Review Article
Quantum Mechanics proof of dialectics, denial of positivism

Dialectics in Modern Physics, by M.E. Omelyanovsky, Progress Publishers, 1979. £1.50 from Labour Review, Vol. IV No. 3, August 1980.

Engels’ classic Dialectics of Nature was written at a time when most branches of science had only begun their development. Engels showed that it was dialectical Nature which was reflected in dialectical thought. He established the vital role of natural science in the development of a scientific world outlook – dialectical materialism.

The revolution in physics which took place at the turn of the century was grasped by Lenin in his Materialism and Empirio-criticism, written just as the shock waves of the discoveries in micro-physics were being felt. Lenin combated trends of revisionism and reactionary philosophy that sought to distort the significance of these discoveries. He showed that natural science deepened and strengthened dialectical materialism.

The nationalised property relations established by the October Revolution unleashed enormous forces for natural scientific development guided by and enriching Marxist philosophy. The early, extremely exciting developments arising from this were stifled and distorted by Stalinism. The Bolshevik scientists were liquidated during the period of the Moscow Trials. Internationally, the impact of Marxism on the sciences was poisoned by bureaucratic dogmatism.

Despite this, the molecular developments taking place on the basis of the gains of the October Revolution, under conditions where several generations of young scientists were trained to begin from the methodology of dialectical materialism, have recently produced an outstanding series of books which must be compulsory reading for all revolutionaries.

Dialectics in Modem Physics by M.E. Omelyanovsky is the best of the series. This book continues the work of Engels’ and Lenin’s classics with 70 years of scientific development sublated into it. The powerful achievements of Soviet ·and bourgeois science over this period have made possible the clarification and concretisation of the concepts and principles of dialectical materialism, with all the rigour and discipline that Nature imposes on the natural sciences. Dialectics in Modern Physics brings together, in a coherent whole, the most significant conclusions of Soviet scientific philosophers. Subjects discussed include objective reality, cognition, relative and absolute, the emergence of a new theory out of the crisis of the old, probability and possibility as objective moments of the movement of matter, whole and part (system and element); also, initially more specifically natural scientific problems such as observability, visualisation, particle-wave duality, determinism, measurement and invariance principles and transformation.

Formal logic, the logic of relationships between fixed categories, guided the growth of natural science from its beginnings. During the period of the empirical gathering of sensuous knowledge, and analysis of this material on the basis of Newton’s (classical) mechanics, formal logic was adequate, and, in distinction to the vague dialectics of the Greeks, played a necessary, progressive role. As Hegel’s cutting critique of contemporary science, 150 years ago, showed however, this material had already revealed the higher, more flexible logic of dialectics.

Classical physics rested on three apparently unshakeable pillars – Newton’s (particle) mechanics, Maxwell’s electromagnetic (wave) theory, and the intuitive conceptions of space and time (Galileo’s transformations, Euclid’s geometry, Descartes’ co-ordinate geometry).

Classical mechanics contained the principle of ‘relativity’, since the laws of mechanics were independent of the motion of the frame of reference. Classical electrodynamics however, was not consistent with this principle, as it assumed an ‘ether’ with respect to which the velocity of light would be relative: Maxwell’s equations changed with motion relative to this ether. In 1887, the Michelson-Morley experiment failed to measure the motion of the Earth through the ether. The velocity of light was shown to be the same for any frame of reference, calling into question the existence of the ether. Several attempts were made to modify Maxwell’s equations, or the concept of the ether, to accommodate these observations, but this proved impossible. Einstein postulated instead retaining Maxwell’s equations and extending to them the principle of relativity, the velocity of light being independent of motion of the source. He resolved the resulting contradiction by a radical revision of the intuitive ideas of space and time, and consequently, Newton’s mechanics.

The resulting integrated concept of space-time, which is, moreover, inseparable from matter itself, gave immeasurably greater depth and precision to the understanding of space, time and matter already known in general form to dialectical materialist philosophy.

