causality(redirected from Unicausality)
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In physics, the requirement that interactions in any space-time region can influence the evolution of the system only at subsequent times; that is, past events are causes of future events, and future events can never be the causes of events in the past. Causality thus depends on time orientability, the possibility of distinguishing past from future. Not all spacetimes are orientable.
The laws of a deterministic theory (for example, classical mechanics) are such that the state of a closed system (for example, the positions and momenta of particles in the system) at one instant determines the state of that system at any future time. Deterministic causality does not necessarily imply practical predictability. It was long implicitly assumed that slight differences in initial conditions would not lead to rapid divergence of later behavior, so that predictability was a consequence of determinism. Behavior in which two particles starting at slightly different positions and velocities diverge rapidly is called chaotic. Such behavior is ubiquitous in nature, and can lead to the practical impossibility of prediction of future states despite the deterministic character of the physical laws. See Chaos
Quantum mechanics is deterministic in the sense that, given the state of a system at one instant, it is possible to calculate later states. However, the situation differs from that in classical mechanics in two fundamental respects. First, conjugate variables, for example, position x and momentum p, cannot be simultaneously determined with complete precision. Second, the state variable &psgr; gives only probabilities that a given eigenstate will be found after the performance of a measurement, and such probabilities are also all that is calculable about a later state &psgr;′ by the deterministic prediction. Despite its probabilistic character, the quantum state still evolves deterministically. However, which eigenvalue (say, of position) will actually be found in a measurement is unpredictable. See Determinism, Eigenvalue (quantum mechanics), Quantum mechanics, Quantum theory of measurement, Uncertainty principle
Nonrelativistic mechanics assumes that causal action can be propagated instantaneously, and thus that an absolute simultaneity is definable. This is not true in special relativity. While the state of a system can still be understood in terms of the positions and momenta of its particles, time order, as well as temporal and spatial length, becomes relative to the observer's frame, and there is no possible choice of simultaneous events in the universe that is the same in all reference frames. Only space-time intervals in a fused “spacetime” are invariant with respect to choice of reference frame. The theory of special relativity thus rejects the possibility of instantaneous causal action. Instead, the existence of a maximum velocity of signal transmission determines which events can causally influence others and which cannot. The investigation of a spacetime with regard to which events can causally influence (signal) other regions and which cannot is known as the study of the causal structure of the spacetime. See Space-time
the genetic link between particular states of the types and forms of matter during its motion and development. The emergence of objects and systems and the alteration of their characteristics (properties) in time have their determining bases in the prior conditions of matter. These bases are called causes; the changes produced by them are called effects.
The problem of causality is directly related to an understanding of the principles of the structure and cognition of the material world. Man’s material and practical activity and the elaboration of scientific predictions are organized on the basis of causality. This accounts for the urgency of the problem of causality in philosophy and in science in general (seeDETERMINISM AND INDETERMINISM). The problem of causality is closely related to the basic question in philosophy: “The subjectivist line on the question of causality is philosophical idealism” (V. I. Lenin, Poln. sobr. soch., 5th ed., vol. 18, p. 159).
The essence of causality is the production of an effect by a cause. Causality is the internal connection between that which already is and that which is generated by it—that which is only becoming. Accordingly, causality differs in principle from other forms of connections, which are characterized by some type of ordered correlation between two phenomena.
Causality is objective; it is an internal relationship inherent in things. It is universal, since there are no phenomena that do not have causes, just as there are no phenomena that do not produce some effect.
The connection between cause and effect is necessary: where a cause is accompanied by suitable conditions, an effect inevitably develops. Given the same conditions, the same effect is always generated by the same cause. The effect produced by a particular cause becomes the cause of another phenomenon, which, in turn, becomes the cause of a third phenomenon, and so forth. This sequence of phenomena linked by the relationship of internal necessity is called a causal or cause-and-effect chain, or a chain of causality. All chains of causality have neither a beginning nor an end. Attempts to find an absolutely “first” or “final” cause entail resorting in one form or another to a miracle or supernatural force.
During the process of causation, matter and motion are transferred from cause to effect. Associated with this is another fundamental feature of causality—the transfer of structure from cause to effect (the reproduction or “representation” of the structure of the cause in the structure of the effect). This is the basis for the property of reflection, which is inherent in matter. All forms of creation, perception, transmission, storage, processing, and utilization of information in technical devices and living organisms are realized on the basis of causal action and the transfer of structure along causal chains. The informational aspect of causation plays an especially important role in society, attaining a supremacy that expresses the essential feature of causality in the social sphere.
The inevitability of the transfer of matter and motion from cause to effect leads to a situation in which the very fact that an effect is generated alters the cause in a specific way. This is a universal property of causality, on the basis of which feedback systems, as well as adaptive systems, emerge during the natural development of matter. The process of causation unfolds sequentially in time. Its starting point is the formation of a cause that will operate (act) under certain conditions. Although the cause precedes the effect in time, there is a more or less prolonged stage when cause and effect coexist and the effect has an active influence on the cause. However, the character of the effect and the precise way in which the cause acts depend not only on the nature of the cause but also on the character of the conditions under which it acts. Conditions independent of the cause of a phenomenon transform into reality the possibility for generating an effect, a possibility contained in the cause.
