Objectivity of knowledge has been a key issue in the course of the entire history of philosophical thought. In our time, too, it remains a touchstone of the true attitude of one or another philosophical school to science revealing the extent of its influence on social and practical life. Those philosophers who show interest in this problem have always been aware, vaguely or keenly, that knowledge which cannot be regarded as objective is powerless or useless, and that the practices relying on such pseudo-knowledge are adventurist and even harmful. Failing to meet the requirements of objectivity, they are bound to become arbitrary.

Philosophical schools do not always focus their attention on the problem of objectivity, let alone placing it in the foreground. Wittingly or unwittingly, it is often overshadowed by other issues, seemingly more concrete and, at first sight, more pressing. Yet it always underlies all controversies over the place and role of metaphysics, i.e. over the subject-matter of philosophy, and has a direct bearing on such problems as the relation of sensory experience to theory, induction to deduction, truth to error, etc. Therefore the problem of the objectivity of knowledge sometimes becomes, as it were, a concentrate of many issues pertaining to different aspects of the theory of knowledge.

It would not be correct to say that this problem has been treated separately from all other problems of the methodology of science, such as causality, determinism, laws of development, etc. Yet its solution has always been determined primarily by the answer to the question if reality exists outside and independently of man. Any answer to this, be it positive, negative or fifty-fifty, and even abstention from any answer at all, is in itself a sufficiently clear indication of the philosopher’s views on the content and nature of knowledge. Attempts to elude the issue have never helped to make the philosophers’ and scientists’ life easier—on the contrary, the muddle has always grown worse.

In its attempts to reject all unscientific, metaphysical problems, including the problem of the independent existence of objective reality and such “absolutes” as matter, substance, space, causality and others, positivism has proved to be no more fortunate than other philosophical schools. However, it would be interesting and instructive to trace the impact of the objectivity problem on positivist philosophy in general, and on its specific concepts and notions in particular. This question deserves special attention if only for the fact that numerous gullible authors take in all good faith the rejection by positivism of the problem of the existence of objective reality as metaphysical, whereas others, aware of the latent contradiction in the views of the positivist writers, suspect them of a crafty intention to conceal the true meaning of their philosophy and its subjectivism. As a matter of fact, neither of these views can be accepted without serious reservations. The issue is much more complicated than is implied by the proposed explanations.

There is yet another aspect to the problem of the objectivity of knowledge in positivist philosophy—the understanding of its true attitude to this problem provides a key to understanding the modern criticism of the positivist programme by “critical rationalism”, “scientific realism”, “scientific materialism”, etc.

Being always opposed, as it was, to the discussion of the so-called metaphysical problems and, in particular, refusing to investigate the relation of knowledge to the objective world and bother about the origin of scientific knowledge and what lies behind this knowledge, positivism could not afford to discard completely the principle of the objectivity of knowledge. Declaring against this principle would be tantamount to opposing the fundamental scientific tradition, in fact, the entire history of science which has always held that objectivity was its chief goal and basic trait distinguishing it from other forms of knowledge and intellectual culture.

Positivism has regarded traditional philosophy to be metaphysical first and foremost because it postulates the existence of transcendental reality different from and independent of the sensuous world. The question of the existence of the physical world independent of sensory experience has always been viewed by positivism from Comte to Reichenbach as a pseudo-problem at best. Refusing to discuss the origin of scientific knowledge, positivism has also regarded as metaphysical the question of its development not only from the historical, but also from the logical angle. Both these negative premises of positivist philosophy have led to a number of dramatic conclusions. For instance, Mach not only discards the “absolutes” of Newton’s mechanics, for which he had good reason, but also declares himself against the atomic theory. Accepting the theory of relativity and quantum mechanics, Carnap and Reichenbach interpret them merely as logical devices to systematise and harmonise sensory experience.

In the notes to his article “The Elimination of Metaphysics through Logical Analysis of Language” (1957) Carnap comes out against idealism as a metaphysical tendency. At the same time, expressing his attitude to metaphysics he writes: “This term is used for the field of alleged knowledge of the essence of things which transcends the realm of empirically founded, inductive science. Metaphysics in this sense includes systems like those of Fichte, Schelling, Hegel, Bergson, Heidegger.” [1] Carnap is evidently not aware of the fact that this criticism reaches far beyond his target and hits the theoretical pillars of all modern science, as well as its material foundation. Reichenbach, on his part, ignores the real dialectical unity of the corpuscular and wave properties of matter which was not known to classical physics and which is considered in Bohr’s concept of complementarity developed and elaborated, among others, by Vladimir Fock and his disciples. In his philosophical discourse on quantum mechanics Reichenbach makes certain assumptions regarding the terms “particle” and “wave” which, in his opinion, are “neither true nor false” and proposes a theory of equivalent descriptions according to which both the corpuscular and wave interpretations are admissible under certain conditions as “they say the same thing, merely using different languages”. [2]

The independent existence of objects made no serious problem for the researchers in classical science. First, their attention was mainly focused on the external side of the physical world and science was only building up strength to penetrate the hidden mechanisms of phenomena and processes, the structure of physical bodies, the earth’s bowels, the intricate heredity carriers and the laws of cosmic processes. Second, the notions expressing the properties of objects and phenomena under observation differed but little . from current everyday concepts. Third, the distorting influence of the researcher on objects and phenomena under investigation was incommensurate, even in terms of energy alone, with real processes in nature and could not therefore affect to any appreciable degree the course or direction of these processes. Finally, progress in scientific cognition was very slow and scientific concepts and theories were not subject to rapid change, at least on a historical scale. Knowledge accumulated and grew in scope without any serious breakdowns. Revolutionary changes in science were regarded by scientists themselves as something quite out of the ordinary.

