The “Object Theoretic Operational” View of Natural Science
Arkadiy Lipkin
Abstract
In this paper, I argue that the conceptual changes that occurred in the structure of physical knowledge during the second half of the 19th century, are reflected by the concept of the “primary ideal object” (PIO) and its implicit definition within appropriate systems of statements, called a “nucleus of a branch of physics” (NBP). Within an NBP focus shifts away from discovering “laws of nature” to observations of a physical object (system) and its states, while the distinct notion of “measurable” replaces the vague notion “observable”. On the basis of this notion, the roles   of physical models and measurements within physics, different kinds of work, experiments, and laws are discussed. Next follows a discussion of different levels of change in science, after which this distinction is compared to Kuhn’s model. Finally, I present a new combination of “realism” and “constructivism”, which differs from both the “constructive empiricism” of van Fraassen and from different “empirical realisms”.
1. Introduction
Most philosophy of science takes as its starting point the revolution in physics that occurred in the beginning of the 20th century. By beginning here, however, one may fail to reflect the deeper changes in the structure of physical knowledge that had occurred about half a century earlier. This structure can be found in modern courses of theoretical physics like, for instance, that of Landau and Lifshitz (1977). The earlier and often underestimated transformation was characterized by the appearance of the first theoretical physics departments at Universities by the end of 19th century. Scientists such as Galileo, Newton, and Euler were searching for the laws of motion, since, to them, what should count as objects of motion seemed obvious. But this situation changed in the middle of 19th century. Within the field(s) of electrodynamics (and thermodynamics), there now arose problems with the object of motion as well. As a result, the representation of a dynamical phenomenon as the transition of a physical system (object) A from state (SA (1)) to state (SA (2)) was established in theoretical physics. That is, the physical system (the object) and its states has since then been seen as central, whereas the “law of motion” (a law of Nature) became a feature of the physical system. Such descriptions in theoretical physics became an adequate way of creating new physical essences in the 20th century. This kind of representation, with its new structure of physical knowledge and with its specific combination of constructivism and realism, of rationalism and empiricism, is essential to the new theoretical physics. This change in representation, however, was not reflected in the philosophy and methodology of science. My “theoretical physics primary ideal object” view is an attempt to describe and properly acknowledge this structure. 
The basic statements of my view are presented in Section 2. On the basis of these, I discuss the role in physics of physical models and mathematics (Section 3); different kinds of work, experiment and laws (Section 4); and the very important question about the role of measurement (Section 5). My view suggests 4 levels of Conceptual Changes in Natural Sciences, two of which are compared to two levels of Kuhn’s model (Section 6). Finally, the last Section is devoted to an analysis of the combination of constructivism and realism which is fundamental to this view (Section 7).
2. The Basic Statements of the “Theoretical Physics Primary Ideal Object (PIO)” View
It is an important feature of the “The Theoretical Physics Primary ideal Object View” that it includes a two level hierarchy consisting of physical objects, which can be seen in analogy to the hierarchy that exists between geometrical objects. In geometry (as well as in this view), there exist primary and secondary ideal objects. The secondary ideal objects – SIOs (such as a figure in geometry or an electrical discharge in electrodynamics) – are constructed (or defined) using primary ideal objects – PIOs (such as a point, a straight line, and other primitive geometrical concepts; and such as a charged particle and an electromagnetic field in electrodynamics). This is the essence (and definition) of an SIO: An SIO is defined explicitly through PIOs. PIOs are thus to be defined in a different manner. Until the middle of the 19th century, PIOs were assumed to be indeterminable but uncontroversial concepts in both geometry and physics. This situation, however, changed with the appearance of non-Euclidean geometry and Maxwell’s electrodynamics (the concept of an electromagnetic field was hard to comprehend by means of  simple abstraction, the way “material point” is perceived in mechanics). In geometry, D. Hilbert suggested the solution to this problem through an implicit definition of PIOs by using a geometrical axiomatic system. This implicit definition consists of a fixed number of statements with every statement containing more than one defined concept (e.g. “through any two points; only one straight line can be drawn”). If there is a sufficient number of such statements, then all the concepts can be defined unambiguously. (This implicit kind of definition has some resemblance with a system of equations {fk (x1, … , xk) = 0}, where x1, …, xk resemble defined concepts, including PIOs.)
The same procedure, although initially without sufficient reflection, was applied in physics, which aimed at a level of strictness equal to the one in mathematics. Consequently, significant changes occurred in the way the structure of the basis of physics was construed. In the frame of contemporary theoretical physics, this structure has received a much clearer representation. As a result, theoretical physics today consists of separate branches (such as classical and quantum mechanics, electrodynamics, etc., which can be found in theoretical physics courses like (Landau and Lifshitz 1977)), each with their own foundation. These foundations each consist of an appropriate system of statements, which define the basic concepts, including PIOs and procedures for building SIOs using PIOs. We will name each such appropriate system of statements a “nucleus of a branch of physics” (NBP). The NBP implements the unambiguous definitions of the PIOs in the branch.
The common structure of the NBP for all branches of physics is represented in Fig. 1. Here, SA is a state of a physical system A, {SA}M  is its mathematical image, EM is the equation of motion which describes the connection between states, <P| and |M> are operations of preparing the system and its initial state, and operations of measuring (its essence is comparison with standards) for measurable quantities (measurables). (It should be noted that there is a difference between ideal and real operations (ideal and real smooth ramps, solid meter, etc.), which is not shown in Fig. 1.) 
