Opposition engenders synthesis

Marginal analysis presumes costs erase benefits and so only what on the margin is uncovered, be it excess cost or excess benefit, factors into the decision-making. The marginal unit is the only determinant of the decision because the infra-marginal units are, as far as the decision-making is concerned, sunk. 

In the dialectic opposites do not erase each other, they excite each other into creative action. Opposition engenders synthesis. In the dialectic nothing is on the margin. Indeed, in the dialectic opposites define each other and bring each other into existence. 

In the biblical scheme of things for the creative process to work properly requires for one side of the dialectic to yield to the other. That is what Shabbos means.