Positivism as a philosophical teaching was a typical product of its time, though it was not destined to have a long life. As physics and other sciences were passing on from macroscopic objects familiar to man from his everyday experience to the inner structure of matter, the problem of objectivity was acquiring essentially new scope and dimensions. Scientific notions were more departing from the ideal of sensual certitude, observability. Particularly heavy was the blow delivered on the principle of sensual certitude by the discovery of electron and other microparticles at the end of the 19th century.

The crisis in physics at the turn of the century was regarded as crisis of all former scientific ideals, including the ideal of objective knowledge and, consequently, as a crisis of materialism. The fact that objects under investigation could be observed no longer was used by positivist philosophy not for revising its mistaken views, but for confusing the issue, namely, for rejecting the idea of any reality beyond the limits of sensory experience. Incidentally, it is precisely this philosophy clinging to the obsolete ideals of empirical science that bears responsibility for the survival of the dogmas of metaphysical materialism in natural sciences till the end of the 19th century—the dogmas which had been discredited and buried by dialectical materialism half a century earlier.

If objective reality is only what is observable, the task and the function of theory consist merely in finding as yet unknown observable and measurable objects proceeding from the available sensory experience and taking into account the body of mathematics. In this case theory does not play any independent role and its function is confined to purely logical analysis leading a scientist from one sensory experience to another.

The obvious implication of this approach is that a non-classical theory should be free from any new notions, i.e. notions having any new physical meaning, new objective content. A physical theory is merely a new logical means to systematise the observable.

Quantum mechanics, however, proved to be not only far removed from the ideals of positivism—it was a direct challenge to it, despite some temporary rapprochement between them regarding the principles of causality and objectivity which ended in a complete alienation, evidently final. The positivists regarded quantum mechanics as an expression of experience or its elements connected by formal logical means. By contrast, Bohr’s aim was rather to find out the conditions making experience possible, i.e. its necessary premises. The so-called Copenhagen interpretation is often associated with the assertion that “the non-existent cannot be observable”. Its essence, however, will be more accurately summed up in this statement: the observable is definitely existent, the nonobservable allows of certain suppositions.

The purpose of research in classical physics was to establish definite phenomena taking place in space and time and to investigate laws determining the course of processes. A problem was considered solved if the researcher succeeded in proving that a process did take place in space and time. The method whereby the process had been cognised, the observations which had made it possible to ascertain its existence experimentally were absolutely immaterial. In the quantum theory the physicist is faced with an entirely different situation. The very fact that the mathematical scheme of quantum mechanics is not a graphic representation of processes taking place in space and time shows that it can only permit calculating the probability of one or another result of an experiment based on the experimental knowledge of the previous state of the atom system, in so far as the latter has not been subjected to any other disturbances except those needed by the experimentalists themselves. Even a most complete set of experimental conditions cannot give more than a mere probability of the result expected in the next experiment on the system. To the positivists it was a sure sign that any objectivity of the processes in interest was entirely out of the question. Each observation led to a certain discrete change of the mathematical values characterising the atomic process and, consequently, to a discrete change of the physical phenomenon itself. In contrast to the classical theory, where the method of observation was immaterial for the process under investigation, in the quantum theory the disturbance produced by each observation of atom phenomena plays a decisive role. Further, since any observation can only be summed up in probability statements as regards the results of later observations, the account of the essentially uncontrollable disturbance component must become, according to Bohr, a decisive factor in constructing a quantum theory free from contradictions.

As distinct from positivism in general or, at least, from its most radical (or most naive) versions, Bohr did not consider sensory data to be elementary entities. What he called phenomena could only be defined within a broader context of “reality”. This reality as the context of experience could be set by concepts performing the role of definite conditions or premises of classical physics. Bohr usually meant two such conditions: spatial-time description and causality which were only compatible within the classical model of events. In his opinion, the discovery of the quantum of action had led to a break between them and to the adoption of the principle of complementarity of descriptions.

Things being as they were, Bohr and a number of his followers made an attempt to combine the object of observations, the measuring apparatus and the observer into a single quantum-mechanical system and thus to eliminate uncertainty. In his speech on receiving a Nobel prize, Werner Heisenberg said that classical physics was the kind of aspiration for the knowledge of nature in which scientists strove to make conclusions on objective processes proceeding in fact from their sensations and refusing to take into account the influences of all observations on the object being observed. Quantum mechanics, on the contrary, obtained the possibility of considering atomic processes by partly refusing to objectivise them and describe in terms of space and time.

Despite the controversies lasting many years this interpretation known as the “Copenhagen approach” has not yet completely lost its grip on the minds of philosophers and physicists many of whom are still inclined to think that by breaking with the traditions of classical science quantum mechanics has opened up a new epoch. “Quantum mechanics,” writes, for instance, J. A. Wheeler, “has led us to take seriously and explore the ... view that the observer is as essential to the creation of the universe as the universe is to the creation of the observer... Unless the blind dice of mutation and natural selection lead to life and consciousness and observership at some point down the road, the universe could not have come into being in the first place; ... there would be nothing rather than something.” [3] Hence, quantum mechanics provides a new point of reference for understanding all events in the universe, including its emergence in the form which engendered our life itself. Reality, according to Wheeler, can no longer be regarded as independent of the observer.

