Dialectics is a method of thinking and interpreting the world of both nature and society. It is a way of looking at the universe, which sets out from the axiom that everything is in a constant state of change and flux. But not only that. Dialectics explains that change and motion involve contradiction and can only take place through contradictions. So instead of a smooth, uninterrupted line of progress, we have a line which is interrupted by sudden and explosive periods in which slow, accumulated changes (quantitative change) undergoes a rapid acceleration, in which quantity is transformed into quality. Dialectics is the logic of contradiction.
The laws of dialectics were already worked out in detail by Hegel, in whose writings, however, they appear in a mystified, idealist form. It was Marx and Engels who first gave dialectics a scientific, that is to say, materialist basis. "Hegel wrote before Darwin and before Marx," wrote Trotsky. "Thanks to the powerful impulse given to thought by the French Revolution, Hegel anticipated the general movement of science. But because it was only an anticipation, although by a genius, it received from Hegel an idealistic character. Hegel operated with ideological shadows as the ultimate reality. Marx demonstrated that the movement of these ideological shadows reflected nothing but the movement of material bodies." (18)
In the writings of Hegel there are many striking examples of the law of dialectics drawn from history and nature. But Hegel’s idealism necessarily gave his dialectics a highly abstract, and arbitrary character. In order to make dialectics serve the "Absolute Idea," Hegel was forced to impose a schema upon nature and society, in flat contradiction to the dialectical method itself, which demands that we derive the laws of a given phenomenon from a scrupulously objective study of the subject-matter as Marx did in his Capital. Thus, far from being a mere regurgitation of Hegel’s idealist dialectic arbitrarily foisted on history and society as his critics often assert, Marx’s method was precisely the opposite