integrate their theoretical concepts and explanatory procedures in actual scientific practice. Aside from the primary test of predictive success, the Positivists of the Vienna Circle also did allow–on their own terms–for the further theoretical virtues of coherence and comprehensiveness. Their logico-mathematical approach to the propositional structure of scientific theories, however, led them to interpret this demand for coherent and comprehensive theories in a formal sense. On their interpretation, a totally unified body of scientific ideas would be a comprehensive, quasi-Euclidean system of scientific theorems, based on a single set of general axioms, postulates, and primitive propositions and applicable to natural phenomena of all kinds. Given sufficiently all-embracing empirical generalizations as the starting points of such a unified science, it would then be possible, in their view, to deduce particular statements about all the phenomena covered by the varied special sciences unified within its axiomatic scope. Taking the symbolic logic of Russell and Whitehead as their formal core, philosophical advocates of the unity of science then set out to construct, on a single axiomatic pattern, a fully comprehensive account of nature capable of explaining (i.e., entailing) all natural phenomena whatsoever.

At first glance, this ambition seemed laudable and legitimate, but once again the Empiricist program subsequently encountered unforeseen entanglements. The reasons for this situation were not merely the discovery that the theoretical ideas employed within different branches of a science (e.g., of mathematical physics) are more resistant to conceptual integration than had originally been hoped (the task of constructing a self-consistent relativistic theory of quantum electrodynamics, for instance, is one that still defeats the physicists); but, what is worse, it has now become apparent that several well-founded and properly respected branches of scientific theory do not lend themselves to exposition in a formal mathematical manner at all. Any satisfactory theory of organic evolution, for instance, has an irreducibly historical dimension; and there is no possibility of putting historical zoology on the sort of predictive basis that Empiricists have demanded, still less of incorporating it into Neurath’s larger unified axiom system. Faced with this particular example, indeed, one distinguished Empiricist philosopher, Carl Hempel, has drawn a somewhat extreme conclusion, viz., that the theory of natural selection is not really an explanation of organic evolution at all–not even a bad one–but is merely an elaborate redescription of the historical episodes concerned. Yet this is simply a roundabout way of conceding that neither the historical problems nor the theoretical ambitions of evolutionary zoologists conform to the quasi-mathematical pattern that the Logical Empiricists have set out to impose on all of the natural sciences alike in the interests of a longer term axiomatic unification.

If, on the other hand, the demand for integration or unification is considered as a practical problem of methodology, it will then be found that the scientists are facing problems of a different and more pragmatic kind. The science of physiology poses an interesting example because, within this field, the problem of reductionismi.e., of whether all phenomena whatsoever can be reduced to physico-chemical terms alone–has repeatedly drawn active debate. Since the time of Antoine Lavoisier, who first explained correctly the process of combustion–i.e., since the late 18th century and even before–there has been a methodological division of opinion, involving, on the one hand, those chemists and physiologists who dreamed of equating physiological functions with chemical reactions and planned their program for biochemistry around that ambition and, on the other hand, those clinical scientists and functionally minded physiologists who questioned the legitimacy of this so-called physicalist program and insisted that physiological phenomena displayed certain features or aspects inexplicable in physio-chemical terms alone. The scientific issues in debate in this case have never been concerned with formal matters of axiomatization and logical integration alone: once again, they have involved substantive questions of interpretation. Correspondingly, the provisional resolution of this dispute, accomplished by Claude Bernard in the mid-19th century, was not arrived at by constructing a single, unified axiom system of biochemistry-cum-physiology. Rather, Bernard distinguished the proper questions and concerns of the two sciences and demonstrated the substantive character–and limits–of their mutual relevance. Regarded as specific, localizable processes within the main organs of the body, he argued, all physiological phenomena do, indeed, come within the scope of the same general physico-chemical laws and concepts as govern similar processes in inorganic systems. Within the special micro-environments of the body, however, those same general types of phenomena serve certain unique physiological functions, having no inorganic counterparts; and, to this extent, special problems and questions arise within physiology that cannot be exhaustively translated into the language of inorganic physics and chemistry. Though biochemistry and physiology in no sense conflict, there accordingly remains an essential plurality in the explanatory aims of the two sciences; and this plurality gives rise, in turn, to a corresponding plurality of methods and concepts.