Eugene Wigner, too, is inclined to share the opinion that quantum mechanics deals with nothing else but “measurements” or “observations”. He maintains that the equations of movement both in classical and quantum mechanics do not describe reality but are merely instruments to calculate the probability of certain results of observations. His opinion is in full conformity with the positivist views that the observation becomes fulfilled when the observer’s consciousness is brought into play and that not a single system has any definite measurement attributes of its own—they appear only as a result of the very process of measurement or simultaneously with it. In this connection Wigner writes: “It is the entering of an impression into our consciousness which alters the wave function because it modifies our appraisal of the probabilities for different impressions which we expect to receive in the future. It is at this point that the consciousness enters the theory unavoidably and unalterably. If one speaks in terms of the wave function, its changes are coupled with the entering of impressions into our consciousness.” [4] There is nothing surprising, according to Wigner, in that idealism provides the most relevant representation of the world. Even if it were possible to exclude the observer (or sensations) from the analysis of a quantum-mechanical situation, it would be necessary, in Wigner’s opinion, to project him mentally.

Indeed, observation and measurement are important requisites for the construction of quantum mechanics. The admission of this fact, however, leaves open the question of the relations between the components of this unity— the system, the instrument and the observer. Wigner’s method reduces the first two to the last one. The independent existence of physical objects is called in question. To be sure, Wigner does not aver that consciousness creates its images in absolute vacuum or that physical theories are products of immaterial elements. His viewpoint, rather, consists in that scientific research is limited to the sphere of actually existing, i.e. observable, events. Wigner does not simply repeat the arguments of Machist philosophy but goes further making the object more and more dependent on observation. This view leads, in fact, to the elimination of the positivist concept of system-instrument unity in favour of the logical primacy of the observer.

As a result, reality becomes the world of experience or the “empirical world”. Modern physicist S. W. Hawking goes even as far as asserting the existence of some impenetrable “curtain” which completely shuts out everything that lies behind it. In his opinion, gravitational collapse sets an obvious barrier to scientific cognition which can hardly be expected to be overcome even in the distant future. The thing is that the inner state of the “black hole” is, according to theoretical calculation, unobservable in principle. Hence, gravitation provides an example of uncertainty regarding the existence of real objects, which is even of a higher order than the uncertainty in quantum mechanics. Recalling Einstein’s winged words “God does not play dice” in his well-known controversy with Bohr, the author even attempts to strengthen Bohr’s arguments. In his opinion, “God not only plays dice, he sometimes throws the dice where they cannot be seen.” [5]

Another threat to the objectivity of scientific knowledge comes from the probability

interpretation of the so-called Ψ-function. According to Bohr, the wave and corpuscular theories of microparticles need not necessarily be contradictory in reality despite their conceptual incompatibility. Both theories are equally important for the physical reality, each covering a definite type of situations, and consequently, are complementary. Proceeding from this viewpoint, some physicists and philosophers came to the conclusion that the Ψ-function is a wave function representing the density of probability and, consequently, is merely a mental projection of theory on a physical situation.

In point of fact, nothing but the form of mathematical equations makes it possible to treat a particle as a certain “density of probability” which can represent it in an experiment. The Ψfunction provides but a partial description of physical reality and, besides, merges the object and the subject into a single whole. Though, according to Heisenberg, we can separate them temporarily in different specific situations, they can never be completely detached from each other. [6]

Erwin Schrodinger contends that one can hardly assert the existence of waves in nature if probability is their characteristic feature. In his opinion, one can only speak of the probability of an event if one believes that it does occur now and then. If the probability function does not describe any physical reality in an experiment it definitely does not give any information on what takes place “between two experiments”.

As we see, some of the above arguments boil down to the assertion that what is not observable cannot be accepted by science. Others emphasise the fact that wave is the only form of quantum movement in space, which is attested to by such physical phenomena as interference, diffraction and others. Since waves represent nothing but probability, doubt is cast on the existence of particles in the period between the experiments ascertaining their presence.

It should be noted that the above viewpoint leaves out of account two important circumstances. First, any experimental set is a macrosystem. Analysing the results of experiments, a physicist cannot but proceed from certain laws governing physical phenomena. As a rule, he does not have to resort to probability functions. Second, the idea of the inseparable unity of the subject and the object reflects the simple fact that dynamic and spatial parameters cannot be defined simultaneously in a single experiment. Indeed, certainty can only be attained within definite limits. This fact, however, gives no grounds at all for a conclusion that the unity of the object and the subject is inseparable in general. Besides, even if particles do appear in the course of an experiment only, as is the case with excited vacuum (virtual particles), probability as a state is no less objective than actuality. From the viewpoint of the positivist interpretation of physical reality the very idea of such objectivity is bound to look preposterous indeed.

The real obstacle confronting the experimentalist and preventing him from accurately defining the parameters of a moving particle consists at present in the objective and glaring contradiction between the absense of any system capable of emanating or absorbing less than one quantum of energy, on the one hand, and the inevitability of the exchange of energy, however negligible, between the instrument and the object in any measurement or experiment, on the other. As regards the microworld, where one quantum of action and the object under measurement are commensurate, any process of measurement will cause a substantial change in the state of the object. All that does not prove, however, that the existence of the object in microphysics is completely dependent on the subject.