The procedures used in building SIOs out of PIOs enter into the NBP too (building a many-particle system in classical mechanics using Newton’s 3rd law is the simplest example, while another example could be how this production is used for “one-particle” SIOs like an electron, proton, neutron, or different liquids which are building by assigning a specific set of measurables to the corresponding PIO).
There may exist a concept of external action F, like force in classical mechanics (and interaction in the case of  a many-particle system), too, which need to be represented in the model  and whose mathematical images enter into the equation of motion (for the sake of simplicity this isn’t represented in Fig. 1).

THEORETICAL PART (T)

EM
Mathem: {SA(1)}M                                SA(2)}M

Model:      SA(1)                                    SA(2)

(simplest A= Primary Ideal Object (PIO))

    <P|                                                                 |M>

Fig. 1: A Nucleus of a Branch of Physics (NBP)

Any branch of physics consists of an NBP, its PIOs, SIOs, and its consequent theories. The SIO is an ideal ontological object model from which, since the theoretical description of PIOs is known, theory ensue. That’s why – on the one hand –  Fig. 1 describes an NBP and defines the PIO if A is the PIO (i.e. the simplest system of the branch), and why – on the other hand – the central part of the scheme describes the theory of behavior of an SIO, i.e. a phenomenon, if A is an SIO. Furthermore, one should bear in mind that an SIO can be built using PIOs from different branches of physics (the motion of a charged body in liquid can, for instance, be described using  PIOs from  mechanics, hydrodynamics, and electrodynamics). Different branches of physics differ from each other in that their system A and its states differ in kind. Consensus on this issue was reached in physics in the second half of the 19th century, but since then it has become easy to extend this view onto previous physics, because Euclid’s geometry functions both as a paradigm for the theoretical description for the physics of Galileo and Newton, and for this new kind of theoretical physics. 
The concept of state is the most difficult concept there. This is a concept which describes the motion (process) of a system and gives us opportunity to answer every question concerning the system’s behavior that is possible within this branch of physics. This definition partly coincides with van Fraassen’s: “if we knew the state, then we would know all there is to know about how the system will develop if left alone and how it will react if acted upon” (van Fraassen 1980, p. 275). The main difference between the two definitions is the exclusion from my view of measurement as the variable of such ‘action-upon’. In dynamics, a state is connected to a moment of time (this is the reason why ‘time’ plays a special role in dynamics in comparison to other measurable quantities), but this isn’t necessarily so. There may be other parameters, which order states. Stationary states are, for example, ordered by energy levels and other integrals of motion, and in thermodynamics  temperature or other parameters play this role (Lipkin 2001a). One can speak evenly about only the initial and final states which exist  in any physical process.
Now, let’s look at main features and consequences of this view.
3. The  Role of Physical Models and Mathematics in Physics
According to my "theoretical physics PIO-view", mathematics can be considered an element of the NBP-structure. It is included as mathematical representations, and the central role played in physics by mathematics is ascribed to physical models. The latter, however, fall outside of the positivistic views of physics which has been (and often still is) the starting point for both physicists and philosophers in the 20th century. Actually, there exists only two levels in such positivistic views: the mathematical (consisting of equations) and the empirical (consisting of measurements or observations). 
In his lectures on quantum mechanics, the famous Soviet theoretical physicist L.I. Mandlstam spoke of the structure of any physical theory.  “A bit schematically,” he said,
one can say that any physical theory consists of two  complementary parts [which corresponds very precisely to the  Math-level  and the level of measurement in our NBP]. I begin with the second part. These are theoretical equations  – Maxwell’s equations, Newton’s equations, Schrödinger’s equation, and so on. Equations simply form a mathematical apparatus (device). Some symbols enter into these equations: x, y, z, and t, vectors E and H, and so on. The first part of the physical theory is that which forms the connection between these symbols (values) and the physical objects, to which they are connected via the representation. This connection is realized by concrete cookies (concrete things such as standards and concrete measurement processes – the finding of coordinates, time and so on by using  of rules, clocks, and so on). I.e., at first we have transition from objects to figures (numbers) by cookies and then goes mathematics and thereafter inverse transition to express the achieved result as physical” [Mandlstam 1972, pp. 326-327].
Thus, in Mandlstam’s scheme, there exist only two levels: a mathematical one, which is represented by equations of motion, and the one consisting of measurements, which are procedures of comparison with standards.
The covering up of the model level is a result of the popular opinion that the distinctive features of modern physics lies in experimentation (which is often identified with measurement), and in mathematics. A view of this kind resembles very closely the instrumentalist view, which was formed in connection to the positivistic philosophy of E. Mach, A. Poincare, and others. In the pathos of the struggle with the mechanicists, Mach and his sympathizers – including many of the originators of the new physics – began to deny that models played any role in physics. In this context, the huge success of Einstein’s Special Theory of Relativity, which consisted of only two important levels – one of equations, and one of measurements, was seen as a token of the victory of the instrumentalists. The instrumentalist view was therefore inherited by the major part of the following generation of theoreticians within the physical sciences. 
The same situation has occurred, although at a later point in time, in philosophy of science. Thus, according to the “Received View” (RV), which “occupies a central place in logical positivism” we have statements such as this:
A scientific theory is to be axiomatized in mathematical logic (first order predicate calculus with equality). The terms of the logical axiomatizatioon are to be divided into three sorts: (1) logical and mathematical terms; (2) theoretical terms; and (3) observational terms which are given a phenomenal or observational interpretation. The axioms of the theory are formulations of scientific laws, and specify relationships holding between the theoretical terms. Theoretical terms are merely abbreviations for phenomenal descriptions. (Suppe 1974, p. 12; italics added).