Yet even this example does not yield conclusions from which one can safely generalize. Though in certain respects the explanatory aims of physiology and biochemistry will, most probably, always be distinct and separate, in other cases matters have gone the other way. When, in 1873, the Scottish physicist James Clerk Maxwell, for instance, integrated the previously independent sciences of electricity, magnetism, and optics into the unified physics of electromagnetism, there was no comparable division of opinion and no such methodological peace treaty was needed. In this case it remained possible, after Maxwell’s work as before, to distinguish between straightforwardly electrical, magnetic, and optical phenomena on the empirical level; but on a more general, theoretical level such distinctions lost their earlier significance, and it ceased to be necessary to keep the problems, methods, and explanatory categories of the three earlier sciences separated.

To sum up: in the methodological drive toward the unification of the sciences, as in the earlier phases of discovery and validation, the intellectual temptation to generalize prematurely exposes the philosopher to certain real dangers. In practice, the case for unifying the theories and concepts of two or more sciences has to be considered afresh in every instance, and it can rarely be decided in advance whether or not such a unification will achieve anything useful for the sciences. Instead, one has to analyze the practical demands of the current problems in the different fields and see how far those requirements can be met by developing a unified explanatory treatment for all of the special sciences in question. The integration of theoretical concepts achieved in the process will not consist solely in the formal running together of different propositional systems: more typically, it will require the development of a whole new pattern of theoretical interpretation. And, though it may be possible, in certain cases, to expound the resulting theory in axiomatic form, it must be established, in each case separately, whether or not this can be done. In this sense, conceptual and methodological unification represents a genuine movement in the development of scientific thought; but the logical form of the unified science towards which the philosopher is working is not something that he can lay down definitively before the event.

Philosophies of the Branches of Knowledge: Philosophy of science: MOVEMENTS OF SCIENTIFIC THOUGHT: Unification, pluralism, and reductionism.” Britannica Online.
[Accessed 13 May 1998].


Status of scientific propositions and concepts or entities.

The section of this article entitled Elements of scientific enterpriseexamined, first, the raw material (or elements) with which scientists have to work in developing their theories about the operations of the natural world and, second, the intellectual steps (or movements) by which they arrive at a scientific understanding of nature. By way of summary, it is appropriate to consider finally the main points of view about the intellectual status of the scientific concepts and doctrines embodying the understanding of nature that have emerged from the philosophical debate about science. Beginning with the epistemic status of theoretical propositions in science, it is well to consider the different claims that are made about the objectivity of their applications or their truth or both. Then, turning to the ontological status of the scientific concepts or entities, it is likewise necessary to consider the claims that are made about the objectivity of their reference or of their meaning or both. In either case, the purpose of a philosophical critique of science is to establish just how far the content and reference of scientific knowledge can be regarded as a true report about the actual structure and operations of nature and just how far they represent, on the contrary, intellectual constructs or artifacts in terms of which men have chanced, chosen, or found it desirable to organize their thoughts about the structure and operations of nature.

