atomic doctrine, atomic theory; doctrine concerning the intermittent discrete (granular) structure of material.
Atomism asserts that matter consists of separate and extremely small particles; until the end of the 19th century they were considered to be indivisible. Modern atomism characteristically recognizes not only atoms but also other smaller particles of matter both larger than atoms (for example, molecules) and smaller (for example, atomic nuclei, electrons, and others). From the point of view of modern atomism, electrons are essentially “atoms” of negative electricity, photons are “atoms” of light, and so on. Atomism has also spread to biological phenomena, including the phenomenon of heredity. In a broader sense, atomism is sometimes used to refer to the discrete quality in general of any object, property, or process (for example, social atomism or logical atomism).
Atomism has almost always been stated as a materialistic doctrine. Therefore the struggle concerning it has primarily reflected a struggle between materialism and idealism in science. From ancient times atomism was directed against the idealistic and religious view of the world because it explained all that which exists by means of particles of matter, without having recourse to supernatural causes. The materialistic trend in atomism proceeded from the thesis according to which atoms were material; they existed objectively and could be recognized. The idealistic position was expressed in rejecting the reality of atoms, in declaring them to be only a convenient means of systematization of experiential data (this was the view of the modern doctrine of Machism), and in denying their knowability.
Initially the atomistic views (in the ancient East, in ancient Greece and Rome, and partially in the Middle Ages among the Arabs) were merely an ingenious guess. Later they were transformed into a scientific hypothesis (17th, 18th, and the first two-thirds of the 19th century) and finally into a scientific theory. From its very inception and to the end of the first quarter of the 20th century, the idea of the identity of structure between the macrocosmos and the microcosmos lay at the basis of the atomism. From the directly observable disjunctive quality of the visible macroworld (primarily of the astronomical world) into separate and more or less individually separable parts, the conclusion was drawn that nature, being unified, must be constructed in its smallest part in just the same way as in its largest part. The ancient atomists therefore considered the continuous nature of matter to be only apparent, just as a heap of grain or sand when seen from a distance seems to be continuous, although it consists of a multiplicity of separate tiny particles.
The recognition of the unity of structure between the macrocosmos and microcosmos opened the way to a transference to atoms of such mechanical, physical, or chemical properties and relations as had been revealed among mac-robodies. Proceeding from the predictable theoretical properties of atoms, one could then reach a conclusion concerning the behavior of bodies made up of atoms and then experimentally verify these theoretical conclusions in practice.
The idea of the complete similarity in structure between the macrocosmos and microcosmos had seemingly gained a complete victory after the creation in the beginning of the 20th century of the planetary atomic model, the basis of which was the proposition that an atom is constructed like a miniature solar system. Here the role of the sun is played by the nucleus, and the role of the planets is played by the electrons, which rotate around it in strictly determined orbits. Almost right up to the second quarter of the 20th century the idea of the unified structure of the macrocosmos and microcosmos was understood in a too narrow and too simplified manner, as the complete identity of laws and the complete analogy of structures between the two types of bodies. Hence the microparticles were treated as miniature copies of the macrobodies (as extremely small spheres), moving through exact orbits which were completely analogous to the planetary orbits, with the only difference being that the celestial bodies were connected by the forces of gravitational interaction, whereas the microparticles were connected by the interaction of electricity. Such a form of atomism was called classical atomism.
Modern atomism, which is embodied in quantum mechanics, does not deny the unity of nature between great and small, but it does reveal qualitative differences between microobjects and macroobjects, as follows: microparticles represent the unity of opposite principles of discontinuity and continuity, of particles and waves. These microparticles are not little spheres, as was previously thought, but rather complex material formations in which discreteness (expressed in properties of the particle) is combined in a fixed manner with continuity (expressed in wave properties). Therefore, even the motion of such particles (for example, the electron around the atomic nucleus) proceeds not by analogy with the motion of the planets around the sun (that is, not by strictly determined orbit) but rather by analogy with the motion of a cloud (“electron cloud”), which has diffuse boundaries. Such a form of atomism is called modern (quantum-mechanical) atomism.
Types of atomism’are distinguished by what kinds of specific physical properties are ascribed to the atoms and other particles of matter and by how the forms of motion of the atoms are characterized. In the beginning atomism was particularly abstract and was linked with natural philosophy; to the atoms were ascribed only the most general properties (such as indivisibility, the capability to move and to combine among themselves), which were not connected with any measurable properties of macrobodies.