(We see the same two levels of description in a later, more structuralistic view, where P. Suppes in his paper ‘What is a Scientific Theory’ describes what he calls ‘the standard sketch of scientific theories’ as follows: “A scientific theory consists of two parts. One part is an abstract logical calculus. In addition to the vocabulary of logic, this calculus includes the primitive symbols of the theory, … The second part of the theory is a set of rules that assign an empirical content to the logical calculus” (Suppes 1969, p.56).) And “it is little exaggeration,” wrote F. Suppe, “to say that virtually every significant result obtained in philosophy of science between the 1920s and 1950 either employed or tacitly assumed the Received View” (Suppe 1974, pp. 3-4). 
The model level in Fig. 1 is the central part of the scheme. The modeling, i.e. the making of models on the basis of phenomena, is the primary kind of work in physics. The claim that theoretical physics can (and should) be identified with mathematical physics, is the result of a positivistic aberration. Of course the mathematical kind of work is widespread in theoretical physics, and of course it is very important, but without a model of phenomena we do not achieve a sufficient level of understanding, although we can describe the results.
The central role played by physical models in physics is manifested by asking: “What is the concept of “understanding” in Physics?” In his paper, ‘What is the concept of “understanding” in Physics?’ (Heisenberg 1969), Heisenberg discussed what the word “understanding” could mean in theoretical physics. There isn’t just one simple answer to this question. But we can find many examples. In all cases, “understanding” in physics is constrained by the construction of an ontological model. I am here thinking of examples such as planetary motion, turbulent motion of fluids, and superconductivity. What these examples testify is that the feeling of having arrived at some form of “understanding” of a phenomenon, appears only after the construction of an ontological model of the physical phenomenon. We can see the same ideas present in statements such as this: “We have understood a group of phenomena when we have found the right concepts for describing these phenomena” Or this: “By constructing simplified models and by demonstrating that these models do show the characteristic features of the phenomena, we convince ourselves that the concepts are correct (e.g., in the theory of superconductivity), that we have “understood” the phenomena”.
The level at which models exist is manifested in classical and quantum mechanics by using different “mathematical representations” for the same physical problem such as Newtons’s, Lagrange’s, and Hamiltons’s in classical mechanics; and Schroedinger’s and Heisenberg’s schemes in quantum mechanics.
4. Different Kinds of Work, Experiment, and Laws in Physics
The next point concerns the presence of two types of objects: PIOs and SIOs. The discerning of these two types of ideal objects – ‘primary’ and ‘secondary’ – is one of the theoretical cornerstones of the PIO-view of science. This leads to the existence of two kinds of scientific work: the PIO-kind of work, which creates new PIOs, and the SIO-kind of work, which makes use of the existing PIOs for explaining and predicting the occurrence of phenomena by means of modeling. These two kinds of work resemble closely, on the one hand, T. Kuhn’s concepts of “scientific revolution” and “normal science” and, on the other, Einstein’s “principal” and “constructive” theories.
Which one of the two approaches one chooses is the existential choice of any scientist. To illustrate this point, we can make use of a very interesting case from the history of electrodynamics. The case I have in mind is the one where Faraday and Maxwell, in order to fulfill their intentions of ordering the known set of empirical laws, had to create a new PIO such as the electromagnetic field by doing the PIO-type of work. Meanwhile, their German colleagues tried to get along relying only on the SIO-type of work. The latter kind of work was successful until the end of the 19th century, when electromagnetic waves were discovered. 
These two kinds of work correspond to two kinds of experiment. There is, on the one hand, the PIO-experiment associated with the PIO-kind of work, and there is, on the other, the SIO-experiment associated with the SIO-kind of work. To be able to differentiate these two types of work, I will make use of E. Hutten’s distinction between two types of models: “models OF” (something existing) and “models FOR” (something not yet existing). In a PIO-experiment, the PIO, which is created de novo, is approached through the empirical object. The PIO functions as a model FOR the empirical object, which consequently in this sense hasn’t existed before the creation of its corresponding ideal object. In an SIO-experiment, the SIO functions as a model OF an already existing empirical object. In this case it is the approach of the empirical object that is primary.
An SIO-experiment can exist both in a natural (material) and in a mental form, i.e. in thought. A thought experiment is possible due to the fact that SIOs are built using PIOs, whose behaviour is known via a theoretical description. This is the reason why thought experiments are widely used by theorists. (In case the equation of motion becomes too complex, it can be solved by computer for many different values of different quantities. This is the essence of the “computer experiment” or “mathematical modeling simulation”).
The essence of a PIO-experiment is the realization of the PIO, whose design is up to this point only theoretical. Actually producing a PIO-experiment is more complicated than the mere idealization of some experiment. One of the main concepts of my PIO-view is the concept of the PIO-experiment, which becomes connected to PIO-kind of work as new PIOs are created. At exactly this point, then, one sees a complex interweaving of theoretical and operational elements, which makes the common positivist dichotomy “empirical – theoretical” or “observable – non-observable” inadequate. 
