A modern dictionary of Catholic terms, both common and obscure. Find accurate definitions of words and phrases.
Anything serving as a subordinate cause. It is a cause that does not begin an action but is applied and directed as a help to its efforts and purpose by the principal agent. An instrumental cause exercises its influence chiefly according to the form and intention of the principal efficient cause. It Catholic theology the role of the priest at Mass and in the administration of the sacraments is that of instrumental cause, used by the principal agent, who is Jesus Christ.
All items in this dictionary are from Fr. John Hardon's Modern Catholic Dictionary, © Eternal Life. Used with permission.