During the 17th and 18th centuries, when mechanics was being developed, atomism took on a mechanistic character. This kind of atomism was somewhat more concrete than the natural philosophy of the ancients, but it still remained in great measure abstract and had little connection with experimental science. Purely mechanical properties were now assigned to the atoms. The representatives of the “mechanics of contact” school considered that the cause of the joining of atoms was a figure, a geometric form. They attributed to the atoms little hooks, by means of which the atoms attached themselves as it were to each other; sometimes the atoms were described in the form of gears whose teeth approached one another in case of dissolution of bodies or did not approach each other in case of nondissolution (M.V. Lomonosov).The representatives of the “mechanics of forces” (dynamics) school explained the interaction of the atoms by an analogy with gravitational attraction. Here, therefore, only the weight of the particles played a role and not their geometric form (which was accepted to be spherical in shape just as the celestial bodies). A special branch of atomism originated from the dynamics of I. Newton (by the Croatian physicist R. G. Boscovich), in which the idea of G. Leibniz concerning the nonspatial monads (in the form of geometric points—centers of forces) was combined with the concept of “forces” (Newton). This dynamic atomism was the predecessor of modern atomism, in which there is a continuous combination of the concept of the discreteness of matter with the idea of the continuous nature of matter and motion (or “force” in the previous conception). Proceeding from the views of Newton, J. Dalton (1803) created chemical atomism, capable of theoretically generalizing and explaining observed chemical facts and predicting phenomena still not observed experimentally. Dalton attributed to the atoms “atomic weight,” that is, a specific mass which was characteristic of each chemical element. The measure of a chemical element that represented the unity of its qualitative aspect (its chemical individuality) and its quantitative aspect (the value of its “atomic weight”) found expression in “atomic weight.” The development of this idea consequently led to the creation by D. I. Mendeleev of the periodic system of chemical elements (1869–71), which is essentially a junction line of the relations between the measures of chemical elements.
In the middle of the 19th century atomism in chemistry received further refinement in the doctrine of valence (Scottish chemist A S. Couper, the German chemist F. A. Kekulé) and especially in the theory of “chemical structure” (A. M. Butlerov, 1861). Atoms were assigned valence, that is, the ability to combine one, two, and more atoms of hydrogen, the valence of which was set at 1. During the 19th century, entirely new properties, in which were summarized the related chemical and physical discoveries, were attributed to atoms. In connection with the achievements of electrochemistry, electric charges began to be ascribed to atoms (electrochemical theory of the Swedish scientist J. J. Berze-lius); chemical reactions were explained by the interaction of charges. The discovery of the laws of electrolysis by M. Faraday and especially the creation of the theory of electrolytic disassociation by the Swedish scientist S. A. Arrhenius (1887) led to the generalization expressed in the concept of the ion. Ions are fragments of molecules (separate atoms or their groups) bearing electrical charges that have positive or negative whole-number values. The discrete nature of the ion charges led directly to the idea of the discrete nature of electricity itself, which led to the idea of the electron and to the recognition of the divisibility of atoms.
During the second half of the 19th century atomism received a further specific refinement as a molecular physical doctrine, because of the development of the molecular-kinetic theory of gases, which revealed the connection between the thermal and mechanical forms of motion. The basic propositions of the molecular hypothesis arose as early as the 17th (P. Gassendi) and 18th centuries (Lomonosov) but acquired an experimental basis only because of the fact that the law of the volumetric relationships between gases, discovered by J. L. Gay-Lussac (1808), was explained with the aid of the conception of molecules (A. Avogadro, 1811). After that time it was possible to describe a molecule in terms of those physical properties and motions which in their totality would provide values to the macroscopic properties of gas as a whole, such as temperature, pressure, heat capacity, and so on. Subsequently atomism in physics developed into a special branch of statistical physics.
After the discovery of the electron (British physicist J. J. Thomson, 1897), the creation of quantum theory (M. Planck, 1900), and the introduction of the concept of the photon (A. Einstein, 1905), atomism took on the character of a doctrine of physics. Moreover, the idea of discreteness was extended to the sphere of electrical and light phenomena and to the concept of energy, the doctrine of which during the 19th century was based on the concept of the continuity of values and functions of a state. The most important trait of modern atomism consists of atomism of action, connected with the fact that motion, properties, and states of various microobjects may be quantized—that is, they may be expressed in the form of discrete quantities and ratios. As a result, the entire physics of microprocesses, insofar as it is quantum in nature, falls within the field of modern atomism. Planck’s constant (the quantum of action) is the universal physical constant which expresses the quantitative boundary dividing two qualitatively different fields: the macrophenomena and microphenomena of nature. Physical (or quantum electronic) atomism achieved especially great success because of the creation (by N. Bohr, 1913) and subsequent development of the atomic model, which explained the periodic system of the elements from the point of view of physics. The creation of quantum mechanics (L. de Broglie, E. Schrödinger, W. Heisenberg, P. Dirac, and others, 1924–28) gave atomism a quantum-mechanical character. The refinement of atomism was also facilitated by the achievements of nuclear physics, beginning with the discovery of the atomic nucleus (E. Rutherford, 1911) and ending with the discovery of a series of elementary particles, especially the neutron (the British physicist J. Chadwick, 1932), the positron (1932), mesons of various masses, hyperons, and others. In this same period development was proceeding in chemical atomism in the direction of the discovery of particles which are larger than regular molecules (colloidal particles, micelles, macromolecules, particles of high-molecular and high-polymer compounds); this gave to atomism a supermolecular chemical character. In sum it is possible to divide the principal types of atomism with the historical stages in their development as follows: (1) the natural philosophical atomism of ancient times, (2) the mechanical atomism of the 17th and 18th centuries, (3) the chemical atomism of the 19th century, and (4) modern physical atomism.
