p The presence of materialist dialectics in the theoretical content of modern physics discussed in the preceding chapters is now an unquestionable fact. This applies not only to the results obtained by physics, which confirm the principles of dialectics, but also to the process of obtaining these results, to theoretical thinking of scientists. That this is the situation follows not only from the research into the philosophical problems of science by conscious adherents of dialectical materialism, but also from analysis of the works of the scientists who created and developed modern physical theories, including ones whose personal philosophical views do not coincide with the propositions of Marxist-Leninist philosophy.

p That dialectics as a method and philosophy of science is not something external to modern physics but is born, so to say, within it, makes the latter dissimilar in a certain sense from the old, or classical physics. It does not, however, follow from this that classical physics was metaphysical in character. We would like to draw attention here simply to the following feature of the historical development of physical science: classical physics was satisfied in its day to recognise certain fixed schemes and stable fundamental concepts (Newton’s conception of space— time—mass—force; the constant atoms), whereas modern physics excludes immovable schemes and eternal basic principles from the start. The state of the science in the 120 past, above all of physics, encouraged to a certain extent the predominance of a metaphysical way of thinking among scientists of the eighteenth and nineteenth centuries, although science had already by then demonstrated by discoveries and the accumulated facts that everything in nature happens in the end dialectically. From that angle, it seems to us that Engels’ words about the conflict between the results obtained by science and scientists’ preconceived mode of thinking, which explained the confusion in theoretical science in the nineteenth century,^^1^^ apply to twentieth century science with major reservations.

p Dialectical contradictions permeate modern physics, including its holy of holies, its theoretical foundations. The law of the unity and struggle of opposites makes it possible to express the change and development of objectively real nature in the logic of concepts. Development as a unity of opposites is a splitting of the whole into mutually exclusive opposites (aspects, tendencies), and the relationship between these. This applies to all the phenomena and processes of the material world, and to their reflections in the form of concepts in the human brain, i.e. to their cognition.

p If we take physical knowledge as knowledge abstracted from its origin, movement, and development, it appears to be deductive knowledge. In that case, it is usually (when physics is considered as theoretical physics) in the form of a deductive theoretical system (or several deductive systems), e.g. classical mechanics, thermodynamics, relativistic mechanics, quantum mechanics. The laws of formal logic (traditional or modern) are then sufficient to solve the problems of cognition relating to physics that arise.

p If, on the other hand, we take physical knowledge as it exists in reality, i.e. from the point of view of its origin (from experience) and development, then formal logic proves to be limited when used to solve cognitive problems. Such physical knowledge already appears as a succession of theories, as the emergence of a new theory, with new principles and basic concepts, from an old one. Here materialist dialectics comes on the scene as dialectical logic, which is concerned with developing knowledge and the laws of development of scientific cognition.

p From this point of view a proposition (let us take a nonphysical example: ’the house exists’) and its negation 121 (’the house does not exist’) cannot be regarded as true in one and the same theoretical system, i.e. a proposition and its negation cannot be proved in it; they can have, so to say, only parallel existence; they coexist in different theoretical systems. This circumstance is expressed in formal logic in its most general and complete form by the law of contradiction, by which a proposition and its negation in a formal or formalised theoretical system cannot be true simultaneously; in other words, the opposition between them is absolute (in our example of a house this means that the statement ’the house exists’ and its negation ’the house does not exist’ cannot be regarded as true at the same time in one and the same theoretical system if one has one and the same house in mind at one and the same time).

p This is not the place to enlarge on the subject of formal logic’s serving the cognition of truth when it is not called on to perform tasks not proper to it.  [121•*  From the angle of the formal-logical system the elements of stability in connections and transitions that are united in the objective world by diverse relations between developing things are fixed (conditionally). Dialectical logic points out the relative nature of the abstract isolating lines; by assuming the existence of the limits to the applicability for established concepts, principles, and theories, it unites various, opposite concepts, principles, and theories through mediating logical links in higher synthetic constructions.

p It is important to note, for the theme of this chapter, that dialectical logic does not merely reject the absolute significance of the opposition between a statement and its negation. It preserves the actual content of this opposition as an absolute value within certain limits, which are determined by the conditions in which a certain theory is applicable, but the opposition becomes relative beyond these limits. It is this kind of ‘maintenance’ of the value of concepts, and not some other kind, that ensures, on the one hand, precision of the language of concepts employed and, on the 122 other hand, gives these concepts the flexibility needed when science embraces a wider circle of phenomena that the existing theory cannot explain.  [122•* 

p In our view this is the most important feature of the dialectics and logic that guided Marx in Capital and brought brilliant results to science. In this connection suffice it to recall his reasoning, say, about how the transformation of money into capital is disclosed on the basis of the immanent laws of the exchange of commodities, and the moneyowner is turned into a capitalist; the role of such a special commodity as labour power (a use value that has the property of being a source of value) in this transformation brought out by Marx, and of the various historical conditions that must be met for the money-owner to be able to find labour power on the market as a commodity. Marx’s thought, formulated in the course of the reasoning, to wit, ’it is therefore impossible for capital to be produced by circulation, and it is equally impossible for it to originate apart from circulation. It must have its origin both in circulation and yet not in circulation’^^2^^, opened the necessary perspectives for understanding the logic of the solution of the problem.

The analysis of corresponding points of a logical character bearing on Marx’s argument has introduced the term ’ antinomy problem’ into Marxist literature.^^3^^ We will not go into these topics here, however, though they are very important and interesting for dialectics, and refer the reader to the available literature. Our brief remarks about dialectical contradiction should help towards a clearer understanding of the logical essence and conceptual language of the theory of relativity and quantum mechanics, which developed from classical physics. We shall try to show that the idea of dialectical contradiction, and only it, made it possible to construct the theory of relativity and quantum mechanics in the forms now known, in which they work fruitfully.