Subject Object Cognition. V A Lektorsky 1980
We have already given a critical analysis of phenomenalist epistemology which presents acquisition of knowledge as combining of subjective “sensory data.” Another, more sophisticated variety of philosophical subjectivism has much greater currency in present-day Western works on the philosophy of science. Until recently, the view prevailed amongst West European and American specialists in the logic and methodology of science that only cognition at the pre-scientific level (perception and knowledge recorded in terms of everyday language) may deal with actually existing objects. From this standpoint, scientific theoretical knowledge is different in character: it merely records in a special schematic form the regularly recurring dependences existing between the objects of pre-scientific experience. Of course, account is taken of the fact that acquisition of scientific knowledge implies employment of artificially created objects, in particular, apparatus, measurement instruments, etc.
The actual existence of the latter is by no means rejected. Moreover, it is believed that natural and artificial objects are equally objects of cognition. To be more precise, cognition is thought to be concerned with establishing definite relations between various combinations of sensuously perceived natural and artificial objects, for that is exactly what the process of measurement consists in, and scientific cognition is in this case limited to performing various measurement operations. In terms of this conception, for instance, the object studied by the microphysicist is not the processes in which electrons, positrons, and other objects inaccessible to the senses are involved but the behaviour of the corresponding devices: oscillations of their indicators, appearance of light spots on displays, etc. In other words, it is assumed that apparatus and measurement devices do not at all mediate the cognitive relation to the objects that are not given to the subject in pre-scientific experience but appear themselves as the objects of knowledge (the adherents of this view insist that naturally created things become objects of scientific cognition only in their relation to the apparatus and measurement instruments). Only that is regarded as real which can be directly observable. Everything else, including objects that are specified at the theoretical level only, are regarded as certain subjective fictions which, although playing a certain role in the cognitive process, do not by themselves have real objects as referents. As we have seen, these are the characteristic arguments of the operationalist doctrine.
This trend of thinking is based on the opposition of knowledge as a record of the directly observable to knowledge resulting from a whole ensemble of assumptions, suppositions, and arguments. Indeed, to make judgements about the behaviour of microobjects from instrument readings, one must be acquainted both with the theory of the domain of reality under study and with the theory describing the work of the device itself, enabling us to correlate the instrument readings with the corresponding characteristics of the phenomena studied. The adherents of this conception believe that the objects for which concepts are introduced in these complicated arguments and assumptions cannot be real in the same degree as the artificial and natural objects of our everyday experience — stones, trees, tables, chairs, machines, apparatus, etc. But it is easy to show a lack of logic in this argument.
In ordinary life we have to use all kinds of mediator objects all the time for the simplest observations — spectacles, the magnifying glass, or, say, simple window glass. In the same way, the surgeon uses the probe in examining a wound. In all these cases man studies those objects the relation to which is mediated by artificially constructed devices rather than the mediators themselves. To be consistent, one must also recognise that even in cases of elementary observation the subject’s relation to the object is mediated by the environment filling the space between the two. The singling out of a real object implies in all instances a reliance (usually unconscious) on a number of assumptions concerning the behaviour of the mediator object. But that is not all. As we have tried to show in the previous chapter, even those man-made objects which do not function directly as mediators in observation (labour implements, the objects of everyday life, etc.), are actually instrumental in the social mediation of perception, for it is in the objects of the “artificial environment” that the historically accumulated experiences of object-transforming and cognitive activity, are objectified, and in particular, the *standards and norms of perception are reified. The knowledge of the real object can only be singled out of the varied sensory information with the help of such norms and standards. Any perception is, as we have endeavoured to show, a complex mediating activity implying assumptions, hypotheses, schematisation, etc.
Supporters of this variety of subjectivism do not doubt the actual existence of the objects of ordinary pre-scientific experience. Moreover, in their view, those infinitesimal or extra-large objects that can only be studied with the aid of special scientific apparatus (microscopes and telescopes), also really exist. But in this case interpretation of the results of observation requires conscious use of a number of branches of theoretical physics covering, in particular, the propagation of light waves in outer space, in the Earth’s atmosphere, a system of lenses, the eye, etc. Does it not mean that knowledge acquired through of a number of assumptions, suppositions, and theoretical reasoning, can also relate to real objects? Why must we then negate the existence of actual referents, e.g., of the objects of modern microphysics? The adherents of this view reply that observable and non-observable objects must be distinguished. The knowledge of observable objects, they believe, relates to actual referents although it may imply certain assumptions, hypotheses, and arguments. As for non-observable objects, their existence is fictitious.
