A Model of Path-Dependence in Decisions over Multiple Propositions

Decisions or arguments over multiple interconnected propositions are path-dependent if they depend on the order in which the propositions are considered. I develop a model of sequential decision or argumentation processes over multiple propositions, focussing on so-called modus ponens processes. I prove three main results. (1) Path-dependence occurs if and only if an individual’s or a group’s initial dispositions on a set of propositions violate deductive closure. (2) If we impose universal domain, anonymity and decisiveness on a (collective) modus ponens decision process, path-dependencies are unavoidable. (3) Path-dependence makes sequential decision or argumentation processes vulnerable to manipulation by changes of the decision-path and to manipulation by expression of untruthful views on the propositions. I discuss three escape-routes from the problem of path-dependence: the unanimity approach, the dictatorship approach, and the domain restriction approach.