It stands to reason that the observability of an object as such does not provide a solid ground for scientific cognition. The progress of theoretical research and particularly quantum mechanics and the theory of relativity, have revealed the inadequacy and limitations of observation as a method of cognition to the positivists themselves. The development of theoretical science has enhanced the danger of solipsism which was evident even to the Machists way back in the late 19th century. The very fact that quantum mechanics and the theory of relativity appear to be equally meaningful to different people irrespective of their nationality and ideological affiliation has called for a considerable extension of the notion of objectivity. From the methodological viewpoint, the philosophers of science have begun to attach ever growing significance to Hume’s old idea that the focus of attention should be shifted from the observation of individual phenomena to the regular repetition of events, their regular concomitance or sequence. A separate experiment can neither confirm, nor refute a hypothesis—it takes a whole series or succession of observations. Philipp Frank, a representative of late logical positivism, wrote: “A single experiment can only refute a ‘theory’ if we mean by ‘theory’ a system of specific statements with no allowance for modification. But what is actually called a ’theory’ in science is never such a system... Therefore, no crucial experiment can refute any such theories.” [7] From this it follows that one of the main requirements to an experiment is its reproducibility at different times and in different parts of the universe.

What is the purpose of this methodological principle leading to the denial of the decisive role of experiments in science? Its aim is to replace the criterion of observability by the criterion of inter subjective verification of knowledge. As a result, objectivity becomes equivalent to intersubjectivity. Solipsism can be avoided (without resorting, like Berkeley, to God) by recognising at least the existence of other people. But this is not all, of course. It must also be postulated that people are alike everywhere, consequently, the reality constructed by them will also be similar everywhere. Contrary to common sense which accepts only one physical world, the emphasis on the subject who is the architect of reality leads to a tempting idea that different scientific theories and, consequently, their authors represent different worlds which they themselves construct. To avoid absolute relativism ensuing from this concept, it is necessary to show additionally how one experience can be compared with another, i.e. to solve the problem of their mutual correction. Naturally enough, subjective experience may fail to tally with what is regarded true by common consent. Let us consider at least one of the answers to this question proposed by Max Born which is sufficiently typical of all attempts of the positivists to find a way out of a difficult situation without forfeiting their main dogmas.

Expounding his views, Born describes a conversation with his cousin who asked him a puzzling question way back in his school years: “What do you mean exactly when you call this leaf, here, green or the sky, there, blue?” Dissatisfied with Born’s reference to the impressions of other people who all saw green and blue like he did, the cousin said: “There are colourblind people who see the colours differently; some of them, for example, cannot distinguish red and green.” [8]

The answer to this question appeared to be far from simple and the question itself was evidently not at all as superfluous as it had seemed at first to Born, if he deemed it necessary to return to it time and again in his declining years. Moreover, Born admitted that he had found the meaning of this question even more profound after he had got acquainted with the classical answers to it given by Kant, Russell, Mach, and Hume. Assessing the positivist doctrine alongside those of other philosophical schools he was to some degree familiar with, Born wrote: “In the most radical interpretation this theory means a denial of the existence of an external world, or at least the negation of its knowability. In practical life a follower of this doctrine would hardly behave as if there were no external world.” [9]

Born, however, does not accept the materialist view either. In his opinion, dialectical materialism has so broadened the concept of matter that its initial meaning has been completely lost and the concept itself has become too far removed from concrete problems of physics. The existence of the real, objective, knowable world, according to Born, has turned into a sanctified creed.

Born offers his own solution to the problem of objectivity of knowledge. In his opinion, the impossibility to prove the objective existence of green leaves and the blue sky is rooted in the attempt to reach an agreement on a single sensory impression. Such a task, according to Born, is nonsensical. Objective knowledge can only be reached by obtaining the perceptions of two communicable impressions which lend themselves to intersubjective verification. The equality or inequality of such impressions can already be ascertained quite definitely. Born lays special emphasis on the communicability of impressions. One person cannot give an adequate description of his sensations which he experiences when looking at a green leaf, but two persons together can come to an agreement regarding the colour of the leaf they observe.

Objectivity is thus reduced to the equality of impressions. An important means of comparing impressions is a symbol, i.e. a visual or a sound signal the exact form of which is not important— what matters is the information conveyed by this symbol. One and the same set of data can be represented by different signals. Symbols performing the function of data carriers during intercourse between individuals are of decisive importance in attaining objective knowledge.

The process of cognition is visualised by Born as follows. A child assimilates language as the totality of symbols and learns to correlate them with one another. It is worth noting that Born does not speak of the correlation between symbols and the objective world, but of the correlation between different symbols with definite meanings. Hence, given the ability to manipulate symbols, the measurement of heat intensity can be presented as the process of correlation of the sensation of heat with a geometrical value (the height of the mercury column in a thermometer). Learning provides man with a dictionary and enables him to correlate sensations through the agency of thermometer readings, i.e. to correlate his sensations with other people’s sensations. Similarly, chemistry teaches people to correlate different substances with a combination of symbols denoting elementary basic components (atoms). By correlating atomic weights with the symbols of elements one can learn the corresponding molecular weights, whereas the correlation of valency with the symbols of atoms makes it possible to forecast the results of chemical reactions.

Such correspondence of sense data (perceptions and the corresponding symbols) is established, according to Born, in all spheres of experience. Born notes the existence and coincidence of structures which are identified with the help of the sense organs and indicates that the corresponding impressions can be passed from one individual to another. He is even inclined to call these structures after Kant “things-in-themselves”. Physical formulae and systems of equations need not necessarily symbolise what is known from experience and what can be visualised. Yet Born is convinced that all these formulae are deduced from experience through abstraction and a continuous process of experimental test.