Indeed, not all objects, magnitudes, and parameters with which a certain scientific theory is concerned, are actually observable. Let us ask ourselves this question, however: does that mean that a certain object, now non-observable and studied at the given moment on the theoretical level only, will never become observable at all? Apparently not. For example, although the theory of molecular structure of matter was originally merely a theoretical hypothesis and there was no way of observing molecules in direct experience, the molecules of many substances can now be observed through electronic microscopes.
The justice of this is recognised by the scholars holding the view here criticised. But they point to the essential difference between molecules and such subatomic objects as the electron. The knowledge of many objects that are studied purely theoretically does not cancel the possibility of their eventual fixation in experience by some instruments of experimental inquiry. But there are theoretical objects (the electron included) which cannot in principle be observed. Only that is real which can be observed actually or potentially. Objects that are non-observable in principle do not exist as real objects — that is the conclusion drawn by the adherents of the system of views considered here.
The objects with which modern microphysics deals are indeed regarded as non-observable in principle. But what does observability or non-observability of objects and their characteristics that are studied in scientific theory mean?
Of course, only those objects can be observable which are in some way or other included in the process of acquiring sensory information. However, we have endeavoured to show in the previous chapter that already at the level of ordinary pre-scientific perception, the knowledge of the characteristics of observed phenomena is not identical to the information received through sensory channels, being determined by specific referential meanings. It is these referential meanings, object-hypotheses, the standards of perception rather than sensory information by itself, that determine what precisely is observed or perceived. In scientific theoretical thinking, theory rather than sensory information by itself determines which of the objects, magnitudes, or parameters studied in the theory can be actually or potentially observable. Theory has to take into account such circumstances, accidental relative to the objects studied, as the size of man’s body and the specific traits of his perceptual system. The fact that men as physical bodies belong to the class of macro-objects and that man as the subject of perception can therefore use only macro-objects as apparatus proves to be essential for microphysics.
These circumstances determine the possibility of including certain objects in the very process of acquiring sensory information, i..e., in the act of experiential observation. However, only within the framework of a definite scientific theory can it be established what specific objects studied by science may or may not be included in the process of observation and for what reasons, what the meaningful characteristics of objects of both kinds are, and what precisely is observed. The properties of the subject’s perceptual system are also considered in terms of the given theory. In any case, the observability or non-observability of the given objects of scientific knowledge depends in principle on definite characteristics of these objects, assumed or established in the theory, and does not directly coincide with their existence or non-existence. The objects that are not in principle observable by man can actually exist. (That means that if observations were carried out by an intelligent being strongly differing from man in its natural properties, e.g., if it were comparable in size with micro-objects, it might record in an experimental way .many of the objects that cannot in principle be observed by man. On the other hand, a radical revision of a given scientific theory and a different choice of the basic assumptions will inevitably affect the notions of the observability or non-observability as a matter of principle.)
Grover Maxwell, a modern American specialist in the philosophy of science, considers the following purely hypothetical case as an illustration of the thesis of the possibility of actual existence of objects unobservable in principle.
Suppose, he argues, that new types of micro-objects are discovered by science that are at present unknown and which interact with electrons under certain circumstances in such a way that the interaction does not disturb their eigenstate. Suppose also that a drug is discovered which alters the human perceptual apparatus — perhaps even activates latent capacities so that a new sense modality emerges. Finally, suppose that with our altered perceptual system we are able to perceive (not necessarily visually) by means of the newly discovered type of micro-objects in a manner roughly analogous to visual perception in which, as is well known, photons participate. Under certain additional conditions which we shall not characterise here, we might be able to “observe directly” the position and other characteristics of some electrons. It would follow, of course, that quantum theory would have to be altered in some respects, since the newly discovered type of microobjects does not conform to all its principles. At the same time the revision of the theory does not in this case provide any grounds for concluding that the electrons observed are not the same objects that were regarded as nonobservable in principle from the standpoint of old theoretical notions. No one will doubt the reality of the electrons observed. But if these are the same objects that were not observed earlier, it is obvious that we had no right to doubt their actual existence before that either. However improbable the hypothetical case considered here might seem, it does not involve any logical or conceptual absurdity, concludes Maxwell.