The theory of falling bodies in Galileo’s Discourses can act as a standard example of the PIO-kind of work, where new PIO are created, i.e. vacuum in this case. If we look at Galileo’s original texts, we discover that his arguments were not in general based on empirical observation (as F. Bacon thought), but rather on the theoretical belief that “Nature tries to use the simplest and the easiest means in all of its devices... Therefore, when I note that a stone set in motion and falling from a considerable altitude acquires more and more velocity, should not I assume,” he says, “that this increment takes place in the simplest form? If we examine the phenomenon more closely, we will find that there is no simpler incrementation than one which occurs uniformly” (Galilei 1900). Galileo’s ability to reasoning physically is well demonstrated in a long digression on the problem of a thrown body, which takes place on the “fourth” day of Discourses. First of all, the law of motion is presented, namely that bodies fall at a constant acceleration (on the “third” and “fourth” days), and as a result of mental experiments, the three aspects of the process are separated, viz., body, vacuum, and medium. The concept of a body remains invariable (evidently because the moving stars of the sky, the movement of which have been discussed by astronomers ever since ancient times, have clearly defined images), and because the elements of the physical model to be created are ‘vacuum’ and ‘medium’. Galileo introduced the vacuum as the ideal medium, in which the ideal (the imagined) and the real (the actual) fall of a body will be identical. The medium thus becomes the cause of any deviation of real from ideal motion (this should be seen in contrast to the view held by Aristotle, who saw the medium as the source of the motion ). The conscious nature of Galileo’s rationalistic approach is confirmed by one of his letters to Baliani (from the 7th of January 1639), where he claims that it doesn’t matter to him if some features of his picture of movement of falling bodies do not correspond to real bodies falling, since nobody reproaches Archimedes for the absence in Nature of bodies that move in accordance with Archimedes’ spiral (Galilei 1906, t. XVIII, p. 11-12).
Allow me to briefly note that the pair “vacuum – medium” can never been falsified (in the Popperian sense). However Galileo looked at his model like an engineer would look at a project, and he linked his notion of vacuum to real material by introducing into his theory such ‘structural elements’ as smooth ramps and other structural components (which later became real, as Torichelli actually managed to pump the air out of a tube). Thus, via his Discourses, Galileo in reality introduced the engineering approach into physics. Consequently, through the operations of preparing and measurement there appear procedures for the material realization of ideal elements. In addition to this, Galileo was the first to achieve success by making an observation objective, thus giving rise to the modern physical experiment. Experimentation and measurements are thus separated from the individual scientist and whatever sensations he or she may have is transformed to a description of procedures. Only such an objective approach to experimentation allows us to use different devices to amplify our knowledge, in the same way that mechanical devices (levers, pulleys, etc.) serve to intensify force.
We find this rational and engineering-like creation of the fundamental physical theories in Newton, Maxwell, and the other creators of new branches of physics. (Curiously, though, it remains absent in the accounts of many physicists and philosophers.) It is however a typical trend in physics.  Thus the constructive link within classical mechanics, such as “straight line in motion and force” in Newton’s first law, and “inertial reference system” as Newton’s second law is made. For instance, the definition of the notion of force makes use of the notion of an inertial frame, but how do we actually find such an inertial frame? This is only possible if we independently of the criteria laid down by the Newtonian laws retain some criteria of existence or absence of force or if we find a sufficiently good realization of an inertial frame (e.g., the line: Earth, Sun, system of remote stars represents such attempt).
Theory plays the leading role in the PIO- and SIO-kinds of work and experiment. But there is a third kind of work, namely the experimental study of empirical phenomena X (objects or processes) beyond the region of mental experiments, which is of the form <P| X |M>, where X takes the place of "Theoretical part" in Fig. 1. (There exists a phenomenon X without a sufficiently distinct theoretical model, i.e. SIO).
This kind of work, which is reflected in courses of “General Physics” (by contrast to courses of “Theoretical Physics”) is often seen by many physicists and philosophers (e.g. by empiricists and positivists) as the main or perhaps even the only possible kind of work in physics. Thus, distinguished physicist and educator Richard Feynman in his lectures, ‘The character of Physical Law’ (Feynman 1965), takes a look at the process of the appearance of a law as a “guessing game” (p. 54) or as a “generalization achieved by the human mind” (p. 14). He suggests that from “this idea to look at the thing, to record details and to hope that in the information thus obtained there might lay a clue to one or another theoretical interpretation.” First here, the “true understanding of Nature” begins and that this idea is the key of modern science” (p. 15). 
This view very closely resembles the Duhemiam picture of F. Bacon’s method of generalization by means of empirical induction, which can be described by the following standard sequence:
Empirical facts   Empirical  generalizations   Theoretical laws    (1)
I will call this the “Standard Empirical View”. The majority of philosophical views on science theory are of this empirical kind and derive from the same kind of sequence. “Empiricism has always been a main philosophical guide in the study of nature,” says Bas van Fraassen (van Fraassen 1980, p. 3). In a large time scale, empiricism characterizes the development of science in the following way:
[I]nitially science consists of empirical generalizations formulated by using observation terms. Later, as the science advances, theoretical terms are introduced by definition and theoretical laws or generalizations are formulated in terms of theoretical terms. Thus science proceeds “upward” from particular facts to theoretical generalizations about phenomena, and this upward process proceeds in an essentially Baconian fashion. (Suppe 1974, p. 15).
Thus, we can discern two kinds of laws: empirical laws and theoretical laws. The classical example of the Baconian process of arriving at an empirical law by empirical generalization is Boyle’s law for an ideal gas. But since such an empirical law claims universal validity, it becomes exposed to Hume’s problem. Why don’t scientists, then, take notice of this problem? I think that one should employ “Galileo’s procedure” in physics in this case as well: What is an ideal gas? According to the physical definition, it is a gas, which is subject to the known laws of ideal gases, including the one formulated by Boyle. Otherwise it doesn’t qualify as an ideal gas. (A.J. Ayer pointed this out using as examples the definition of loadstone and the definition of water as H2O as a logical problem (Curd and Cover 1998, p. 812).) This is how the concept of an ideal gas is introduced into thermodynamics in the same manner as Galileo’s vacuum was. The problem lies in its realization, which can be solved by using a sufficiently rarefied gas in the experiment. (In molecular (i.e. statistical) physics, we have another situation, because here an ideal gas is defined by means of its molecular model, but this is another branch of physics.) 