For the sake of objectivity, the scientists should describe the essence of their abstract formulae in the plain language, using self-evident notions. Yet modern science, according to Born, cannot avoid subjectivity, no matter how hard the scientists may try to do so. On the whole, Born’s interpretation of the complementarity principle falls in line with the principles of the Copenhagen school: a scientist is free to choose the experimental apparatus which is to be used in his experiment. However, the selection of the apparatus determines the picture of reality. “Thus a subjective trend,” writes Born, “is reintroduced into physics and cannot be eliminated. Another loss of objectivity is due to the fact that the theory makes only probability predictions, which produce graded expectations.” [10]

As we see, Born in fact substitutes the process of tuition and learning for the cognition of reality. He proceeds from an already existing system of knowledge which enables the individual experience of every man to be harmonised. This approach implies that individual experiences are identical and therefore do not need any comparison, elaboration and correction of their content. It is quite sufficient to correlate the symbols denoting one or another totality of impressions. Such a model has in fact nothing in common with the real process of scientific cognition which aims first and foremost at investigating new, unknown phenomena, but not at harmonising and systematising individual experiences with the help of an arbitrarily selected aggregate of symbols described by Born.

Of course, the communicative aspect of scientific cognition is in itself an interesting philosophical problem, but it should not overshadow the essence of scientific cognition. Criticising Mach for his attempts to reduce the world to sense perceptions and the scientific theory to a means for establishing logical links between sense perceptions, Born is in fact very close to positivism in his understanding of the process of cognition. The world lying “beyond phenomena” indeed remains for Born something like the Kantian “thing-in-itself” which is not amenable to any determination. As a result, the problems of truth, of the certitude of knowledge and of the means for improving incomplete and inaccurate knowledge become superfluous. No reason whatsoever is given for the identity of our perceptions of reality, except for the reference to the selected system of symbols and to an agreement on their meanings—such identity is the more strange as the subjective perceptions of different people vary to a considerable extent and as there are no similar people with equal abilities for perception, equal personal experiences, equal interests and equal stocks of knowledge, let alone many important personal qualities.

The investigation of these problems has long since transcended the bounds of physical science, though the problems themselves have not become any easier for that reason. On the contrary in such fields as chemistry, biology, the psychology of public opinion, and others where the possibilities for observation are limited, it has proved even more difficult to explain how subjective knowledge can be turned into objective knowledge, verifiable and applicable for practical purposes as it is. To save the principle of objectivity in these fields on the basis of empiricism, the philosophy of science had but one way out only—to sacrifice its traditional phenomenalist approach in favour of physicalism. This did not mean, however, a complete break with traditions, since the philosophical thinking of the positivists has always been characteristic of a peculiar symbiosis of both the phenomenalist and the physicalist approaches. Whereas the philosophers advocating phenomenalist analysis contended that sensory experience was the basis of knowledge from the epistemological viewpoint and that the statements expressing such experience formed the language of all meaningful propositions, the physicalists believed that the foundation of all knowledge was the observation of material things and that the statements of observation made the core of the language which was used for expressing the meaningful propositions of cognitive value. Carnap, for one, represented both these tendencies in different periods of his life. Siding up first with the phenomenological branch of positivism, he became later one of the most persistent and, perhaps, most profound expounders of the second branch too. As a result of the evolution of his views, Carnap became, willy-nilly, an instrument for a considerable deflation of the initial claims of physicalism, though the latter has not lost its ground completely till nowadays.

For later-time Carnap, the foundation of knowledge is not irrefutable statements, as he believed earlier, but statements which underlie any scientific investigation and provide a psychological basis of cognition not only for a scientist, but also for any individual in general. It is these initial statements that can be connected intersubjectively with other statements and therefore make the objective foundation of knowledge. Carnap’s radical physicalism boils down to the assertion that all meaningful statements can be connected in one way or another with a statement of the type: “the temperature in this place varies within 5 to 10° C.” According to Carnap, the statements of such sciences as biology, chemistry, geology, etc. can be reduced to physical notions because the type of determinism prevailing in these sciences can be reduced to physical determinism. “All laws of nature,” he writes, “including those which hold for organisms, human beings, and human societies, are logical consequences of the physical laws, i.e. of those laws, which are needed for the explanation of inorganic processes.” [11] For instance, the notion of impregnation can be interpreted in terms of merger of sperm and ovum accompanied by some redistribution of elements. Similarly, psychological knowledge, in Carnap’s opinion, can be reduced to physical knowledge. Thus, a statement to the effect that somebody has been very angry at 10 a.m. today can be translated without any detriment to the scientific value of this statement into the language of physics by stating that the person’s breathing and pulse have quickened, the muscles have strained, etc. True, Carnap concedes that this reduction may perhaps fail to provide a clear idea of the laws underlying impregnation in the first case, and the emotional process, in the second. Making this concession, Carnap does not concern himself about the nature of the impregnation process or the individual’s inner world. He views the problem from the angle of verbal descriptions only. If such descriptions prove to be impossible for some reason or other, there can be no question of attaining intersubjectivity, i.e. the objectivity of biological and psychological phenomena as they are understood by different scientists.

In turn, the correctness of the initial statements of observation is made by Carnap contingent on the extent of agreement between the sense data of different observers. If the sense data of each of the observers are consistent with the interpretation of the indications of a certain apparatus designed to fulfil a given task, it means that the initial statements required to form a scientific proposition have passed the test for viability.