In a conversation with Werner Heisenberg Einstein said once: “From the principled positions it is absolutely incorrect to desire that a theory should be founded on observable magnitudes only. For in reality it is all precisely the other way round. Only theory decides what one can observe... Your assertion that you introduce only observable magnitudes is actually an assumption about a property of the theory on which you are working."
Thus the experimenter does not observe absolutely the same objects that are the objects of perception at the pre-scientific level. The scientist records in experience (one may even say “sees directly”) objects, processes and situations which are not ordinarily perceived at all: changes in electric voltage, a drop in strength of current in the circuit, etc. The main point here is not, of course, a change in the sensitivity of the perceptual system but the emergence of new referential meanings determined by the accepted scientific theory.
In this respect, observation aided by theory is in principle similar to ordinary perception: in both cases the referential content of what is observed is determined by a system of object-hypotheses and not by sensory information itself. It would be a mistake, however, to slur over the differences between the two processes, as Kuhn is inclined to do, for instance. The American scientist correctly stated the extremely important fact that theoretical concepts do not serve simply for interpreting the results of ordinary perception obtained regardless of their utilisation but are included in the act of scientific observation itself determining its nature and results. Yet Kuhn is hardly justified in going still further and insisting that scientific observation is of the same subjective and direct nature as ordinary perception, that in both cases there is no conscious interpretation or extended subjective reflexion. This notion of Kuhn is closely linked with the main idea developed in his book — the view that successive replacement of scientific paradigms is similar to changes in the structure of the perceptive field resulting from a “switch in visual gestalt.” But the ability to “see directly,” through the medium of apparatus readings, the objective processes indicated by the devices assumes an extensive education in which the behaviour of the devices is consciously correlated with the behaviour of the object studied. Even when this education is completed and the scientist sees directly, as it were, those objective processes which are for him meaningfully defined by a system of theoretical concepts, fixation of observed objects also assumes the functioning of ordinary pre-scientific perception: in order to observe the strength of current in a circuit from ampermeter readings, the subject must be able to perceive the ampermeter itself and the motion of its needle as objects of ordinary experience. Thus the “givenness” of the objects of scientific research in experience includes observation of two objects simultaneously: of the object of everyday experience and of that thing whose referential meaning is grasped by the subject in terms of the concepts of some theory (both of these things exist objectively and actually, although on different levels of reality, so to speak). When a person becomes a scientist, he does not cease to be the subject of ordinary pre-scientific experience and of practical activity associated with it. For this reason, the system of referential meanings which serve to maintain this activity, being included in the mechanism of ordinary perception cannot in principle be replaced by the referential meanings defined at the level of scientific cognition (though Paul Feyerabend suggests the opposite). The higher levels of cognitive activity do not cancel the functioning of the mechanisms of ordinary perception but are in a specific manner superimposed on these mechanisms incorporating them in more complex syntheses. It would therefore be wrong to insist, for instance, that the referential meanings perceived in language study are generated by language, although mastering it signifies a new stage in the interpretation of perceptions: in actual fact they are basically formed already at the pre-linguistic level of cognition, in the course of practical object-oriented activity, although language does introduce something new in them. Observation in scientific cognition does not exclude the functioning of the mechanisms of ordinary perception. The astronomer observing the Sun as a cosmic body at a certain distance from the Earth and subject in its movements to theoretically formulated laws, cannot at the same time get rid of the impression, shown to be illusory by science, that the Sun moves relative to the immobile Earth.
The development of science eliminates the illusions of pre-scientific cognition. But a scientific theoretical picture of reality does not at all imply a negation of the objective reality of those objects (as well as of their aspects and relations) with which man deals at the pre-scientific level, and neither does it negate the truth (relative truth, of course) of many assertions of the so-called common sense. This applies not only to such objects of ordinary experience as tables, trees, stones, etc., but also to properties of these objects which are commonly referred to in philosophy as secondary: colour, smell, etc. It would be inconsistent to assert that only electromagnetic waves of definite length and not colours and smells exist objectively and really, and at the same time to recognise the objective reality of the objects of ordinary pre-scientific experience, that is exactly the view held by those who divide the perceived qualities of objects into primary and secondary. Physical theories do not include the concepts of secondary qualities but, more than that, they do not include the concepts of the objects of ordinary pre-scientific experience. If we were to regard as real only those objects to which physical theories directly refer, we should conclude that in actual fact only definite combinations of atoms and molecules rather than trees, rocks, and tables exist in reality.