Starting with the epistemic status of scientific theories, three main views can be distinguished: At one extreme is a strict Realist position, which underscores the factual basis of all scientific knowledge and emphasizes the logical contingency that this basis implies for all substantive propositions in science. In this view, all but the most purely formal statements in science make assertions about how the world of nature is constituted and operates in fact–as contrasted with all of those alternative states of affairs that are clearly intelligible and so possible but which turn out not to be true of the actual world. Seen from this Realist standpoint, every proposition in science, from the most particular observational report to the most general theoretical principle, simply reports a more or less comprehensive empirical set of facts about nature and aspires to be an accurate, objective mirror of the more or less universal facts about which it speaks. At the opposite extreme, there is a strict conventionalist position, which underscores the constructive role of the scientist’s own theory articulation and emphasizes the logical necessity that is thereby built into the resulting conceptual structure. In this view, all but the most purely observational statements in science reflect the patterns by which the scientist shapes his conceptual picture of the world of nature–the patterns in terms of which all states of affairs clearly conceivable on the basis of current ideas have necessarily to be formulated. Seen from this conventionalist standpoint, theoretical thermodynamics, say, determines the character of all possible worlds consistent with the principles of energy conservation and entropy (or randomness) increase: a world to which thermodynamics is not applicable will then be not so much factually false as inconceivable in present terms. Finally, a wide range of intermediate views seeks to evade the central opposition between Realists and conventionalists. One representative view of this kind, first made popular by Mach toward the end of the 19th century, invoked Kant’s attack on things-in-themselves, viewing the attack as providing grounds for dismissing all debates about reality and objectivity as inescapably barren and empty. In its most developed form, this so-called operationalist position encourages the philosopher to regard theoretical propositions in science as meaningful only insofar as scientific practice includes specific operations–either manual measuring operations, or computational pencil-and-paper operations–in terms of which those propositions are given operational meaning. Nothing is then to be read into scientific knowledge beyond its operational meaning; in particular, scientists are not to be understood as claiming or disclaiming anything about the reality or conventionality of the states of affairs that they report. The idea of nature as a thing-in-itself is thus eliminated, as being an intellectual superstition and an obstacle to better scientific understanding, which survives from an earlier metaphysical era.

Three main views should here be distinguished. The central question is, now, whether the nouns and noun phrases used as technical terms in the theoretical propositions of science rely for meaning on any claim that they refer to objective, external entities; and current approaches to this question parallel existing views about the epistemological issues, viz., whether the propositions themselves rely for their truth on a claim to be mirroring or reporting objective, external facts. Here, too, the Realist interprets all of the chief technical terms of scientific theory as the names of objective entities existing in nature independently of all human theories and interpretations. In this view, entropy, say–a measure of the increase in randomness that every total system undergoes–is a genuine, objective magnitude that has, at all times, played a crucial part in the operations of nature even though physicists have only recently had the wit to discover it; and it just happens, correspondingly, to be the case–in those parts of the cosmos that can be observed–that the total entropy of an isolated system nowhere decreases. The instrumentalist, for his part, regards all theoretical notions such as entropy as intellectual fictions or artifacts created by the scientist’s own theory construction and quite distinct from the natural world of objects, systems, and phenomena that scientific theories have to explain. No doubt, scientific theory and the external reality of nature do come into contact on the everyday or empirical level of tables and chairs, rocks and flowers. Given the intellectual tasks of scientific theorizing, however, the resulting concepts are essentially abstract; and any grasping after real entities, as the objective external reference of the theoretical terms, reflects a plain misunderstanding of this theoretical enterprise. Meanwhile, the phenomenalist repeats, in the case of the technical terms of science, the same agnostic criticism as that offered by the operationalist in the case of its theoretical propositions. In this view, it is simply a meaningless waste of time for scientists to debate the existence of enduring theoretical entities, regarded as external, objective things-in-themselves; just as it is similarly wasteful for them to interpret scientific theories as making, or denying, similar claims about the existence of objective, external states of affairs. Instead, the terms and concepts of science are all to be understood as the product of so many logical, or semantic, operations or constructions, and questions about their real existence are to be swept aside as damaging metaphysical superstitions.

“Philosophies of the Branches of Knowledge: Philosophy of science: PHILOSOPHICAL STATUS OF SCIENTIFIC THEORY” Britannica Online.
[Accessed 13 May 1998].