True, intersubjective observability has certain advantages over the phenomenologic language from the standpoint of the development of scientific knowledge. Nevertheless, one can hardly take seriously the attempt, to construct all sciences, psychology and social disciplines including, on the basis of physics, arid expect all theoretical concepts and laws to be derived from physical concepts and laws. Being aware of the weakness of his position, Carnap later proposed several modified variants of the physicalist programme limiting it, for instance, to the reduction of all descriptive terms in the languages of different sciences to terms denoting sensuously perceived properties of things. In his opinion, the class of observable material predicates can provide a reliable basis for the reduction of all statements and for language integrity. For instance, the ability “to be dissolved in water” is revealed and confirmed by the observation of the fact of dissolution. It was a significant moderation of Carnap’s initial stand, as the sphere of observable empirical and dispositional predicates is markedly broader than the .sphere of terms expressing our sense data in purely physical parameters. Finally, in one of his latest works entitled Philosophical Foundations of Physics Carnap beats a further retreat and confines himself to a mere recommendation of a very general character, an admonition rather than an injunction, advising the scientists to base their language on the language of physics wherever possible. This is all that remained of his formerly uncompromising physicalism.

Of certain interest in this context is also the position of Ernst Nagel, one of the latest and sufficiently radical adherents of the physicalist principle of reductibility. Like all other philosophers siding with the modern philosophy of science and upholding some essential traditions of positivism, Nagel sees the meaningfulness of empirical statements in their connection with direct observation, considering logical links between them chiefly formal or linguistic. In his opinion, a theory can only be meaningful if its statements relate to potentially observable things and do not run counter to its principles. He denies meaningfulness to those statements which have no empirical confirmation. According to Nagel, the data of experience, observation statements and logical links play each their special role in the process of cognition.

Nagel maintains that any attempt to base the knowledge of physical facts on sensory data is doomed to failure. If the whole edifice of science were built on direct sensory experience, knowledge would never go beyond its limits.

Nagel contends that our knowledge includes objective facts, but not simple sensory data or some of their complexes localised in the sphere of sensory experience. It is only after investigation and by no means before it that we can claim the possession of sensory data. Investigation alone enables us to assert that the earth is round and that President Roosevelt remained in office longer than his predecessors.

In Nagel’s opinion, the objectivity of our knowledge does not lead to metaphysical realism. He supports the view of some other physicalists that the doctrine whereby all statements on directly observable objects can be translated into the so-called physicalist language should be replaced by semantic realism in which non-observable objects are represented by a system of nomological statements.

According to Nagel, in proposing the reduction of one theory to another we implicitly proceed from the assumption that there exist some methods to demonstrate the deducibility of one theory from another. “In reductions of the sort so far mentioned,” Nagel writes, “the laws of the secondary science employ no descriptive terms that are not also used with approximately the same meanings in the primary science. Reductions of this type can therefore be regarded as establishing deductive relations between two sets of statements that employ a homogeneous vocabulary.” [12] Nagel admits that the secondary science sometimes includes notions which are absent from the primary science.

Understandably, positivist physicalism is directed against openly idealistic concepts which not only fail to provide adequate answers to acute theoretical questions, but in every way hamper the development of modern science. The biologists, for instance, can hardly be encouraged in their investigations by philosophical doctrines explaining all the processes in living organisms by the operation of mysterious immaterial agents such as entelechy or the vital force which do not yield to any rational determination or even description. Central to all these doctrines from Emil Dubois-Reymond’s time till nowadays has been the idea of blessed ignorance—ignoramus et ignorabimus. A prominent biologist Konrad Lorenz says in his book The Reverse of the Mirror that this view not only acts as a brake on scientific progress, but is also one of the gravest errors having a dire consequence—a doubt about the reality of the external world. [13] Lorenz deplores the belatedness of his enlightenment and notes that the practical problems of medicine and natural science have made him an opponent of idealism. This materialist tendency of modern science causes many biologists to turn their eyes to philosophical materialism.

Confessions of this kind are not exceptions with prominent representatives of modern biology. Another well-known biologist, Francisco Ayala, makes this significant statement: “The goal of science is the systematic organization of knowledge about the universe on the basis of explanatory principles that are genuinely testable.” [14] The reappraisal of values is characteristic not only of modern biology. Idealism is being subjected to devastating criticism in many works on the physiology of higher nervous activity, on neuropsychology, neurophysiology, etc.

Contrary to idealistic theories of knowledge the latest investigations in biology and psychology provide convincing evidence that human thinking is not entirely autonomous. Viewed from both the psychological and epistemological angles, it represents the ability of highly organised living systems to reflect, i.e. to cognise, the external world and themselves.

How does this materialistic tendency reveal itself in the modern “philosophy of science”?

Several trends are in evidence here. The beaten track for the adherents of this philosophy is to restrict the problem of objectivity to the problem of observation and accumulation of empirical data. Since the observation of intimate biological processes is identified by many scientists with the analysis of their physical manifestations, their materialism not infrequently borders on physicalism. When it comes to the analysis of new phenomena, particularly in biology, psychology and sociology, the researchers seek in the first place to trace them to the operation of physical or chemical mechanisms. Naturally enough, it is the only way to “transfer” many biological, psychological, social, demographic and other processes to the sphere of the observable. Carnap writes that the physical language is universal. This is the thesis of physicalism. If the physical language on the grounds of its universality were adopted as the system language of science, all science would become physics. The various domains of science would become parts of unified science. According to Carnap, the laws of psychology are special cases of physical laws holding in inorganic physics as well. Identifying all materialism with its mechanistic trend, Carnap believes that the materialist system corresponds to the viewpoint of the empirical sciences, since in this system all concepts are reduced to the physical. [15]

It is common knowledge that molecular genetics and molecular biology owe their

achievements to modern physics and chemistry. Physico-chemical investigations have enabled scientists to make the greatest discoveries in modern genetics—to reveal the molecular structure of DNA (desoxyribonucleic acid) as the carrier of genetic information and to define the role of nucleic acids, their molecular and sub-molecular structures, in heredity. These epoch-making achievements of molecular genetics and molecular biology have given a new impetus to the mechanistic doctrine and mechanistic reductionism according to which all life processes and properties of living organisms, as well as the origin and evolution of living matter can be explained with the help of physico-chemical investigations of microstructures and microprocesses in living organisms.