However, we can discern such ‘empirical laws’ from ‘theoretical laws’ (such as Newton’s laws of dynamics or gravitation). The first kind of laws, the empirical ones, operate only with quantities, which can be measured in experiments (e.g. ‘pressure’, ‘volume’, and ‘temperature’), whereas the latter kind, the theoretical laws, make use of new ‘theoretical’ entities (e.g. ‘force of gravitation’, and ‘mass’), which are absent in, for instance, the empirical data of Tycho Brahe and the generalizations (empirical laws) discovered by Kepler. 
One of the problems often discussed in philosophy of science is the question “What sort of things laws are?” (Curd and Cover 1998, p. 805). M. Curd and J.A. Cover discuss “two important and influential ways of understanding law – the regularity approach and the necessitarian approach.” The first way to conceive of laws is represented by A.J. Ayer and conceives of laws as ‘generalisation about events’ (Curd and Cover 1998, p. 806), while the second way, represented by F. Dretske, connects laws to a ‘relationship between properties or magnitudes’ and the modality ‘must’ (“Laws tell us what… must happen”) (Curd and Cover 1998, p. 838). At this point, I should mention that this discussion concerns a very difficult logical question: What is the logical status of a ‘law of nature’? My claim, on the other hand, concerns the physical status of laws in physics, and it basically says that physical laws determine a number of quantitative relations which hold between  qualities of objects and processes. ‘Generalization’ thus becomes close to being the description of the central process of deriving empirical laws (but one should note that in order to transform a hypothesis formed on the basis of Bacon's way of ‘generalizing into a law’, it is necessary to add to this Galileo’s procedure). ‘Necessity’ then – as opposed to ‘generalization’ – can be used in the cases concerning ‘theoretical’ laws, which are elements of an NBP and the result of PIO-kind of work.
The existence of two (PIO- and SIO-)levels in the PIO-view renders a number of difficult questions superfluous. Thus, for instance, it avoids N. Cartwright’s problem that truth and explanation exclude each other and that fundamental Laws of Nature do not describe “facts about reality” (Curd and Cover 1998, p. 866). The point is that while the PIO belongs to some definite branch of physics, the SIO can be built using PIOs from different branches of physics. The motion of a charged body (with gravitational mass),  for instance, can be described using PIOs from mechanics plus gravitation theory and electrodynamics.  This is discussed by N. Cartwright as a “composite case” from a Laws of Nature point of view (Curd and Cover 1998, p. 865-877): “We explain certain complex phenomena to be the result of the interplay of simple, fundamental laws,” she says (Curd and Cover 1998, p. 875). However, she faces a problem in this composite case. This is because, according to her, “gravitation and electric forces are both produced, yet neither exist,” since “no charged object will behave just as the law of universal gravitation says; and any massive object will constitute a counter example to Coulomb’s law…  In order to be true in the composite case, the law must describe one effect (the effect which actually happens); but to be explanatory, it must describe another” (Curd and Cover 1998, pp. 870, 868, 869).
How does this problem, then, come into view in the theoretical physics PIO-view? First of all, according to the PIO-view, complex phenomena are considered to be the result of the compositions of PIOs (in an SIO), not “of the interplay of laws” (theoretical laws in N. Cartwright’s examples). Thus, with regard to the first part of Cartwright’s claim, her laws are to be replaced by SIOs. According to the PIO-view, “theoretical” laws of nature describe PIOs, which are in one sense real, yet in another artificial. Every law and every PIO thus belongs to only one branch of physics (this, by the way, is the reason why Cartwright’s example of the SIO-like massive charged objects cannot “constitute a counter example to Coulomb’s law”). The laws Cartwright lays out as different parts of her claim (“fundamental” and “explanatory” laws) are in fact different entities, which belong to different levels: to the SIO-level, and to the PIO-level, respectively. Since she mixes them up, she ends up with a paradox, which physicists needn’t bother with.
5. The Role of Measurement in Physics
The “[g]eneral positivist view that what can’t be seen can’t be” (Needham 2004) leads to the “Observational-Theoretical Term Distinction” of the Received View and to B. van Fraassen’s empiricist “observable – non-observable” distinction. These distinctions are considered to be one of the central points of contemporary philosophy of science. But what precisely one should count as “observable”, is not at all clear (much debate, for instance, therefore surrounds questions concerning whether such objects as paramecia or mitochondria should be counted as observable or not (see Suppe 1974, pp. 80-85; Alspector-Kelly 2004). According to my “theoretical physics primary ideal object” view, there is yet another distinction to be made: namely that between the “theoretical” part and the operations of measurement (and preparation). 
Thus, instead of having to rely on the vague concept “observable”, one is able to use the much clearer concepts “preparable” and “measurable”, i.e. concepts of “measurable quantity” or “measurability” (as, for instance, a distinctive trait of a system or its states), which are based on a distinct standard associated with operations of comparison to it, as well as clear operations of preparation of a physical system and its states. As such, for example, an electron is “unobservable”, yet it is still “preparable”. In addition, all of its distinctive traits (including such unclassical characteristics as, for instance, spin) are “measurable”, whereas they would be highly questionable, were they conceived of as “observable”. I wwould like to stress the fact that for some quantities (such as magnetic fields in electrodynamical theory or “charms” in quark-theory), it is doubtful if they are indeed “observable”. Nevertheless, they are surely “measurable”. 
