The second basic principle of dialectics is that of development. What it means is that the world is seen not as complexes of ready-made things, but as a complex of processes, in which the things apparently stable go through an uninterrupted change of coming into being and passing away.
The changes going on in the world differ in character and direction. Some of these constitute the movement of bodies in relation to each other; others are changes in the properties, structure and function of an object. Some changes are irreversible (water-ice-water) and others irreversible (embryo-organism). Some processes mean a transition from lower to higher and from simple to complex, and others, from higher to lower, and from complex to simple. Concepts of development, progress and regress are used to designate various types of changes.
Development is a type of motion which involves changes in the inner structure of an object or process. When we say that a system develops, we mean an internal, qualitative transformation of its structure. Structural transformations are irreversible and have a clear-cut direction. Ascendant development towards a higher type of organisation is known as progress, and changes in the opposite direction as regress. Development is a complex dialectical interaction of progress and regress.
Consequently, the world’s motion as a whole cannot be described as development in one direction: either ascendant (progressive) or descendant (regressive). One can speak of change in a certain direction only with regard to individual systems and processes. The correlation between progress and regress differs from one sphere of the material world to another. In inorganic nature, neutral processes prevail (involving both progressive and regressive changes). In animate, organic nature, the main tendency is progressive: towards a more complex internal organisation, structure and functions of living beings. But here, too, progress is combined with elements of regress.
The society develops along the way of progress, although the progress is not straightforward. History has known many reversals and sharp relapses. Nevertheless, its general direction is ascendant and progressive. All successive historical systems are only transitory stages in the endless course of development of human society from the lower to the higher. The highest stage of historical progress, towards which all people are advancing, is the communist society.