Major scientific epochs are connected with discoveries in the field of atomism. “With atomic theory a new epoch has begun in chemistry . . . ,” wrote Engels, “and in physics, with the related molecular theory” (The Dialectics of Nature, 1969, p. 257). The revolution in physics at the turn of the 20th century was caused, in V. I. Lenin’s words, “by the most recent discoveries in natural sciences—radium, electrons, the transformation of elements” (Poln. sobr. soch., 5th ed., vol. 23, p. 44). The beginning of the age of atomic energy is directly connected with the subsequent growth of physical atomism.
The achievement of each more profound stage in the cognition of matter and its discrete forms (its structure) has not completed the movement of knowledge into the depths of matter but rather has staked out a surveyor’s mark along this route. “The molecule . . . ,” Engels wrote, “is a ’junction point’ in an infinite series of divisions, a junction point which does not close off this series but does establish a qualitative difference. The atom, which formerly was depicted as the limit of divisibility, is now only a relationship” (K. Marx and F. Engels, Soch., 2nd ed., vol. 31, p. 258). The correlation of atoms and electrons was regarded by Lenin as a concrete definition of the proposition of the unity of the finite and the infinite, where the finite is merely a link in the infinite chain of relations: “Apply to the atoms versus electrons. In general investigate the infinity of matter more profoundly” (Poln. sobr. soch., 5th ed., vol. 29, p. 100).
In order to understand the philosophical aspects of atomism, the distinction made by Engels between the old and the new atomism is extremely important. The old atomism acknowledged the absolute indivisibility and simplicity of the “ultimate” particles of matter; it made no difference whether these particles were considered as atoms of chemical elements (Dalton and other chemists) or particles of prime matter (Boyle and others). The new atomism in fact proceeded from a negation of any sort of “ultimate,” absolutely simple, unchangeable, and indivisible particles or elements of matter. In rejecting the absolute indivisibility or nontransformability of any particle of matter, however small, the new atomism acknowledged the relative stability of a discrete form of matter, its qualitative definitiveness, its relative preservability within well-known boundaries. For example, an atom, which is divisible by certain physical means, is indivisible by chemical means, and in chemical processes it behaves as something whole and indivisible. Exactly the same thing is true of the molecule: divisible (decomposable) chemically into atoms, in thermal motion (up to certain limits when thermal dissociation of matter takes place) it behaves also like something whole and indivisible.
The new atomism has shown that the process of dividing matter has its own numerous boundaries; in such divisions a transition from one stage of the discreteness of matter to another qualitatively different from it is effected. The quantitative operation of division thus leads to a step beyond the boundaries of an existing form of the particle and a transition into the sphere of another one of its forms. In this regard the new atomism opposes, on the one hand, the idea of the absolute divisibility of matter to infinity (Aristotle, R. Descartes, and the dynamists), which represented an example of “inferior infinity” (Hegel), and, on the other hand, the idea of old atomism with its acknowledgment of only one form of particles of matter, by which the process of the division of matter (more exactly its rending apart) would be completed in a single act.
Engels had already indicated the philosophical bases of modern atomism as follows: “The new atomic theory is distinguished from the previous ones in that it . . . does not assert that matter is only discrete, but rather acknowledges that discrete parts of various stages . . . are various junction points, which determine various qualitative forms of existence of universal matter” (The Dialectics of Nature, 1969, p. 257).