Einstein’s analysis began from the material practice of the measurement of simultaneity at spatially separate places, by the transmission of electromagnetic waves. Classical theory, confirmed by generations of experience, was contained within the new theory as its limiting case. Conservation of momentum, for instance, was carried over from Newton’s mechanics, through the relativisation of mass, compensating the relativisation of velocity. Science penetrated into the ‘microworld’ through contradictions between classical mechanics, which assumed a continuum in energy, and thermodynamics. Measurements of thermal radiation were found to be explicable only through the adoption of Planck’s hypothesis of discreet energy levels. The particle-wave duality which subsequently emerged defied formal logical analysis. Formal logic was thrown into such a crisis that even the spontaneous materialist outlook of most natural scientists was called into question. As Engels and Lenin pointed out, the crisis can only be resolved through materialism adopting Hegel’s dialectical logic.

By tracing the development of the ideas of the fathers of Modern Physics – Einstein, Bohr, Heisenberg etc. – Omelyanovsky proves that dialectical materialism is the methodology of modern natural science, emerging dialectically, as the objective general laws of the movement of matter, out of the striving of men to grasp nature. A whole spectrum of changing philosophical opinions is expressed by these great bourgeois scientists, the majority of them either ignorant of, or hostile to, dialectical materialism. Despite themselves, however, they have all contributed to the armoury of Marxist philosophy.

One of the important tasks of Lenin’s Materialism and Empiriocriticism was to defend materialism against idealists who said that the new quantum physics of sub-atomic particles proved that matter did not exist. Sensation, they said, did not reflect an external, independently existing material world, but was the product of the mind; men ordered sensations in forms that reflected only their own subjective activity. The same laws of cognition hold in relation to micro-physics as elsewhere. The question is not of the existence of matter, but of elaborating its laws of motion. Nevertheless, it is necessary to understand how the discovery of particle-wave duality was used by subjective idealism.

The early work of the physicists of the Copenhagen school, including Bohr, Born and Heisenberg, tended to support positivism. The principle of ‘uncontrollability of interaction’ and Heisenberg’s ‘uncertainty principle’ were emphasised. It was said that since observation itself influenced the state of a micro-object in an uncontrollable way and since simultaneous determination of all a particle’s properties was essentially impossible beyond a certain limit, then nature ‘in-itself’ was unknowable.

In fact, no revision of the concept of objective reality is necessary. The experimental set-up (means of observation) presupposes interactions of the micro-object which will allow (macroscopic) measurements to be made. Description of the micro-object necessitates relativity with respect to the means of observation, but makes no reference to the mind of any observer. The problem arises because human beings are macro-scopic beings and our sense organs necessarily allow us to perceive directly only macro-scopic events, such as instrument readings. The categories of wave and particle – mutually exclusive phenomena of the macro-world of classical physics- are known to intuitive understanding. The events of the micro-world then, reach our senses, and are cognised, mediated through macroscopic interactions as either wave or particle phenomena. This is the principle of ‘complementarity’, worked out by Bohr. Heisenberg’s uncertainty relation indicates the limit of applicability of the classical wave and particle concepts.

The fact that the outcome of an observation is not the same under the same conditions, but contains possibility as an objective moment of its actualisation is consistent with the dialectical materialist outlook. Einstein, in his discussions with the founders of quantum physics, insisted that this position must reflect incompleteness in the theory. This has not been confirmed by subsequent developments however, and is a vestige of the mechanical conception of matter. Classical statistical thermodynamics accepted probability as an objective factor external to mechanics, and was acceptable to formal logic. The unity of statistical and dynamic law in the very essence of the micro-object was revolutionary however. Niels Bohr, founder of the modern theory of the atom, over the course of his life, definitively broke from positivism and by developing the concepts of complementarity and relativity to means of observation was able to approach a consistently materialist viewpoint. Most of the other important figures also moved in this direction.

It may be helpful to illustrate particle-wave duality with a description of the electron diffraction experiment. (The set-up described is simplified, since the distances involved are extremely small and a practicable experiment would be more complex).

Diffraction of a plane wave through two openings in a barrier may be illustrated as below. Since waves are phenomena known to classical physics, the reader may intuitively understand this as sea waves passing through two openings in a wave-break, spreading into a harbour and disturbing a line of buoys.