In actual fact, cognition at different levels deals with real objects and real characteristics of these objects. However, objective reality itself is multidimensional, it has many levels, and different objects may belong to different levels of reality. Ordinary macro-objects and the secondary qualities inherent in them exist at that level of objective reality to which ordinary pre-scientific experiences belong. Scientific cognition, physics in particular, penetrates into a deeper level of objective reality, whose existence does not cancel the reality of the objects of ordinary experience.
A system of theoretical concepts reflects the characteristics of actually existing objects, including those that are actually or essentially non-observable. The meaning of these concepts is thus not reducible to an ensemble of the laboratory operations of measurement, as operationalists believe. On the contrary, the measurement itself only becomes possible when we know what to measure, that is, when the general characteristics of the objects measured are theoretically specified. It is exactly scientific theory that makes it possible to select from the entire diversity of experience those facts and dependences between them the investigation of which will permit the scientist to single out the essential characteristics of the objects under study. Measurements that are performed outside the context of a well-developed theoretical system formulating the essential dependences between objects, including non-observable ones, turn out to be absolutely meaningless, as a rule. And it is not just the fact that measurement results are subsequently theoretically interpreted that is important here. Well-developed theoretical conceptions are a necessary premise of meaningful measurements themselves, for only the former indicate the object and the mode of measurement itself. The measurements performed outside of a correlation with the essential dependences of a definite type of objects do not express, strictly speaking, an act of cognition, just as acquisition of information from the environment uncorrelated with objects is not yet cognition.
“We often hear,” writes Kuhn, “that they [the laws expressing quantitative dependences] are found by examining measurements undertaken for their own sake and without theoretical commitment. But history offers no support for so excessively Baconian a method. Boyle’s experiments were not conceivable (and if conceived would have received another interpretation or none at all) until air was recognized as an elastic fluid to which all the elaborate concepts of hydrostatics could be applied. Coulomb’s success depended upon his constructing special apparatus to measure the force between point charges. (Those who had previously measured electrical forces using ordinary pan balances, etc., had found no consistent or simple regularity at all.) But that design, in turn, depended upon the previous recognition that every particle of electric fluid acts upon every other at a distance. It was for the force between such particles — the only force which might safely be assumed a simple function of distance — that Coulomb was looking. Joule’s experiments could also be used to illustrate how quantitative laws emerge through paradigm articulation. In fact, so general and close is the relation between qualitative paradigm and quantitative law that, since Galileo, such laws have often been correctly guessed with the aid of a paradigm years before apparatus could be designed for their experimental determination."
Using as an example the revolution in chemistry carried out by Dalton, Kuhn shows that one and the same operation applied to nature through different paradigms may indicate quite different aspects of the patterns of nature. Moreover, an old measurement operation in a new role may produce other experimental results. 
Einstein’s analysis of the procedures for measuring time (we may recall here that it was this analysis that was the starting point of Bridgman’s formulation of the doctrine of operationalism) is far from being a mere description of a “directly given” operation, implying in actual fact a number of theoretical premises. Simultaneity can only be defined if we postulate that the velocity of light in vacuum is the same in all directions and invariant relative to the motions of source and receiver. This postulate is logically prior in the special theory of relativity to any experimental measurement of the velocity of light, because it is used in the very definition of the time scale at distant points. 
Even the simplest prescriptions for measurement operations used in science usually follow from theoretical considerations. True, instructions for laboratory operations may be formulated in such a way that their theoretical foundations will be camouflaged, but that does not mean at all that these foundations do not actually exist.
Thus scientific theories determining the meaning and character of experimental procedures contain as often as not knowledge of such objects and parameters which are not observed and are not measured directly. Let us now note that there are also scientific theories, the most fundamental ones, actually, (usually referred to as substantive in the literature on the methodology of science) which are not applied directly to interpretation of observation data at all but are only correlated with the empirical world in combination with other theories (the latter are commonly referred to as “observational” or “interpretative”) and on condition that a number of additional assumptions are made. Generally speaking, the question of experimental application of a fundamental scientific theory (and, in this connection, of its experimental verification) proves to be far from simple, and usually the search for methods of experimental application of such a theory requires considerable efforts for further elaboration of the theory itself and the construction of a number of additional theories, hypotheses, etc..