Philosophical analysis and scientific practice

The arguments about these rival ontological and epistemological views cannot be safely left or judged without first looking more closely at the complex relationship between the general analytical interests of philosophers and the more specific intellectual concerns of working scientists themselves. For the degree to which each view about the reality of scientific entities and facts can carry conviction depends substantially on what branches of science are at issue. As the focus of philosophical attention has shifted historically from one scientific terrain to another, so, too, have the relative degrees of plausibility of these rival positions varied. Since the 1920s, for instance, there has been a marked revival of philosophical discussion among scientists working in several specialized fields–particularly, among physicists concerned with the structure and development of quantum mechanics. In epistemic terms, the statistical character of quantum-mechanical explanations has prompted some fundamental questions about the status and limitations of human knowledge. Clearly, the extent and accuracy of human knowledge about nature are limited by the modes of operation of scientific instruments. Is it not also possible, however, that the significance of this statistical character lies at a deeper level? Perhaps the relevant objective relationships and states of affairs in nature itself are governed intrinsically by a merely probabilistic causality and so are essentially indeterminate. Or is there a point to be reached on the microphysical level at which any such distinction between subjective human knowledge and the objective state of affairs has finally broken down? The ontal implications of quantum mechanics have been as puzzling as the epistemic. Is an electron, say, a discrete particle that just happens to elude man’s exact observation; is it an essentially blurred wave bundle having no precise dynamical characteristics; is it a concentration of probability, a mere theoretical symbol, or what? Or must one set all these ontological questions aside as lacking any significance for physics and as standing in the way of the physicist’s proper task, that of extending the direct explanatory power of quantum-mechanical explanation itself?

Elsewhere, the philosophical debate about science has taken on other specific forms. Just as in Aristotle’s natural philosophy the metaphysical controversy about Ideas and essences was reflected in Aristotle’s own methodological approach to biology and to the study of the natural relations and classification of organisms, so once again 20th-century reappraisals of traditional taxonomy–in the light of evolution theory, genetics, and population dynamics–have been an occasion for renewed philosophical debate. As a result, earlier disagreements about natural and artificial classifications have been reformulated and have generated a new dispute, about the possibility of basing taxonomy on a mathematical science of phenetics–in which the defining properties of different species, genera, etc. are all given quantitative numbers or measures–and so harnessing the technical resources of modern computers to its purposes. Similarly, in the psychology of perception and related fields, the extension of understanding in recent years at last has permitted the framing of authentically empirical questions about perception and cognition, which lend themselves to direct investigation instead of being restricted to general a priori speculations. The result has been a theoretical debate, the final outcome of which will have profound effects on both philosophical epistemology and natural science. In areas of this debate where even Mach was content to pose entirely general questions, in the philosophical tradition of David Hume, about the role of sense impressions as the raw material of all cognition and perception whatsoever, it is now clear that many preliminary differences and complexities must be unravelled before one can hope to recognize the truly operative questions in this field. Far from all modes of knowledge and perception conforming to a single common pattern, man’s sensory and practical dealings with the world call into play a variety of perceptual systems of which the operations justify no simple epistemological formula about impressions and ideas, sense-data and logical constructions, or intuitions and schemata. Thus, at the present time, the investigations of some physiologists, psychologists, and cyberneticists are bringing man’s sensory and cognitive activities within the scope of natural science while at the same time preserving a feeling for the more general philosophical problems and insights of such philosophers as Locke and Leibniz, Hume and Kant, Helmholtz and Mach.