Double slit experimental set up

The graph on the right represents light and dark bands on the emulsion after it has been exposed to a burst of electrons. This pattern can in no way be understood as simply the addition of the patterns due to each of two streams of electrons. It can only be explained as the ‘interference’ of wave patterns from the two openings, in phase, due to having the same source. The reinforcement and cancellation of wave trains lead to the bands, whose width depends on the wavelength. Now if the intensity of the stream of electrons is reduced so that specks on the emulsion indicate the impact of individual particles, a paradox arises. The diffraction pattern is built up only by the accumulation of specks. It would appear that each electron passed through both slits and interfered with itself. No other classical explanation is possible. And yet it strikes the emulsion at one localised point.

If we were to place a ‘detector’ near one of the openings to determine which the electron passed through, the uncertainty principle tells us that exactly the impulse required to conclude that the electron passed through one slit and not the other, is just sufficient to destroy the diffraction pattern corresponding to two openings.

Attempts by physicists to construct various ‘models’ consistent with classical concepts, such as ‘wave-packets’, to explain this behaviour invariably fail. The formalism of quantum mechanics, an axiomatised theory, adequately describes this behaviour without any ‘dualism’ or reference to subjective observers. Its interpretation, as a physical theory, requires the understanding of the ‘wave-function’ as a measure of probability, whose only physical manifestation is the appearance of particles. Thus, the micro-object is a dialectical unity of mutually exclusive opposites.

In quantum mechanics, interactions such as those leading to the determination of momentum or position, are represented by corresponding momentum – or position – operators, acting on the wave function, changing its form. When the wave-function has a specific form, in relation to that operator, an eigenfunction, the operator is equivalent to a simply quantity such as classical mechanics uses to represent momentum, position, etc. Otherwise, the operator cannot be reduced in this way. Heisenberg’s uncertainty relation follows from the fact that the wave-function cannot be two different eigenfunctions simultaneously.

The actual wave-function represents the potential possibility for its determination. The correspondence principle by which these operators were developed holds that they bear the same relation to each other as do the corresponding quantities in classical mechanics, showing how Newton’s mechanics was sublated into quantum mechanics.

Another topic given extensive treatment in Dialectics in Modern Physics is the transformations between elementary particles. A whole epoch of classical science was devoted to analysis of substances into their parts, from the discovery of chemical compounds and their analysis into 90-odd elements, to the splitting of the atom into proton, neutron and electron. The discovery that these elementary particles were themselves systems lead to the conclusion that this process would proceed indefinitely, perhaps until a fundamental substance, or ‘building-block’ was found. Not so. These particles are both element and system. Due to the mass-defect, the parts may be, in every way, greater than the whole. It is said to be possible that one electron could contain a whole galaxy.

The problem is not one of an endless series of ‘levels’, but of the discovery of mutual laws of transformation, through corresponding principles of invariance, or symmetry, unity. The actual existence of these elementary particles can only be grasped from the ground of their inter-relation as systems.

To trace the contradictory course of development of these sciences, and of the ideas of the physicists whose life has been identified with these discoveries, is the most valuable lesson in dialectics of all. For, as Omelyanovsky shows, within the confines of a closed physical theory, such as quantum mechanics, formal logic suffices. However, when we take physical knowledge as it exists in reality, developing, transcending and transforming itself through experience, formal logic proves totally moribund, while dialectics proves profound and invaluable.

Further, in this period of this rapid transition from one physical theory to another, only such a methodology can take science forward.

It is at this point that dialectical materialism, as a source of new knowledge, rather than as a dry system of describing what is already known, can be seen to be the only theory able to guide the revolutionary party.

Scientists in the USSR have made an extensive study of the dialectical development of scientific knowledge, and this is one of their most important contributions, increasingly becoming the centre of international scientific discussion. For all those who wish to develop Marxist theory as a weapon guiding the organisation of the struggle for workers’ power and the construction of socialism, this book, and others in the series, makes invaluable reading. The scientific precision of the theory that was necessary to split the atom, must be brought to bear by the revolutionary party in order to unleash the power of the mass movement for the destruction of capitalism. A. B.