An isolated theory is never directly linked up with an experiment: an act of such association implies the use of a whole hierarchy of theories and hypotheses including those from other domains of knowledge, the theory of experimental devices, a number of hypotheses linking up the non-observable with the observable, certain idealisation assumptions, etc. The experimental data themselves are formulated in terms of a definite (“interpretative,” or “observational”) theory.
We shall not consider in detail the important problem of the interrelation of the empirical and theoretical components in scientific knowledge. In the context of the problems of immediate interest to us, it is important to stress the relative independence of knowledge recorded in theory from various (potentially infinite) ways of empirical or experimental application of that knowledge. Of course, theory must be experimentally tested, that is to say, it must be linked up through a whole chain of mediations with experimental results. The question as to how this verification is carried out is fairly complicated and is now intensively studied in the literature on the methodology of science. At the same time the meaning, the content of theoretical knowledge, is not directly determined by the modes of its association with experimental data.
In the Western philosophy of science, the conception of logical positivism has until recently prevailed; it regarded a scientific theory as an uninterpreted formal calculus given meaningful, empirical interpretation in terms of the so-called correspondence rules connecting the terms of the theoretical language with those used in the sentences of observation allegedly recording only direct sensory data. The rules of correspondence must, from this standpoint, be necessarily included in the structure of the scientific theory itself, for only these rules transform an uninterpreted formal calculus, which refers to nothing, into a theory, that is, knowledge about a definite class of objects.  In reality, however, the meaning or content of a theory is not determined directly by its empirical application’s, for meaning is specified “from above” rather than “from below,” through a model interpretation of theoretical assertions. The number of potential modes of empirical application of the given theory is in actual fact infinite (and all possible applications cannot be foreseen in advance), whereas the number of “correspondence rules” used in the given theory is strictly limited, according to logical positivism. And finally, the most important point is this. Assertions linking the given theory with experimental results do not simply correlate theoretical and non-theoretical, “purely observational” terms but themselves belong to an auxiliary theory (auxiliary relative to the given one). Thus these statements (it would be imprecise to call them “correspondence rules,” in any positivist sense) are not included in the structure of the given theory itself, which is relatively independent from various possible modes of its empirical application. Knowledge recorded in a theory reflects the essential dependences between real objects, far from being a set of prescriptions for carrying out laboratory operations; neither is it restricted to listing the ways of direct practical transformation of objects.
Here we would like to draw a far-reaching analogy between theoretical knowledge and knowledge recorded in ordinary perception. One may recall that the referential meaning of the perceptual image is amodal, that is, relatively independent from the type of modality (visual, auditory, tactile, etc.) in which perception is implemented. This is apparently a general property of the cognitive relation — relative independence of knowledge from the modes of its correlation with actual sensory information (the independence is indeed relative, for knowledge is impossible in the absence of any mode of such correlation).
Thus cognition may be a reflection of real objects both in ordinary perception and in scientific thinking — at both the empirical and theoretical levels of the latter.
The interrelation of theory and its objects poses yet another problem, one that we have not touched on so far. Implementation of theoretical cognition involves the adoption of a whole series of idealisations, i.e., of assumptions or suppositions which essentially do not correspond and even sometimes contradict what can be directly observed.
For instance, the abstraction of actual infinity that was widely used in classical mathematics is based on the assumption that we can count the entire natural number series, although that is clearly impossible in experience. In constructing his geometry, Euclid assumed that any section of a straight line, however short or long it might be, may be divided into two with the aid of ruler and dividers. In classical physics, it is assumed that we can measure velocity at any given point of the path, that is, that we can measure instantaneous velocity.
The laws formulated in scientific theory also refer to certain ideal cases. Therefore their employment for the description of actual experience and for predicting future empirical facts is only possible if a whole series of additional factors are taken into account, those which are ignored by theory revealing the law “in pure form.” Inasmuch as it is impossible to consider all these factors theoretically, there will always be a kind of gap between the flow of empirical events predicted by the given theory and that which we directly observe in experience, although this gap becomes smaller and smaller as science develops. Lenin pointed out the role of idealising assumptions in Marx’s development of the scientific theory of political economy: “'Concretely impossible’ is not only realisation as put forward by Marx, but also land rent as put forward by him, and average profit, and the equality between wages and the value of labour-power, and much more besides. But the impossibility of something being realised in a pure form is not a refutation.” 
