Necessity in Nature

The essential connection and the unalterable trend of development of things, determined by the contradictions within them. To understand necessity in nature, it must be examined in conjunction with chance. Necessity and chance are a pair of categories that reveals the stability and variability of the development of things. Chance is the non-essential connection and the instable phenomenon of the process of development of things. It can occur or not occur, and it can occur this way or that way. For example, it is necessary that you will reap melons, if you sow melons, and that you will reap beans, if you sow beans, because it is determined by the genes of melon and bean; but it is accidental and determined by the combined effects of soil, temperature, rain, and other conditions, when it comes to how many melons are produced by each melon vine and how many pods are produced by each bean seedling.

Democritus in ancient Greece was the first to elaborate necessity and chance. He only acknowledged necessity and held that chance is concocted by man. In modern times, the d’Holbach of France also held that everything we saw was a necessity. Such view of denying chance actually describes chance as necessity, thus reduces necessity to chance. In this regard, Engels pointed out: “If ‘accidents’ played no part, then world history would indeed be a very mysterious nature.” Hegel has elaborated the dialectical relation between necessity and chance, but he regarded the relation between them as a product of the objective spirit. He acknowledged the place of chance in reality, holding that the cause of necessity lies in itself, while chance is conditioned by other things. Hegel also held that necessity can only be grasped through chance. The task of science, especially philosophy, “consists generally in coming to know the necessity that is hidden under the semblance of contingency.” These ideas contain a deep philosophy.

Marxist philosophy upholds the dialectical unity of necessity and chance, holding that necessity and chance are two states that act simultaneously in the interconnection and process of development of objective things. Necessity is the inherent and inner essential connection of things themselves. It determines the basic direction of the development and progress of things; chance refers to the non-essential connection of things, and has an accelerating or retarding influence on the development of things. Necessity can only manifest itself through numerous accidents; chance is the form of appearance and the supplement to necessity. The emergence of a thing or phenomenon is affected not only by essential, necessary causes, but also by accidental, non-essential causes. The difference between necessity and chance is relative. What, at a specific level and in a specific relation, is an accidental connection arising out from non-essential factors can, at another level and in another relation, be a necessary connection determined by essential factors, and vice versa. Necessity opens up its way through chance and manifests itself through complex and diverse accidents, making the process of development of things present a rich and colorful content. Chance implies necessity, and Engels pointed out: “One knows that what is maintained to be necessary is composed of sheer accidents and that the so-called accidental is the form behind which necessity hides itself.” Under certain conditions, necessity and chance can transform into each other. Darwin’s theory of biological evolution proved that in the process of development of biological species, certain features that were accidental for the species at the beginning become fixed and become necessary, and some features that were necessary at first gradually degenerate and lose their necessity when conditions change and appear as accidental features. Engels held: “The Darwinian theory to be demonstrated as the practical proof of Hegel’s account on the inner connection between necessity and chance.” Modern natural science has further revealed the interconnection between necessity and chance. For example, the objects of research of physics (elementary particles, atoms, molecules) have only a small chance of being determined in their position at each given instant. Even so, there is no such thing as pure chance. It is incorrect for metaphysics to divorce the relationship between necessity and chance, or to acknowledge only necessity or only chance, or to treat the two as independent of each other.