At this point, the alliance between science and philosophy is simply carrying over into fields of science that are areas of methodological perplexity today the same interactions that were fruitful in earlier centuries within sciences having methods by now well understood. These interactions are unlikely to vindicate finally any one of the rival positions in the philosophy of science, whether ontological (Realist, instrumentalist, or phenomenalist) or epistemological (Realist, conventionalist, or operationalist). Probably such a vindication was, in any event, too much to expect. For in all the different special sciences–both natural and social–historical development eventually brings the investigator to a point at which he is ready to operate with a variety of technical terms or entities having very different logical characters and functions and at which his most general theoretical propositions or principles display corresponding differences in their logical status and implications. So long as philosophical discussion is confined within the limits of an artificial, ideal language or propositional system, it is possible, perhaps, to continue posing purely abstract, general dilemmas about, say, theoretical entities or confirmation theory. But the bearing of such formal dilemmas on the actual content of contemporary scientific thought is becoming increasingly unclear. In debating the ontal status of theoretical entities, for instance, the question must at some stage be faced whether that phrase is intended to cover such notions as gene or pi-meson, species or cold front, momentum or superego, social class or economic market. (Certainly, not all of these terms have identical characters and functions.) In debating the epistemic status of scientific theories, likewise, it must be made clear whether one has in mind, say, the mathematical schema of quantum-mechanical field theory, the populational analysis of natural selection, the microstructures and mechanisms of molecular biology, the developmental sequences of cognitive psychology, the labour theory of economic value, the general regularities of terrestrial meteorology, or what. (Once again, not all of these theories have identical kinds of status or implications.)

Philosophical doctrines and approaches that carry great conviction when applied to the theories and ideas of one science may–not surprisingly–lose all of their plausibility when extended to other fields. Thus, an Empiricist analysis may apply quite straightforwardly to meteorology, yet entirely misrepresent the structure and implications of electromagnetic theory; while, in return, a Neo-Kantian account of theoretical physics may lack any direct relevance, say, to ideas about animal behaviour. Today as in classical Athens, analytical clarification in the philosophy of science goes, in this respect, hand in hand with methodological refinements in the sciences themselves. In retrospect, the methodological insights of Aristotle the marine biologist and of Plato the theoretical astrophysicist can be seen to have been complementary, rather than incompatible. Similarly, today, the philosopher must look at rival positions in the philosophy of science not merely as contradictory answers to technical questions within philosophy itself but equally as complementary contributions to the methodological improvement of theoretical understanding over the whole varied range of different scientific fields.

“Philosophies of the Branches of Knowledge: Philosophy of science: PHILOSOPHICAL STATUS OF SCIENTIFIC THEORY: Philosophical analysis and scientific practice.” Britannica Online.
[Accessed 13 May 1998].



This survey has been concerned, almost exclusively, with philosophical problems and arguments about the sciences regarded as sources of theoretical knowledge. In pitting Realism against instrumentalism, mechanistic ideas against organicist ones, divine knowledge against human fallibility, or Platonic Ideas against Aristotelian essences, the philosopher is in each case concerned with the intellectual status, implications, and validity of certain general scientific concepts, methods, or entities. To confine oneself entirely to these intellectual aspects, however, would mean accepting a total abstraction of theory from practice and of scientific ideas from their behavioral expression. Thus, along with the present-day shift of emphasis from the physical to the human and social sciences, one finds that all such abstract approaches are coming once again under criticism, as over-intellectualizing the nature and implications of science. Some of these attacks come from the neo-Marxist direction and reflect a traditional Marxian insistence on the unity of theory and action. (It was not for nothing that Lenin picked on Ernst Mach as a special target for scorn.) Analogous criticisms, however, are also coming from men with very different intellectual loyalties–e.g., from the urban sociologist Lewis Mumford and from many contemporary Existentialists.

In conclusion, therefore, a concise discussion is here given of some of the views about the relations between science and the rest of culture; i.e., about the relevance of scientific knowledge to other spheres of experience and concern and, conversely, about the significance of broader, practical considerations for man’s understanding of scientific theory itself. The variety of these views has always been very great. Their exponents have ranged all the way from those who, like the energeticist Wilhelm Ostwald and the evolutionist Julian Huxley–both of whom rooted ethics in nature–present scientific ideas and procedures as rational panaceas for intellectual and practical problems of all kinds to those who, like Pierre Duhem and Carl von Weizsäcker, physicist and philosopher of nature, both of whom are theists, deliberately limit the claims of science so as to preserve a freedom of manoeuvre for ethics, for example, or theology. At each stage, most advocates of extreme claims for science have been ontological Realists; and, in strengthening their ontal and epistemic claims, they have also staked a claim to overriding intellectual priority on behalf of scientific knowledge, in contrast to other forms of experience. Similarly, those who would restrict the broader cultural claims of science have tended to be phenomenalists; and, in weakening their philosophical claims, they have also attempted to limit the authority of science to its own intellectual concerns as narrowly defined.

