The Singular Function of Money: Medium of Exchange as the Constitutive Principle, with Implications for the Monetary Status of Bitcoin

This paper argues that money possesses exactly one constitutive function—that of a medium of exchange—and that the two remaining functions of the standard textbook triad (unit of account and store of value) are, respectively, a logical prerequisite and a temporal consequence of that singular function. The paper's principal contribution is the identification of a strict hierarchical structure—precondition → constitutive function → accidental property—that replaces the conventional coordinate triad with a precise logical architecture. A differentiating criterion is introduced: a constitutive function must distinguish the kind in question from other kinds; since many non-monetary goods store value, value-storage cannot be constitutive of money. An infinitesimal time argument (Δt > 0 between all transactions) formalizes the derivative status of value-storage. The Keynesian construct of liquidity preference is reinterpreted as a change in the temporal profile of exchange under uncertainty. Applied to Bitcoin, the framework reconciles it with Mises's regression theorem by identifying permissionless settlement as pre-monetary use-value. The dominant "digital gold" narrative is shown to be theoretically incomplete without grounding in exchange functionality.