There exist different kinds of measurable values. One of these kinds, exemplified by position and velocity in classical mechanics, exists external to the NBP, i.e. is imported from outside it. There exists the problem of accuracy of standards, e.g. dependence from temperature, and so on. This problem is a subject of present-day physical theories, but is really external to Newtonian mechanics. There are theories imported from the outside which are not questioned within the frames of Newtonian mechanics itself. In Newtonian mechanics there exists the problem of the inertial frame, but this doesn’t mean that there are any internal problems concerning measurements of position, time, and velocity within Newtonian mechanics. The imports influence the theoretical part but are not influenced by the latter. The other part, including such entities as mass and force in classical mechanics, and spine in quantum mechanics, has an existence internal to the NBP. They influence the theoretical part and are influenced by it in turn. Some of the measurable values, such as position and velocity in classical mechanics, characterize the state of a system; others, such as mass, characterize the system itself. In any case, though, a measurement must be considered a measurement, not an action on a system. The meaning of acting on a system, i.e., to change its state, and of measuring, i.e., exhibiting or visualizing the state, are principally different. Of course one can consider (in a general sense) any complex system consisting of the initial system and a part of the initial measurement device as a ‘test body’. In this case, one ends up with another system and another measurement. One cannot, however, remove the measurement by such procedure at all. (In quantum mechanics one is faced by a similar situation (Klyshko & Lipkine 2000).) 
Thus, in my “theoretical physics primary ideal object” view, the positivist “Theoretical – Observational” distinction is replaced by a new “Theoretical – Operational” distinction, which is one of the characteristic features of the view. What this distinction means is that measurements and preparations are to be considered as special operations that are used (like material for building) to create the NBP and the PIO. 
The role played by measurement postulates in the NBP thus becomes very important. (If, for example, we base our postulates on the solid meter standard and clocks coherent with it, we will arrive at the Galilean transformation rules. If, however, we base our postulates on the ‘solid’ light velocity standard (the 2nd of Einstein’s postulates in his Special Theory of Relativity) and clocks coherent with it (known as ‘light clocks’ constructed from two parallel mirrors and an impulse of light moving between them, sort of like a pendulum) (Feynman, Leighton & Sands 2006), we will arrive at Lorentz’ transformation rules for intervals of time, space, and relativity of simultaneity for different points in space. But the measuring and preparing operations cannot be considered as objects of a physical theory in the same way that phenomena and actions are. The boundary between the central “theoretical” part and the operations is a very important feature of the “Theoretical Physics Primary Ideal Object” View. Such a boundary appears in (Fock 1958, p. 166) as well. It is these operations, which are essential to a kind of experimentation that differentiates present-day natural science from conceptual (i.e. speculative) natural philosophy. Before Galileo, there existed some form of mathematized natural philosophy (paradigmatically expressed in the metaphor of “a book of Nature written in the language of mathematics”), and technical mechanics. Ever since Antiquity, science has concerned itself with natural philosophy, including Aristotelian physics, in the form of descriptions of motion or change. Technical mechanics, on the other hand, has always been concerned with human operations and has thus always belonged to a different world from that of philosophy and science. The operations of preparation and measurement were borrowed from the world of technical mechanics by Galileo (as evidenced by his theory of a falling body as found in his Discourses).  PIO- or SIO conceptual models were materially realized through them. These human operations weren’t to be considered proper phenomena for science. They were very specific elements and there was a principle boundary between these operations and the phenomenon. The latter was considered an object of theory, whereas the operations were not to be, the same way as a man and his operations are not, accordingly, objects of physical theory. Once we take this distinction and accept the heterogeneous (theoretical-operational) character of any description of physical phenomena, many “paradoxes of quantum mechanics” disappear immediately. This distinction between the theoretical and the operational was lost to Laplaceian mechanical natural philosophy, where PIOs have lost their operational parts, and has become elements in a natural philosophy. Informed by such natural philosophy, a transformation of some physical PIOs (like, for instance, field) played a role in the building of models in other sciences. It is important, however, in order to avoid mistakes of Laplace’s type, to be able to discern the difference of meaning of the same term in different contexts. Laplace proclaimed that since all things (including human beings) consist of nothing but atoms, and since atoms can be described by mechanics, then everything can be described by the laws of mechanics. This boundary had no influence on classical physics, but with the creation of a “new” quantum mechanics, the situation changed. I. von Neumann, E. Schrödinger (with his famous “cat”), and others adopted the logic of Laplace’s mechanical natural philosophy (in which quantum mechanics is used instead of Newtonian mechanics). Whilst that boundary was lost to them, they began to see operations of measurements as phenomena and thus as subjects of a theory. Thus, “paradoxes of measurement” appeared that are on our view nonexistent (see Klyshko & Lipkine 2000; Lipkin, 2001b).
6. Different Levels of Conceptual Change in the Natural Sciences and in Kuhn's Model
Though the PIO-view concerns the structure of physical knowledge, it has a number of  consequences for how we view the development of physics and natural science in general. Using Fig. 1 as reference, we can discern 4 levels of Conceptual Change within the Natural Sciences.
The first level is the level of different SIOs. An example of conceptual change on this level is the theory of superconductivity.
