In the pilot episode of 30 Rock, NBC executive Jack Donaghy (Alec Baldwin) explains the “three kinds of heat” to Liz Lemon (Tina Fey):
The GE trivection oven cooks perfect food five times faster than a conventional oven because it uses three kinds of heat. Thermal technology for consistent temperature, GE precise air convection technology for optimal air circulation, and microwave technology for incredible speed. With three kinds of heat, you can cook a turkey in twenty-two minutes.
The trivection oven is an actual GE product and Jack’s description is taken nearly verbatim from GE’s website. Jack uses the GE trivection oven as a metaphor to explain the changes he is about to bring to TGS, the show-within-a-show of 30 Rock. Jack explains he is adding Tracy Jordan to the cast, who will be the show’s much needed third source of heat.
The “three kinds of heat” is likely a spoof of something Tina Fey heard an executive say, but it’s an accurate description of what is needed in storytelling. If 30 Rock was only about Liz and Jack there would be something missing—two main characters and their interactions would not be enough to sustain the show. But the third main character, Tracy Jordan, provides a third source of tension and conflict that drives the plot of each episode. Tracy is the third heat, in both the show-within-a-show and 30 Rock itself.
As a general rule (and there are of course exceptions, which you will no doubt look for) when a movie, novel, memoir, or even a short story lacks three sources of heat, the plot feels thin, the pacing slow, or the characters underdeveloped. Either the conflict between the characters is not complex enough to truly complicate the plot and move it forward or the characterization is too thin.
As we will see from the readings this semester, each source of heat is typically a character as in 30 Rock. However, only two of the sources of heat must be characters (as Anton Chekhov argued, every story must be centered around two characters). In “Hills Like White Elephants” the third source of heat is the woman’s unborn fetus. Therefore, the third source of heat simply must be something that complicates the relationship and/or produces tension between the two characters—as the fetus does in Hemmingway’s story. The third source of heat cannot be an abstract concept or intellectual premise though—religion, politics, et cetera. It must be something concrete and specific—the minister at their church, the ballot initiative he supports and she does not.
The “three sources of heat” rule also means that in a short story, it is best to limit the number of primary characters to three. Three characters produce just three relationships that you as the writer must negotiate. Their relationships can be represented by a triangle, where each point of the triangle represents a character. However, the addition of a fourth character produces six relationships you the writer must understand, make distinct, and make play a role in the plot. The number of relationships increases exponentially with each additional character, so a fifth character produces ten relationships, and so on.