“Dialectics” is a term used to describe a method of philosophical argument that involves some sort of contradictory process between opposing sides.
In what is perhaps the most classic version of “dialectics”, the ancient Greek philosopher, Plato, for instance, presented his philosophical argument as a back-and-forth dialogue or debate, generally between the character of Socrates, on one side, and some person or group of people to whom Socrates was talking (his interlocutors), on the other.
There are several features of this account that Hegel thinks raise his dialectical method above the arbitrariness of Plato’s dialectics to the level of a genuine science. First, because the determinations in the moment of understanding sublate themselves, Hegel’s dialectics does not require some new idea to show up arbitrarily. Instead, the movement to new determinations is driven by the nature of the earlier determinations.