Equivalence judgments in exchange require an external third party

Evidence

But there is a more subtle and fundamental way in which the third is necessarily implied in all dyadic contacts, and this is, so to speak, as a medium of exchange. For exchange as such is comprehensible only as a system devised by a third party: for the judgment of identity, the act of setting two different things in equivalence with each other, can only come from the outside. Thus, I exchange a sum of money for an amount of fish: but since these two objects are utterly incommensurate, and since each partner to the exchange sees only his own property (unless he puts himself in the position of a third), the parties to the exchange must of necessity have recourse to some external system of equivalence which fills the function of the third. But inasmuch as all direct contact presupposes a common world of some kind, all such contact must necessarily be mediated by a principle of identity which puts the two freedoms, the two totalizations, in equivalence with each other. Normally, of course, language is itself this third party. (It is in this sense that Sartre’s triadic model is an implicit challenge to structuralism, whose binary oppositions fail to take into account precisely the movement of the exchange itself as a third element, as a mediation.) — Fredric Jameson, Marxism and Form, 490

Categorization

• QUESTION: This exchange-based derivation of the third parallels Marx’s account of the money-form in Capital ch.1 — worth verifying whether Jameson develops that link elsewhere.
• XREF: Strongly resonates with Marx’s analysis in Capital volume 1 of how the money-form emerges from exchange as a third term — and with the reader’s base/superstructure interest. — connects to: Markets can organize exchange without requiring high levels of trust; Mutual trust in iterated exchange is selffulfilling through aligned incentives; Third-party advantage grows as the personal element recedes from exchange — Georg Simmel, The Sociology of Georg Simmel, 4464
• DEEPTHINKING: The claim that all dyadic contact must be mediated by an external equivalence principle — where the ‘third’ is not a person but a systemic position — is a dense, paradigm-level thought about how direct relation is always already structured.

Broader Connections

• Markets can organize exchange without requiring high levels of trust #complicates (0.82)
• Third-party advantage grows as the personal element recedes from exchange #expands (0.78) — Georg Simmel, The Sociology of Georg Simmel, 4464
• Mutual trust in iterated exchange is selffulfilling through aligned incentives #complicates (0.75)