The history of science shows that the ideas stimulating scientific investigations in their initial stage do not always prove beneficial for the subsequent progress of science. The inception of molecular biology was indeed marked by the influence of the physicalist paradigm. Noting this fact, E. N. Lightfoot, however, seeks to perpetuate it: in his opinion, the investigations in molecular biology have been based on the view that living organisms are subjected to the same laws as inanimate objects and can be denoted by terms corresponding to these laws. Now, says Ayer, he holds the same view, though on a higher level of complexity and comprehension.

This mechanistic approach has been expressed in a most uncompromising form by the discoverers of the molecular structure of DNA, John Watson and Francis Crick. In one of his lectures in 1966, Crick declared that the ultimate goal of the modern development of biology was explanation of all biological phenomena on the basis of achievements in physical and chemical sciences. In his opinion, there were very good reasons for that. The revolution in physics in the mid-1920s provided a solid theoretical basis for chemistry and for the corresponding departments of physics. According to Crick, it would not be presumptuous to assert that the quantum theory and the available empirical knowledge in chemistry provide at present a no less reliable foundation for the construction of biological science.

Crick’s reference to quantum rather than to classical mechanics is indicative of a new trend in the modern doctrine of physicalism. Nevertheless, the essence of this doctrine does not change— as before, it represents a tendency to express biological phenomena, processes and laws in the physico-chemical language.

Taking exception to “organicism” and “holism” one of the representatives of this trend Jacques Monod writes: “Some philosophical schools (all of them being consciously or unconsciously under Hegel’s influence) are known to contest the significance of analytical approach to such complex systems as living beings. According to these schools (organicists or holists) which rise from ashes like Phoenix with every new generation, the analytical approach qualified as reductionist has always been sterile since it tends to reduce, purely and simply, the properties of extremely complex organisations to a mechanical aggregate of the properties of their parts. Harmful and useless is any argument with holists which testifies to nothing but their utter ignorance regarding the scientific method and the essential part played in it by analysis.” [16]

Monod also rejects the general theory of systems [17] and any “dialectical description” [18] of living organisms. According to Monod, the cell is indeed a machine which defies any “dialectical” description. In its essence it is not Hegelian, but Cartesian. According to Kenneth Schaffner, regarded to be a typical representative of modern mechanistic reductionism and physicalism, the discovery of Watson and Crick also contributes to a general development towards a complete chemical explanation of biological organisms and processes and substantiates the view that “genetics, and other biological sciences, are reduced to physics and chemistry”. [19]

It is noteworthy, however, that while repeating the familiar propositions of radical mechanistic reductionism in relation to living organisms and biological science, Schaffner is forced to make reservations after each of his statements thereby confirming the irreducibility of biological phenomena to physico-chemical ones. Schaffner’s views are apparently anti-vitalistic and anti-idealistic. He cannot but admit qualitative distinctions between the living organisms and the dead nature, yet he persists in his mechanistic reductionism as he sees no alternative to it except for the idealistic doctrine which he does not accept.

The crisis of biological chemism and mechanistic reductionism in modern biology is at the same time the crisis of neopositivistic physicalism, the “logico-empirical analysis of science”, whose representatives from Otto Neurath, Rudolf Carnap and Percy W. Bridgeman to Rudolf B. Braithwaite, M. Brodbeck and Carl G. Hempel have invariably pursued one and the same aim, viz. to reduce the biological to the physical.

Until recently the neopositivistic “philosophy of science” was predominantly the “philosophy of physics” and made no serious attempts to apply its logico-empirical analysis to biology. However, the gap has started filling up. The most important “contribution” in this direction appears to be Michael Ruse’s book The Philosophy of Biology, which is remarkable, for one, in that it convincingly shows the difficulties facing the positivists in their attempts to apply the logicoempirical analysis of science, i.e. physical reductionism, to biology. Ruse is out to prove that such application is possible. He stresses, for instance, that “there are now no theoretical barriers in the way of a Nagelian-type reduction and that there are obvious signposts about how this should be done, as that such a reduction has been rigorously accomplished... It is only after this development that the physico-chemical and the biological came into harmony, opening the way for a reduction, or at least, for a possible reduction.” [20]

Ruse obviously strives for a consistent implementation of the logico-empiricist, i.e. positivist, approach to the present problems of biology and to the future of biological science. At the same time he is aware of the appeal of organicism to the biologists and admits that many branches of biological science, such as systematics and palaeontology seek to develop their own theories, genuinely biological, without resorting to molecular-biological, i.e. essentially physical, explanations. He regards such trends as transient phenomena and expresses a hope that biology would ultimately take the course of reductionism and translate its theories into the language of physics and chemistry. In his opinion, the existing state of affairs can only be explained by the stubborn reluctance of prominent modern biologists to join the new school of molecularbiological reductionism.