The second level is the level of different PIOs, NBPs, and branches of physics, i.e. the different content that fill out the structure depicted in Fig. 1. On this level, the difference between classical and quantum mechanics can serve as an example.
The third level is the level of different sciences or disciplines, i.e. the level of the different structures of the theoretical part of Fig. 1. An example of this kind of conceptual change is the difference between physics and chemistry.
The fourth level is the level of the scientific revolution of the 17th century, where the structure of the NBP conceived as <P| T |M> was born.
On the first two levels, detailed examples can be found in physics. These two levels can be compared to T. Kuhn’s concepts of “normal science” and “scientific revolutions” (Kuhn 1962). 
 The limitation for SIO-type of work, which is that in order to create theories of phenomena. One can only use existing PIOs, resembles Kuhn’s “impression” that research in normal science is not about discovering the unknown, but rather “a strenuous and devoted attempt to force Nature into the conceptual boxes supplied by professional education.” Thus, the first level of the PIO-view is very similar to Kuhn’s conception of “normal science”, and the NBP can be compared to the main part of Kuhn’s “paradigm”. The second level is the level of PIO-type of work under creation of new NBPs which corresponds to creation of new paradigm and Scientific Revolution in Kuhn’s model. These two views are complementary to each other. At the center of Kuhn’s view, there is an interaction of ideas and community which can be applied to a very wide domain. The PIO-view says nothing about a community; it is centered on the structure of physical knowledge and can be applied to some other natural sciences (such as chemistry and synergetics (Lipkin 2001a)). 
It is interesting to note that a consequence of this comparison in the region of physics is a claim to the effect that the main type of work in “normal science” is not solving puzzles but building SIO-models of PIOs, which is like assembling a variety of structures from a small number of details.
Another feature of Kuhn’s model, which should be modified, is his concept of ‘non-cumulativity’. If we take a look at the history of modern physics, we can see that new branches of physics have appeared in three different ways. In the 17th and 18th century, new branches of physics (such as Newtonian mechanics, and hydrodynamics) were created through the process of solving different concrete problems. At the center of these problems was the phenomenon of motion (of a falling body, a planet, or a liquid). In the middle of the 19th century (as evidenced by electrodynamics), new branches of physics were created through the process of trying to create order among the set of known ‘empirical laws’. In the 20th century, new branches of physics (such as the theories of relativity and quantum mechanics) arose from paradoxes. In every case, the different branches of physics are in some sense additive: once an NBP is formed it doesn’t change, and it doesn’t disappear. Revolutions understood as answers to existing paradoxes lead to the creation of new NBPs and branches of physics. Thus, the Special Theory of Relativity (STR) doesn’t eliminate Newtonian mechanics, because their domains only intersect. STR can consider only collision of particles and interaction of charged particles and electromagnetic fields. Many problems typical for Newton mechanics, connected with a variety of forces (e.g. elasticity), fall outside its domain. A similar claim can be made concerning classical and quantum mechanics, and concerning thermodynamics and statistical mechanics.
7. A Composition of Constructivism and Realism in the “Theoretical Physics Primary Ideal Object” View
The PIO view of physics is derived from an analysis of different branches of theoretical physics. It is, as it was shown above through an examination of the PIO-kind of work, a rationalistic approach to physics. (Qua rationalistic it is not disturbed by Hume’s problem, which is one of the most difficult problems for empiricism to cope with.) Furthermore, it is in reality a complex composition consisting of constructivist and realist elements on two levels: the PIO-level and the SIO-level. 
On the PIO-level it may contain realistic (‘Plato-like’) and constructive(ist) modifications. Both are compatible with the PIO-view, but I prefer the latter case. My basic idea is that PIOs are artificial, but real, just like bricks. People make bricks and use them to build buildings, and both bricks and buildings are manufactured, but real. In the case of PIOs and the  theories (theoretical models) built from them, we have a similar situation. PIOs, then, should be likened to Kant’s notion of a priori forms, since there exist no other physical elements except PIOs (this view does not lay far from the view of the Neokantians). Thus, from my point of view, the entities treated by scientific theories do in fact exist in an ontological sense, and the basic ontological elements are real, but artificial PIOs (this also counts for “one-partical” SIOs such as an electron, a proton, or different liquids (see Section 2 above)), and their reality is guaranteed by the operations of preparation and measurement. Thus, there exists a constructivist (but not conventional) kind of work on the PIO-level (in periods of “scientific revolutions”) and realistic on the SIO-level (in periods of “normal scientific conduct”).
However, the constructivist view lead to a difficult question concerning the intersection between the ‘historical time’ where theories, PIOs and their creators are born and become alive in some culture, and the ‘time of trajectories’, which is connected to physical dynamics. The latter kind is unhistorical in essence. According to classical mechanics, when a body moves through space and in time, time stretches toward infinity in both directions. The concept of time in classical mechanics is “the time of Kant’s phenomenal world”, where no such things as freedom, creativity, and history exist. That’s why, according to the ‘time of trajectories’ of physics, all PIOs are considered to be existing always. In PIO-constructivism we suppose that PIOs are a priori forms, which can be used to transform Chaos into Cosmos, i.e. Nature can be ordered by physics. Physical cosmological models like the ‘Big Bang Model’ are attempts of the same kind, although with more complex physical ordering, including process ordering. Thus, in cultural history, i.e. in historical time, modern physics appeared in European modern culture as a cultural phenomenon with an unhistorical internal structure. Therefore, the answer to questions like “Was there electromagnetic field before electrodynamics theory?” in historical time must be negative: The phenomenon that we call an electromagnetic field only emerged out of Chaos with the birth of electrodynamical theory. And in the unhistorical ‘time of trajectories’, we should essentially ignore this kind of historical question as a wrong question to ask in the context of physics. Such historical questions fit harmoniously within, for instance, Laplace’s Picture of the Universe, founded in natural philosophy, but the latter is rejected by the philosophy of science of the 20th century (although it is still popular among physicists).