Whatever one’s general philosophical position with respect to the reality of scientific knowledge and entities may be, however, there are other more practical questions to be faced, questions about the specific implications of different scientific ideas and beliefs for parallel fields of human action and experience. On this point, one particular theme unites a wide range of radical critics of science, including both Lewis Mumford, U.S. social critic, and the Existentialists. Just as the Christian Dane Søren Kierkegaard, an early and seminal figure of Existentialism, condemned Kant’s universalized system of ethics for ignoring the individuality of actual ethical problems and decisions, so today there is a widespread reaction against any tendency to treat social or practical decisions as technical matters, which can be left to the judgment of scientific or technological experts. The general methods of technology may, indeed, represent practical applications of the theoretical understanding arrived at by science; but all individual decisions about putting those general techniques to use–e.g., in constructing an airport or power station–must be made not by appealing to any general formula or rule of thumb but by balancing a whole range of diverse considerations–economic and aesthetic, environmental and human, as well as merely technical.

According to another contemporary critique, the theoretical points of view adopted in natural science are general and abstract, but the practical demands of sociopolitical action and, a fortiori, of individual action, are concrete and particular; and, by itself, this contrast places an immediate restriction on the existential relevance of scientific ideas and engineering techniques. Such scholars as Thomas Huxley, a versatile scientist and defender of evolution, or Wilhelm Ostwald, a pioneer in electrochemistry, who viewed reality as essentially energy, might argue in general, abstract terms for interpreting ethical principles in evolutionary or thermodynamical terms if they pleased (so the critics continue); but such abstract speculative arguments have no bearing on the actual tasks of ethical decision and action. Here again, every ethical choice involves a unique constellation of considerations and demands; and this problem cannot be dealt with by appealing to any universal rule but must be appraised on an individual basis, as and when it arises.


Others take a more positive approach toward the contribution of science to an understanding of human values. Without necessarily claiming to transform ethics itself into a “science,” they at any rate argue that the personal attitudes needed for effective work in science–adventurous skepticism and critical open-mindedness–have a wider relevance also to human conduct and social affairs. Supposing only that social and political discussion were conducted in this same tentative and critical spirit (they claim), its typical and deplorable passion and confusion could be replaced by the more rational consideration of the means required in order to achieve explicitly stated ends. While specific scientific ideas and doctrines may not be enough to direct social and political action by themselves, the scientific attitude may, nonetheless, have a profound significance for social policy and individual ethics alike. This contrast, between existentially minded critics of the claim that science is all-embracing and socially minded believers in the scientific attitude, may be epitomized by referring to contemporary discussions about the social significance of science itself.

On the one hand, there has recently been a revival of explicitly anti-scientific views, which had been more or less dormant since the time of Blake, Johann Wolfgang von Goethe, and their successors in the Romantic movement. Supporters of this anti-science position point to the central role of military technology in the financial support of 20th-century scientific research and dismiss the average scientist’s plea that he is not responsible for the uses to which his ethically neutral discoveries are put, as pallid and insincere. On the contrary (they argue), there is a long-standing and unholy alliance linking the collective institutions of the scientific and technological professions to the economic, industrial, and political powers that be. Faced with the fruits of this historical union (they conclude), it is time that scientists acknowledged their social responsibilities; and, failing better institutional controls, the outcome of this moral self-scrutiny may well prove to be a moratorium on further scientific research. Perhaps man already knows too much for his own good and needs to digest the significance of his existing stock of knowledge much further before adding to it and so widening yet again the gulf between theoretical knowledge and practical wisdom.

