the struggle between the two contradictory elements

All processes have a beginning and an end, all processes transform themselves into their opposites. The constancy of all processes is relative, but the mutability manifested in the transformation of one process into another is absolute.

There are two states of motion in all things, that of relative rest and that of conspicuous change. Both are caused by the struggle between the two contradictory elements contained in a thing. When the thing is in the first state of motion, it is undergoing only quantitative and not qualitative change and consequently presents the outward appearance of being at rest. When the thing is in the second state of motion, the quantitative change of the first state has already reached a culminating point and gives rise to the dissolution of the thing as an entity and thereupon a qualitative change ensues, hence the appearance of a conspicuous change. Such unity, solidarity, combination, harmony, balance, stalemate, deadlock, rest, constancy, equilibrium, solidity, attraction, etc., as we see in daily life, are all the appearances of things in the state of quantitative change. On the other hand, the dissolution of unity, that is, the destruction of this solidarity, combination, harmony, balance, stalemate, deadlock, rest, constancy, equilibrium, solidity and attraction, and the change of each into its opposite are all the appearances of things in the state of qualitative change, the transformation of one process into another. Things are constantly transforming themselves from the first into the second state of motion; the struggle of opposites goes on in both states but the contradiction is resolved through the second state. That is why we say that the unity of opposites is conditional, temporary and relative, while the struggle of mutually exclusive opposites is absolute.