8. Conclusion
Thus, the “theoretical physics primary ideal object” view gives new structure to physical knowledge, which it sees as organized in new units – branches of physics -  each of which has its own foundations integrated in a heterogeneous theoretic-operational “nuclear of branch of physics” (NBP), complete with its own “primary ideal objects” (PIOs). The core of any theory is its physical model. This structure has two main levels, which correspond to Kuhn’s levels of “scientific revolution” and “normal science”.
Though the two models are devoted to different aspects, the PIO-model speaks only about the structure of physical knowledge (and tells us nothing about interaction of ideas and people), they do share some common ground in physics. That is why a comparison of these two complementary models lets us make some interesting adjustments to Kuhn’s model. The PIO-view opens up the opportunity for us to give new answers to a great deal of questions in philosophy of science concerning measurement. Instead of the vague notion “observable”, one is here in possession of  a clear concept of “measurable quantity” (“measurability”), which is based on a distinct standard and operations of comparison associated with clear operations of preparing of physical system and its states for measurement. In comparison with the view of van Frassen, this view furthermore gives us new answers to the debate between realism and constructivism: It is constructivist on the PIO-level and realistic on the SIO-level, and it throws new light on the status of laws of nature.
Acknowledgements
This article is the outcome of a number of projects supported by The Fulbright Grant and by the Russian Foundation for Fundamental Research.
References
Alspector-Kelly, M. (2004): “Seeing the Unobservable: Van Frassen and the Limits of Experience”. In: Synthese 140(3): 331-53
Curd, M. and J.A. Cover (eds.) (1998): Philosophy of Science. The Central Issues. New York and London: W.W. Norton & Co.
Einstein, A. (1949), in: Albert Einstein Philosopher-Scientist (Evanston)
EINSTEIN A. (1949) in: Albert Einstein: Philosopher-Scientist (Evanston).
FEYNMAN, R. (1965) The Character of Physical Law (Cambr., London).
FEYNMAN, R.P., LEIGHTON. R.B., SANDS, M. (2006) The Feynman lectures on physics in 3 vol. (San Francisco)
FOCK, V.A. (1958) Criticism of Bohr's outlook on quantum mechanics, in: Philosophical Problems of Modern Physics (Moscow)
FRAASSEN, van B. C. (1980) The Scientific Image. (Oxf.).
GALILEI G. Discorsi e demonstrazioni matematiche, intorno 'a due nuoe scienze Attenti alla Mecanica \& Moviment i Locali, In: Galileo Galiley Opere (Salany editore, Vol. 4).
GALILEI, G. (1909) Discorsi e demonstrazioni matematiche, intorno 'a due nuoe scienze Attenti alla Mecanica & Movimenti Locali in: Opere (Fienze)
GIERE, R. (2004) How Models Are Used to Represent Reality, in Philosophy of Science. Proceedings of the 2002 Biennal meeting of the Philosophy of Science Association, v. 71, N 5, pp. 742-752.
HEISENBERG, W. (1969) In: Properties of mater under unusual conditions. Interscience, (N.Y.-L.), pp. 7-10.
HUTTEN, E.H. (1953-54) The Role of Models in Physics, in: British Journal for the Philosophy of Science, 4, pp. 285-301 .
KLYSHKO, D.N. , LIPKINE A.I. (2000) About the "reduction of wave function", quantum theory of measurement, and incomprehension' of quantum mechanics, in: "Electronic Journal "Investigated in Russia", 53е, p. 703-735 
http://zhurnal.ape.relarn.ru/articles/2000/053e.pdf 
KUHN, T. (1962) The Structure of Scientific Revolutions (Chicago)
LANDAU, L.D., LIFSHITZ, E.M. (1977) Course of Theoretical Physics V. 1-10.
LIPKIN, A.I. (2001 a) Foundations of Modern Natural Science. Model View on Physics, Synergetics, Chemistry (Moscow).
LIPKIN, A.I. (2001 b) Does the wave function reduction phenomenon occur in quantum measurement? In Physics-Uspekhi, Vol. 44 (4), 417-421.
MANDLSTAM, L.I. (1972) Lestures on optics, theory of relativity, and quantum mechanics. Moscow.
Needham, P. (2004) When did atoms begin to do any explanatory work in chemistry?, in: International Studies in the Philosophy of Science, 18, Numbers 2-3, pp. 199 – 219.
STACHEL, J. (199(5)) Feynman Paths and Quantum Entanglement: Is There any More Mystery?, in: Potentiality, Entanglement, and Passion-at-a-distance (quantum mechanical studies for Abner Shimony, vol. 2) (Dordrecht/Boston/London). 
SUPPE, F. (1974) The Search for Philosophic Understanding of Scientific Theories, in The Structure of Scientific Theories (Edited with a Critical Introduction by Frederick Suppe) (Urbana, Chicago, London), pp. 3-241.
SUPPES, P. (1969) Studies in the Methodology and Foundations of Sciences (Selected papers from 1951 to 1969) (Dordrecht, Reidel).
WARTOFSKY, M.W. (1979) Models. Representation and the Scientific Understanding (Dordrecht, Boston, London).