Idealisation means not only adoption of some assumptions in formulating theoretical laws but also in constructing idealised objects. The “material point,” a concept widely used in classical mechanics, is an example of such an idealised object. It is assumed that such an object, which exists in time and space, has mass (as all real bodies) and at the same time it has no extension, that is, coincides in fact with the mathematical point in this respect. Another example of an idealised object is “incompressible liquid” studied in hydrodynamics. Clearly, idealised objects have no real referents; they are constructions of theoretical thinking (sometimes called “intratheoretical,” distinct from “extratheoretical” objects, that is, those which exist independently of theory). The question naturally arises, what is the reason for such fictitious objects?
Constructing idealised objects is a way of formulating idealised assumptions and a method for establishing, “in a pure form,” certain dependences expressed in theoretical laws. For example, if a real body moves under the action of a force applied to its centre of gravity, the motion of that centre does not depend on either the geometrical form of the body or the distribution of mass in it but only on the overall quantity of mass. The centre of gravity moves as if the entire mass were concentrated in it, i.e., like the idealised object known as “material point.” Establishing with the aid of the idealised object the dependences obtaining in the motion of bodies under the impact of a force applied to the centre of gravity, we get a key to the whole of the complex system of dependences existing in the diverse cases of real mechanical motions.
What is the nature of the dependences formulated in a theory on the basis of a number of idealising assumptions? Should they be regarded as mere subjective “simplifications” or “schematisations” of actual empirical situations (this interpretation of the idealisation procedure is not at all rare)?
It appears that idealisation cannot be reduced to “simplification” of that which is given in experience. In idealisation one not only ignores certain factors given in experience but also formulates in some cases assumptions which cannot be realised in experience. Idealisation can therefore serve to establish essential, objective and real dependences, for revealing various connections “in pure form” is exactly the discovery of actual substantive relations which do not directly coincide with dependences characterising the phenomenon and registered in experience. However, one may accept that a theory formulating definite dependences in a system of scientific laws reflects objective, real substantive relations, while believing at the same time that all theoretical objects constructed with the aid of theory have no real referents, that is, are idealised, fictitious objects playing a purely auxiliary role in formulating definite dependences. It will have to be recognised in this case that only those objects are real that are fixed at the pre-scientific level, that is, through ordinary perception and in terms of everyday language. Those who hold this view argue that knowledge of any theoretical object is always introduced through a number of idealisations. That means that the object itself is always an idealisation, that is to say, it has no real referent leading “intratheoretical” existence, so to speak. 
Let us note, however, that the knowledge, recorded in ordinary perception, about objects the reality of which does not occasion any doubts, also implies a whole series of assumptions and hypotheses; we considered this point in the previous section. True, the assumptions on which perception is founded, as distinct from the idealisations used in science, are implemented in the sense experience itself and are therefore not even consciously realised, as a rule. It is important in any case that, far from excluding the possibility of correlating knowledge and real objects, adopting a number of assumptions and suppositions is a necessary condition of such correlation. Where there are no definite assumptions, it is impossible to separate a real object from a subjective illusion. Let us note further that dependences formulated by science “in pure form” (their establishment naturally assumes the adoption of a number of idealisations) need not necessarily have only “theoretical objects” as referents, that is, objects the knowledge of which is only possible at the theoretical level. They may also be objects fixed in ordinary experience, the reality of which causes no doubts. For instance, Marx’s Capital establishes the laws of the capitalist mode of production “in pure form” treating exclusively of real objects — commodities, men, their activity, machines, etc. Of course, the objects themselves are considered from a definite standpoint carefully formulated in theoretical assumptions, the elaboration of the theoretical system involving consistent analysis of those factors that had to be ignored at the initial stage (the famous method of ascending from the abstract to the concrete). Let us note, finally, that science does not at all identify theoretical objects with idealised ones. That means that at least some of the objects the knowledge of which is introduced at the theoretical level are accepted as existing objectively and really: molecules, atoms, electrons, positrons, virtual particles, events in the four-dimensional spatio-temporal continuum, the field, quarks, etc. This point is extremely important, for the very distinction between idealised and non-idealised objects, that is, real ones, is only possible and meaningful if we know which objects are real and what their characteristics are.