Especially important in the new atomism is the acknowledgment of the reversible mutual transformability of any discrete forms of matter and the inexhaustibility of any particle, however small. “Dialectical materialism,” wrote Lenin, “insists on the approximate, relative character of any scientific position concerning the structure of matter and its properties, on the absence of absolute boundaries in nature, on the transformation of matter in motion from one state into another apparently, from our point of view, incompatible with it, and so on” (Poln. sobr. soch., 5th ed., vol. 18, p. 276). An example would be the reversible mutual transformation of a particle of light (photon) and a particle of matter (of a pair—an electron and a positron—in the process of its birth from photons, and its reverse transition into photons during the annihilation of the pair).
The rejection of any sort of ultimate, absolutely unchangeable particles of matter is justified by the entire course of the deepening search of man for knowledge into the structure of matter (V. I. Lenin, Poln. sobr. soch., 5th ed., vol. 18, p. 277).
Where the old atomism proceeded on the assumption that the ultimate, indivisible atoms were located in an external relationship to each other and spatially situated next to each other, then the new atomism acknowledged interrelationships between the particles of matter by which they experienced radical changes, losing their independence and individuality and becoming, as it were, dissolved completely in each other, undergoing the most profound qualitative changes. Thus, an example of an analogous interaction is the reversible transformation of elementary particles of matter.
The inexhaustibility of the electron was clearly revealed after the lack of success in the efforts to construct an atomic model proceeding on the concept of electrons as little spheres (or even points) to which definite masses and charges were attributed and which moved around a nucleus according to the laws of classical mechanics. Rather, nuclear physics has shown that the electron may be born from the neutron, hyperons, and mesons (with the emission of a neutrino); it may be absorbed and disappear as a particle in the atomic nucleus (during electron capture); or it may merge with a positron—that is, it may experience such variegated and complex radical transformations that indisputable witness is borne to its genuine inexhaustibility. In the history of knowledge each major success of atomism has constituted not only a revolution in the physical doctrine concerning matter and its structure but also a defeat in turn for the idealistic view of nature (although in itself atomism, of course, by no means always or in all its concrete forms directly expressed scientific truth). Thus, Dalton’s discovery of the law of simple divisible proportions in chemistry led in the beginning of the 19th century to the defeat of the idealistic theory of dynamism (Kant, Schelling, Hegel, and others), according to which the basis of nature was not made up of matter but rather of discontinuous forces. In physics and chemistry at the end of the 19th century widespread acceptance was gained by the phenomenological, agnostic trend, connected with thermodynamics and most clearly revealed in the energetic world view (W. Ostwald, 1895). Energeti-cism, like Machism, denied the reality of atoms and molecules; it attempted to construct all physics and chemistry on the concept of pure energy, of which a complex of various forms was declared to be matter itself and all of its properties. The successes of physics and chemistry at the turn of the 20th century, especially the calculation of the number of ions—gas particles bearing electric charges—and also the study of Brownian motion indicated the congruence of the values of Avogadro’s number, which had been determined by very different physical methods. In 1908 Ostwald acknowledged his defeat in the struggle against atomism. “I have become convinced that in recent times we have received experimental confirmation of the discontinuous, or granular, character of matter, which has been meticulously investigated by the atomistic hypothesis during the course of centuries and millennia. The isolation and calculation of the number of ions in gases . . . , and also the congruence of the laws of the Brownian motion with the requirements of kinetic theory. . . have now given the most careful scientist the right to speak about the experimental confirmation of the atomistic theory of substance .... Thus the atomistic hypothesis has been raised to the level of a scientifically grounded theory” (Grundriss der allgemeinen Chemie, Leipzig, 1909, pp. iii-iv).
At the end of the first quarter of the 20th century it seemed that electrons ejected during beta decay bore away only part of the energy lost by the nucleus. Hence the conclusion was reached that another part of it had simply been destroyed. The materialistic solution to this difficulty was given by W. Pauli (1931) and consisted in the proposition that together with the electron another, as yet unknown particle of matter with a very small mass and no electrical charge flew out of the nucleus during beta decay. This was given the name “neutrino.” Without the conception of the neutrino it would be impossible to understand many nuclear transformations and also transformations of elementary particles (mesons, nucleons, and hyperons). Thus, here also, the success of atomism inflicted a defeat upon idealism in physics.
After the discovery of the positron, I. and F. Joliot-Curie observed (1933) the transformation of positrons and electrons into photons; they also observed the birth of a pair—an electron and a positron—during the passage of a gamma-ray photon near an atomic nucleus. These phenomena were interpreted as the annihilation (destruction) of matter and as its production from energy. In developing atomism, the materialistic physicists (S. I. Vavilov, F. Joliot-Curie, and others) have proved that in a given case there occurs the reversible transformation of one physical form of matter (substance) into one of its different forms (light). Thus, in this regard, too, atomism by means of its discoveries has dealt a decisive blow to idealism.
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