Substantiation and forms of causality. In dialectical materialism the concept of causality is substantiated on the basis of practice: the fact that man controls specific natural and social processes is decisive proof of the existence of causality.
With the development of practice and cognition, new forms of causality are discovered, which are determined by the character of the corresponding objects and systems and by the form of motion of matter.
Classical physics was based on a mechanistic understanding of causality: a particular initial state of an object and its interactions during the interval of time under observation constitute the cause of the desired state of an object. Predictions of solar and lunar eclipses and the time of the opposition of planets served as an important basis for this conception.
The development of modern physics and especially the development of quantum mechanics led to a substantial modification and generalization of the category of causality. This was associated with the acceptance of the fundamental significance of a new class of theories—statistical theories, the structure of which incorporated concepts of probability. In classical physics it was postulated that all relationships between the properties of an object are quantitatively determined in a rigorous, unambiguous way (Laplacian determinism). However, the structure of statistical theories inevitably includes uncertainties and ambiguities. Thus, for example, in quantum mechanics the definition of a state of a quantum system incorporates the ambiguity of a number of characteristics; therefore, the definition of future states of the system also contains ambiguity. At the same time, the most essential characteristics in the stipulation of states are defined in a completely unambiguous manner.
Cognition of the causes of phenomena is directed primarily at discovering their essence. Of fundamental significance in this regard is F. Engels’ idea that it is meaningless to insist on the absolutely exhaustive cognition of all the cause-and-effect connections of an object (K. Marx and F. Engels, Soch., 2nd ed., vol. 20, p. 534). Within the framework of statistical theories, and especially in quantum mechanics, causality reveals precisely those essential interconnections that are defined unambiguously. However, cognition of the causes of phenomena that lead to ambiguous connections goes beyond the framework of these theories.
Philosophical currents that negate or deny causality and determinism have come up with their own explanation for the incorporation of ambiguity and uncertainty in statistical theories. Asserting that these theories provide evidence for a fundamental indeterminism and signify the downfall of the principle of causality, the representatives of positivist philosophy absolutize uncertainty.
The development of the newest generalizations of the category of causality is directly related to the development of new classes of laws—symmetry and control laws. The former express the penetration by cognition of new, fundamental levels of the structure of matter; the latter focus on the discovery of purposefulness and effectiveness in the functioning of complex systems. In the course of this research, the structural and informational aspects of the study of causality have been given priority and have been elaborated.
Causality is only one of the forms of the universal connection between phenomena. V. I. Lenin emphasized that “causality, as usually understood by us, is only a small particle of universal interconnection” (Poln. sobr. soch., 5th ed., vol. 29, p. 144). The laws of nature and society apply to particularly important types of connections. The concept of a “law” is broader than that of “causality.” Causality connects only the cause and its effect, but a law may connect not only a cause with its effect but also, for example, various effects of the same cause or various aspects of the same effect generated by a particular cause.
Causality is never realized in a “pure” form, free of other forms of connection. It can only be separated from them in an abstraction. However, such an abstraction can be extraordinarily productive and effective, because it helps reveal causality as the foundation for the entire system of diverse natural and social phenomena. Of course, once the causal connection has been discovered, one’s thinking should return to the whole picture, and causality should be woven into the complex network of diverse interdependences.
As modern science develops, a growing variety of forms of connection between phenomena is discovered, including relationships that are not directly causal in character. Among some philosophers and scientists, this trend has given rise to the erroneous impression that the study of causal connections and generative relationships has lost importance and is no longer an essential problem in scientific research. Causality, as it were, has ceased to “operate” and yield the necessary results. Thus, the English philosopher and mathematician B. Russell has arrived at a conclusion shared by other philosophers, that “the old” philosophical concept of causality has lost its meaning, and causality actually coincides with any law that permits an inference to be drawn from one group of phenomena concerning another phenomenon (Chelovecheskoe poznanie [Human Knowledge], Moscow, 1957, pp. 362, 486). However, this broad explanation strips causality of its most essential features.
Some conceptions assert the similarity between or even equate causality and fatalism. There are two mutually exclusive purposes for such assertions: the justification of fatalism, or criticism of causality because it leads to or is similar to teleology. Both of these approaches are untenable. In dialectical teaching on causality, phenomena are understood to be necessarily interconnected by their internal nature. In fatalism, however, phenomena in themselves are in no way interconnected; necessity lies beyond them and operates independently of them, governed by some unavoidable supernatural fate. The doctrine of causality does not assert that anything produced by a cause will inevitably occur under all conditions. By changing the conditions, it is possible also to change the effects of a particular cause. By creating conditions under which countervailing causal tendencies develop, it is even possible to interrupt a previously developed course of events, stop the action of a cause, and create new possibilities. By indicating various possibilities, causality provides a real support for human freedom.
The unilinear, mechanistic understanding of causality could not controvert teleology, because it did not accommodate a wide variety of facts. The difficulties of causal explanation resulted in the alternative “either causality or teleology,” which was not surmounted until the theory of causality took as its foundation the idea of the dialectical nature of causality, including the idea of feedback and of purposefulness in the functioning of complex systems. These concepts were further elaborated as general control theory developed. A system is moved to a specific state not by a fictitious “purposeful cause” but by the action of entirely real, specific material factors characteristic of the structure and dynamics of systems with complex organization.
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