This knowledge is specified not only extra-theoretically (e.g., with the aid of ordinary perception). The scientific theory itself introduces notions of such actually existing objects which may not coincide with the objects fixed in ordinary, pre-scientific experience or may even be non-observable (actually or in principle). Importantly, the assumption concerning the existence of a number of real objects the knowledge of which is specified only at the theoretical level is usually connected with formulating the so-called nucleus of a research programme which serves as a foundation for subsequent development of a series of scientific theories; it determines to a considerable degree the heuristic possibilities of the given programme. Idealised theoretical objects are constructed only relative to real ones; they thus lack certain characteristics of real objects or, on the contrary, possess properties impossible in real objects. It follows from this, among other things, that idealised objects may be idealisations not only of the real objects which are given at the extra-theoretical or even extra-scientific level (as a rule, the actual prototypes of idealised objects are interpreted in exactly this way), but also of the real objects knowledge of which can only be acquired theoretically. It is essential at the same time that the objects which are assumed at the given stage of the development of science to be actually existing, may be either rejected as completely fictitious in the course of changes in scientific conceptions (that was the destiny, e.g., of such a theoretical object of classical physics as ether) or relegated to the status of idealised objects (the atoms of classical physics as compared to the actual atoms with which modern physics deals).
If the structure of theory should be considered purely formally, without regard for its various meaningful layers, and if the meaning of the theoretical system should be reduced to a set of prescriptions for measurement operations, the difference disappears, of course, between idealised and real theoretical objects: all objects specified at the theoretical level will seem mere auxiliary constructs.
However, we shall try to demonstrate that the content aspect, the referential meaning of theoretical constructions cannot be ignored.
The procedure usually referred to in logic and the methodology of science as idealisation includes in actual fact a number of different procedures. Along with idealisation proper, aimed at establishing the substantive dependences of the processes under study, and thus permitting to study a definite system of connections “in pure form,” procedures are usually included here which are not in actual fact idealisations but might more precisely be referred to as “simplifications.” The latter are widely used for convenience of calculations (e.g., representing the electron orbit as circular, application of geometrical optics as a convenient simplification for purely practical purposes, etc.). It appears that the reduction of the entire range of devices used in constructing knowledge about theoretical objects to idealisation only greatly impedes the analysis of the nature and structure of scientific theory.
Thus the application of the idealisation procedure as a necessary element of constructing a scientific theory does not eliminate the possibility of studying such real objects the knowledge of which is obtained only at the theoretical level.
Finally, let us consider yet another argument used in contemporary Western literature on “the philosophy of science”: the assertion of the impossibility of obtaining adequate knowledge about real objects studied at the theoretical level.
We are dealing here with representing theoretical statements as an ensemble of the so-called Ramsay propositions. For this, the given theory must first be axiomatised, and then a conjunction formed of all the axioms of the given theory and of the “correspondence rules” linking theoretical terms with those of observation. This conjunction may tentatively be represented as – – p – – – q – – – ..., where p and q are theoretical terms and dashes signify those propositions of the given conjunction of which p and q are terms. Then p and q are replaced in this conjunction by the variables connected with the existential quantifier. As a result, the so-called Ramsay propositions are obtained: (∃ f) (∃ g)... (– – – f – – – g – – ...). On the content plane, the Ramsay method of eliminating terms pertaining to theoretical objects may be illustrated as follows. If, for instance, the theory originally contained the assertion that there exist atoms with such and such characteristics, and that the processes in which they participate are associated in such and such a manner with what is observed in experience, after eliminating the terms pertaining to the theoretical objects by means of the Ramsay propositions, we shall obtain the proposition that, if there exist certain non-observable objects (of indefinite nature) connected in a definite manner with what is observed in experience, we shall empirically state such and such facts. It is easy to show that after the terms pertaining to theoretical objects are eliminated by the Ramsay propositions, the theory will yield the same observation propositions as were yielded by the original axiomatised theory. This is taken as proof that a theory rewritten in Ramsay propositions has the same content as the original version of the theory. But the new variant of the theory does not contain direct knowledge of the theoretical objects. They appear as something unknown, as an x which, though recognised as existing, is not an immediate object of knowledge. Grover Maxwell, mentioned above, infers from this that theoretically fixed real objects, as distinct from empirical ones, may only be cognized in an oblique, symbolic way, that is, knowledge of these objects cannot be regarded as adequate. 
