In the Objective Story and Subjective Story Throughlines, these same two items are better described as the Catalyst and Inhibitor. Catalyst and Inhibitor act as the accelerator and brake pedal on the forward progress of each throughline. In the Objective Story Throughline, bringing in the Catalyst moves the plot forward more quickly, applying the Inhibitor slows things down. This is a structural aid in pacing a story. In the Subjective Story Throughline, Catalyst and Inhibitor control the rate at which the relationship between Main and Obstacle Characters will develop.
More Catalyst can bring a confrontation to a head, more Inhibitor can delay it.
Because Catalyst, Inhibitor, Range, and counterpoint are all Variations, the proper choice of these items insures that the pacing of the story will seem to come from inside the structure, rather than being arbitrarily imposed by the author. At the Type level, each of the four throughlines has one additional appreciation. It is called a Stipulation, because it stipulates how the growth of each throughline will make itself known. The Stipulation provides a category in which the progress of each throughline can be charted. For example, an Objective Story Stipulation of Obtaining might be seen in the characters gathering cash receipts in their efforts to afford tuition.