Aaron Sorkin characters do not exist in themselves. Their function is to serve as occasions for snappy lines of dialogue. In the last analysis, it does not matter which character delivers which line. All are equally quick-witted, and all speak in two and only two cadences — either sardonic rapid-fire or expansive sermonizing.
Just as lines can land on any character, the cadences can land on any situation. One might think that sardonic rapid-fire is particularly suited for high-stress work situations, but it can work equally well for an elevator ride or a drink after work. Similarly, there is no necessity that expansive sermonizing be reserved for moments that, in our world, would “naturally” lend themselves to leisurely reflection — it can just as easily arrive in the midst of a stressful situation in which every second counts. After all, how will the audience know what’s really at stake in that situation if they are not explicitly told?
The imperative is always: tell, don’t show. Characters exist only in and for dialogue, and this applies equally to what in other shows would be “their own” character traits. We don’t see someone actually being a hard worker or the best in the business or incredibly funny — only an expansive sermon can establish this.
Characters are so radically empty of content, in fact, that we can’t assume anything about them until it’s explicitly stated by the impersonal dialogical stream that flows through the characters. So for example, in many non-Sorkin shows one could take it for granted that a character who has an important job in a competitive field and is played by an African-American man is a “smart black guy” — in the Sorkin universe, however, this must be explicitly stated, preferably by a character who has been previously identified as having some kind of special authority.
At this point, it may seem that the ontological structure of the Sorkin universe is radically indeterminate. Yet there is one fundamental and non-negotiable grid of intelligibility that structures all the relationships that the dialogue establishes. Here it’s particularly important to remember that we can’t rely on appearances — hence we can’t assume that that grid of intelligibility is provided by the workplace setting that is a surface-level feature of all Aaron Sorkin shows. No, the basic structure is that of a family.
The three basic relations available are parent-child, sibling-sibling, and husband-wife. The relationships among the workplace “family” members for the most part share the “always-already” quality of family relationships in our world — main characters have generally known each other since forever. Characters cannot be casual acquaintances or respectful colleagues, nor can they be “just friends” — sibling rivalry is the zero-level. If “new” outside characters are brought in — and as with everything, it must be established through dialogue that the characters have not always known each other, because every character interaction is basically the same regardless of the “history” or level of “comfort” or “familiarity” involved — it is for the sake of exogamy.
It must be said immediately that the lack of “inherent” character traits applies to this schema as well — characters partake of different structures at different times, and indeed “the same” pairing can partake of more than one (Josh and Donna, for instance, are both brother-sister and husband-wife), according to an aleatoric flow — though certain patterns do become more or less firmly established. For instance, once it is determined which character or characters are filling the “father” role, that is never seriously challenged. There is often more than one competitor for the throne, as in the unclear locus of authority between President Bartlet and Leo — but no third contender for the authoritative role ever emerges. (It is worth noting here that the tension between these two was ultimately resolved in President Bartlet’s favor, but only after Sorkin left the show.)
Above all, though, all husband-wife relationships are essentially permanent, whether or not they’ve been “consumated” in the traditional sense. Any dalliance with a person not established as one’s rightful spouse is treated as adultery, forgiving which will serve to establish the moral value of the character cheated upon. And just as God intended, all women are ultimately the “helpmeet” of their work-husband. Their inherent frailty will often lead the work-wife to screw up in some important way, but just as with the case of virtual adultery, such events only serve as occasions to emphasize the magnaminity of the husband/father.
One could criticize Sorkin’s ontology for lacking depth and nuance and view the family structure as artificial and forced, but that is not a flaw so much as the entire point. Every Aaron Sorkin show starts from the same radical subtraction and carries the same basic axioms to the same absolutely rigorous conclusion. Sorkin’s universe is one in which a repeated reassertion of a rudimentary structure is the sole alternative to absolute chaos. Given the absolute lack of inherent “character traits” or “motivations,” their stereotyped relationships are the only thing keeping the “characters” from descending into a total — albeit clever — glossolalia.