It is easy to show, though, that this conclusion is untenable. Let us point out, first of all, the inadequacy of presenting the very structure of the theory in this case. We have already commented on the unjustifiability of presenting a theory in terms of an axiomatised calculus which is given a meaningful interpretation exclusively in terms of “correspondence rules” linking theoretical terms with those of observation. In actual fact, science describes experimental data in theoretical terms, and “purely” observational non-theoretical terms are not employed in the production of scientific knowledge. For this reason “correspondence rules” in their positivist interpretation are non-existent, strictly speaking. It is therefore impossible to outline the potential empirical applications of this theory (through the mediation of other, “auxiliary” theories, as a rule) beforehand: they are not fixed, and are discovered gradually, along with the elaboration of the given and other theories. It is therefore difficult to compare two theories (or two versions of a given theory) in terms of the possibilities of their application in experience. Yet even if we accept that the presentation of the structure of a theory used in the above argument about the elimination of theoretical terms is justifiable, the very possibility of rewriting the theory in terms of the Ramsay propositions arises only when this theory has already been formulated. It is easy to see that if the task was, from the outset, to construct a theory in which the terms pertaining to theoretical objects were eliminated according to Ramsay’s rules, we could hardly have a single theoretical system. The assertions regarding the connections in which theoretical objects are included are determined by the meaning, the content ascribed to these objects. If the nature of the theoretical objects is unknown to us (and rewriting a theory in terms of the Ramsay propositions compels us to recognise precisely that), it is not clear why these x’s, the existence of which we postulate according to the Ramsay rules, must be connected by such and such relations. Rewriting a theory in terms of the Ramsay propositions looks like a clever trick which does not express real connections between theoretical assertions and which itself only becomes possible on the basis of the unfolding of the content of the theory, assuming as it does a knowledge of the meaningful dependences between theoretical objects. The possibility of obtaining knowledge about certain real objects only on the theoretical level does not at all make this knowledge inadequate or defective. It may be assumed that the experimental observability of the object facilitates acquisition of knowledge about it, but this fact has no direct relevance to the substantive meaningful characteristic of this knowledge. The fact that a non-observable object becomes observable (which sometimes happens, as we pointed out above) does not prove that our previous knowledge of this object was “symbolic” and that only now does it become genuine. On the contrary, the justifiability and adequacy of knowledge obtained at the theoretical level is here confirmed.
Of course, many essentially non-observable objects with which theory is concerned radically differ in their characteristics from ordinary observed bodies. (For instance, the particles differing in their position in space but identical in the rest of their properties, are regarded as identical in quantum mechanics.) However, the fundamental difference between objects of different types does not follow from their observability or non-observability but from their different real nature, for it is the latter that determines the possibility or impossibility of their observation.
In conclusion, let us touch on some general points.
In pre-Marxian philosophy, it was usual to interpret knowledge of real objects (strictly speaking, knowledge can only relate to real objects, for otherwise it is not knowledge but something else) as something more or less immediately given. Our analysis of some methodological problems involved in the study of the structure and content of scientific knowledge proceeded from the fundamental propositions of Marxist philosophy about the dialectically mediated nature of any knowledge. We have endeavoured to show that the existence of definite assumptions does not at all exclude the possibility of relating knowledge to an object existing in reality, independently of an act of cognition; on the contrary, the characteristics of real objects can only be established on the basis of a number of premises, assumptions, hypotheses, etc. (of course, on condition that these assumptions and hypotheses are in one way or another justified in practice, however complicated the justification might be).
Marxist-Leninist philosophy emphasises the genetic and functional dependence of cognition on practical activity with objects directed at transformation of natural and social reality. It is also pointed out that cognition differs essentially from practical activity on a number of vital points. Cognition is also a definite form of the subject’s activity, but this activity is aimed, at any level and in any form, at revealing the substantive content of a system of real objects. The subject’s activity is only possible in the framework of definite assumptions about the content of these objects and cannot therefore be viewed as simple constructing or creation of a certain ensemble of artificial structures without real referents. In this case, cognition can deal with real objects even if they are not in principle given in experience. Cognition is an activity of a special kind which assumes the use of definite referential meanings, object-hypotheses, norms, etc., and aims at reconstructing a system of substantive relations between real objects. The operations included in cognitive activity, both experimental ones and the operations of measurement, have meaning only in the context of definite assumptions about the real nature of the objects studied.