We take institutions seriously as both a rational response to dilemmas in which agents found themselves and
a frame to which later rational agents adapted their behaviour in turn. Medieval corporate bodies knew that
they needed choice procedures. Although the social choice advances of ancient Greece and Rome were not
rediscovered until the high middle ages, the rational design of choice institutions predated their rediscovery
and took some new paths. Both Ramon Llull (ca 1232-1316) and Nicolaus of Cusa (Cusanus; 1401-64)
made contributions which had been believed to be centuries more recent. Llull promotes the method of
pairwise comparison, and proposes the Copeland rule to select a winner. Cusanus proposes the Borda rule,
which should properly be renamed the Cusanus rule.
Voting might be needed in any institution ruled by more than one person, where decisions could not simply
be handed down from above. Medieval theologians no doubt believed that God’s word was handed down
from above; but they well knew that they often had to decide among rival human interpretations of it. The
Church faced its own decision problem every time a new Pope needed to be elected. Bodies not directly in
the hierarchy of the Church had to evolve their own decision procedures. The chief such bodies were
commercial and urban corporations; religious orders; and universities.
The disagreement between Llull and Cusanus raises the issue: should voting be regarded as a method of
aggregating judgments or as a method of aggregating interests? In the former interpretation (only), voting
procedures are a solution to a problem of approximate reasoning. There is an unknown, true state of affairs
(for medieval thinkers, divine will). A voting procedure aggregates unreliable individual perceptions of the
will of God to a more reliable group judgment of it. In the rougher world of Cusanus, and probably of
electors to the papacy and to Dogeships, only at most lip service is paid to the will of God, and voting is a
process of aggregating interests.