On the other hand, there are those who recognize science as playing a crucial role in modern society, but who go on to draw the opposite conclusion. Rather than putting a stop to science (these men would argue), its scope should be broadened; that is, scholars should be studying and understanding better the manner in which science serves as an element in the larger social order–perhaps by developing more adequate analyses of the social structure or perhaps by a large-scale extension of the methods of operations research. Aside from anything else (they point out), a moratorium on science is as impracticable as a moratorium on sin. It could be enforced only if political unanimity prevailed to an unimaginable degree among scientists. In the absence of such enforcement, liberal-minded countries will merely put themselves at a needless disadvantage–both economic and military–as compared with totalitarian states. Instead of pursuing this will-o’-the-wisp, scholars should put more effort into the task of understanding both the social preconditions of effective scientific development and the economic and political priorities involved in the practical application of scientific research.

As compared with the controversies of earlier centuries, the debate between science and religion is curiously muted today. There seems little room nowadays for the theological passions that engulfed the discussion of Copernicus’ new planetary theory, James Hutton’s history of the Earth, or Darwin’s theory of natural selection; and one would hesitate to speak any longer, as so many of our forefathers did, of warfare between science and religion as unavoidable. It is true that a few partisan writers can still find it a perplexing problem to decide such issues as whether the existence of life on other worlds would require a re-enactment there of the Christian fall and redemption or can insist–conversely–that the results of astronautical exploration refute any religious belief that God is an Old Man up in the sky. For most people, however, such questions have so far lost their earlier bite that they appear, by now, quite naïve. What is the reason for this change? In earlier times, the term cosmology embraced not only the structure of the astronomical cosmos and the origins of the human species but also the religious significance of man’s place in nature. Contemporary theologians, by contast, see physics and biology as having much less bearing on man’s religious attitudes and preoccupations than their predecessors had supposed that they had. As a result, men’s earlier ambition to construct a single, comprehensive world view, embracing the essential truths of both science and religion, no longer plays the active part in intellectual life that it formerly did. The only branches of science still capable of provoking vigorous theological debate, even now, are the human, rather than the natural sciences. The implications of Freudian psychology for the doctrine of grace and the use of psychedelic drugs for inducing quasi-mystical experiences are topics for live discussion today, in a way that evolution, astrophysics, and historical geology no longer are.

This change of focus has been accompanied by a change in ideas about the intrinsic limits of science. It was formerly assumed that the boundaries between science and other aspects of human experience could be defined by marking off certain types of subject matter as essentially closed to scientific investigation. To one generation, the heart of this forbidden territory was the mind; to another, it was life; to a third, the creation. In this view, something in the essential nature of mental or vital activities, or in the origins of the present order of nature, made it impossible to treat these as phenomena open to study and explanation by the rational methods and intellectual procedures available to science. In fact, this view always had defects, from both the scientific and the theological points of view. To scientists, it seemed to impose an arbitrary restriction on their sphere of operations and so acted as a standing challenge and irritation. For theologians, it had the disadvantage of placing the essential claims of religion, so to speak, on a sandbank, where they risked being submerged in time by the rising tide of scientific knowledge. So, by tacit consent, the essential limits of science are now defined in quite different terms. These limits are now identified by recognizing that the character of scientific procedures themselves places restrictions on the relevance of their results. A scholar may choose to study whatever objects, systems, or processes he may please, but only certain of the questions that he asks about them will be answerable in the general, theoretical terms characteristic of science. This change of approach may not have made the substantive problem–that of delimiting the frontiers of science exactly at all points–very much easier to deal with than it was before, but it has one genuine merit: it respects the crucial fact, to which attention has been drawn at several points in this present survey, that the distinctive features of science lie not in the types of object and event to which the scientist has access but in the intellectual procedures that his investigations employ and so in the kinds of problem that lend themselves to a scientific solution.


“Philosophies of the Branches of Knowledge: Philosophy of science: INTERRELATIONSHIPS OF SCIENCE AND CULTURE” Britannica Online.
[Accessed 13 May 1998].