In positivist philosophy empiricism as the criterion of the objectivity of knowledge is inseparably linked with reductionism. Epistemological reductionism tending to reduce all scientific knowledge to its empirical basis was supplemented by theoretical reductionism which revealed itself in persistent attempts to translate all the wealth of accumulated knowledge together with its theoretical explanations in the language of physics. From the viewpoint of logic, this transition is understandable: the laws of physics permit experimental checks of theoretical propositions making them testable. Hence, theoretical reductionism leads to and finds its logical expression in physicalism. The language used in the description of physical objects appears to be natural, too, since it is the first language of man starting to master the external world. The type of experience expressed in this language precedes chronologically, psychologically and even logically other types expressed in other languages, the phenomenological one inclusive.

The fallacy of this stand is not hard to expose. The perception of physical objects by man at an early stage of his development is indeed natural and goes side by side with the mastery of the physical world. Yet this experience in the child’s development is preceded by more primitive forms of perception, such as the perceptions of colours, smells and tastes which are very different with the infant from modern physical notions. Besides, the development of man does not stop at perceptions and his growing knowledge of the external world extending to the animal kingdom, thinking and psychological processes, the sphere of social phenomena such as the relations of production, freedom, solidarity, etc. can by no means be squeezed into the physicalist paradigm.

Seeking to substantiate their doctrine, the adepts of physicalism also refer to the intersubjectivity of the language of observable physical phenomena as its characteristic feature. In their opinion, this feature accounts for the fact that it is much easier to ascertain the objectivity of one or another scientific proposition through physical reduction than through phenomenalistic analysis. Hence, they make the objectivity of knowledge contingent on the possibility of its intersubjective expression, i.e. on the community of notions and their usability with different people and different scientific quarters. In turn, intersubjectivity is made contingent on the possibility of reducing this knowledge to physical terms. Such a concept of the objectivity of knowledge is far removed from the materialistic concept identifying objectivity with independence from man and his consciousness in general, particularly if we take into account that most physical terms except those testable by direct sensory experience are considered conventional.

True, the language of physics provides a basis for intersubjective certainty in the sense that it does not deal with abstract sensory data or even perceptions, but reflects universal or general, recurrent, stable and therefore regularly observable phenomena, which is in full accord with the requirements of scientific cognition. Yet the requirements of universality and recurrence, being important as they are, do not yet ensure the objectivity of knowledge. Such physicalist views suggest the idea that intersubjectivity is characteristic not only of objects under observation, but of the observations themselves. Hence, they may be considered final in the analysis of epistemological problems. Here is, so to speak, a feedback link—from theoretical reductionism back to epistemological reductionism. One strengthens the other. Yet all observations, no matter how complete they may be and whatever their objects, remain, from the standpoint of the theory of knowledge, the perceptions of individuals.

The language of physics is incapable of providing the intersubjective basis for science in general and for scientific epistemology, in particular, if only for the fact that it constitutes a smaller part of our language and that the perceptions of physical facts are not more important— indeed, they can sometimes be even less important—than the perceptions of biological or psychological phenomena, since the perception of the physical world is inconceivable outside the human brain. Another weakness of the physicalist programme which becomes ever more obvious with the advance of science ensues from the growing differentiation of physical science itself. A question, naturally, arises: where is the limit of the reduction process? Do we have to reduce biological, psychical and social phenomena to the physics of the macroworld? Or to molecular physics-chemistry? Or to the atomic level? Suppose, we adopt the physicalist doctrine and stop at the atomic level. But what about the future? What if the world of the electron or some other elementary particle indeed opens into infinity? One can only be sorry for a philosophy which will attempt to shut the door in the face of a new generation of scientists.

Expounding some of the weaknesses of the physicalist doctrine mentioned above, many philosophers propose, in fact, to go back where positivism has started. All their ardent criticism thus turns out to be merely aimed at reinstating the phenomenologic approach (we leave aside here the numerous pluralistic versions of the combination of the empirical and the theoretical, the physical and the mental, etc.). Yet the unsuccessful attempts to reduce the mental to the physical, the biological to the chemical, the theoretical to the empirical, etc. do not mean that biology is doomed to stay forever in the cradle and content itself with exclusively empirical approach. Nor does it mean that the “irreducible residue” of biology which could not be rationalised by physics and made part of “respectable” science should always remain purely empirical.

The dialectical synthesis of the achievements of phenomenological analysis, be it in biology, psychology, social sciences or elsewhere, with the results of consistent and rational reduction is the only path to a new theory, a new theoretical fundamental discipline destined to turn biology, sociology, etc. into independent sciences which will not confine themselves, on the one hand, to the superficial description of phenomena, too specific in their external manifestation’s to be reduced to coarse physical terms, and will not dissolve, on the other hand, in physical notions degrading to a commonplace.

There has been growing evidence of late that biology, psychology, sociology and other specific sciences are beginning to turn onto this path and gain independence not as primitive phenomenological schools, but as full-fledged scientific disciplines. Darwin’s phenomenological theory synthesised with the achievements of molecular biology and genetics exemplifies a solution to the dilemma of reductionism or organicism. The same path is evidently being taken now by the modern theory of knowledge despite the predictions of epistemological reductionism. It is emerging as a product of integration of general epistemological concepts with the results of specific investigations into the nature of consciousness as such (including the social and historical factors of its development), on the one hand, and into the neurophysiological mechanisms of conscious and unconscious activity, on the other. In its advancement new scientific epistemology is casting off both the phenomenological fetters and the physicalist dogmas.