Milan Mossé

By issuing requests of one another, we seem to wield what is, on reflection, a remarkable power: to create reasons at will. But how can requesters give us reasons to do what they want, even when they stand in no relation of authority over us? And what would be lost if we saw requests as communicating the existence of pre-existing reasons, rather than creating new ones? I propose that a request creates a reason when and because treating the request as a reason would help the addressee to better comply with a duty to perform acts of the kind requested. I show that this view explains how requests create reasons, why requesting is valuable, and how the reasons created by requests depend on antecedent considerations. I argue, further, that it clarifies the discretionary nature of the reasons created by requests, gives a unified account of how requests create reasons among intimates and strangers, and reveals important forms of unfairness that result from requests.

Algorithms for resolving majority cycles in preference aggregation have been studied extensively in computational social choice. Several sophisticated cycle-resolving methods, including Tideman’s Ranked Pairs, Schulze’s Beat Path, and Heitzig’s River, are refinements of the Split Cycle (SC) method that resolves majority cycles by discarding the weak- est majority victories in each cycle. Recently, Holliday and Pacuit proposed a new refinement of Split Cycle, dubbed Stable Voting, and a simplification thereof, called Simple Stable Voting (SSV). They conjectured that SSV is a refinement of SC whenever no two majority victories are of the same size. In this paper, we prove the conjecture up to 6 alternatives and refute it for more than 6 alternatives. While our proof of the conjecture for up to 5 alternatives uses traditional mathematical reasoning, our 6-alternative proof and 7-alternative counterexample were obtained with the use of SAT solving. The SAT encoding underlying this proof and counterexample is applicable far beyond SC and SSV: it can be used to test properties of any voting method whose choice of winners depends only on the ordering of margins of victory by size.