proprium

Proprium is a Latin term meaning “one’s own” or “proper.” In philosophy, theology, and liturgy, it carries related but distinct senses, all tied to what belongs to a particular thing by nature or designation.

In the scholastic and Aristotelian tradition, proprium designates a property that is proper to a subject and essential to its nature, as opposed to accidents or contingent attributes. It serves to distinguish constitutive traits from attributes that can vary without altering the subject’s identity. The concept is used to discuss what qualities are essential to a thing versus those it can lose or gain without changing what it fundamentally is.

In liturgy, the proper (proprium) refers to the parts of the Mass whose texts change with the calendar, as opposed to the ordinary (ordinarium), which remains constant. Propers include elements such as the Introit, Gradual or Alleluia (or Tract during Lent), Offertory, and Communion, varying according to feast or season. The liturgical system also distinguishes the Proper of Time and the Proper of Saints, depending on the observed day.

In psychology, William James and later thinkers used proprium to denote the self or ego—the center of personal experience and identity from the subject’s point of view. The proprium comprises processes and experiences regarded as belonging to the self rather than to external objects, though the term has fallen out of common use in contemporary psychology.

Overall, proprium retains a core sense of something that is inherent or properly belonging to a given thing, whether as a feature of its nature, a calendar-dependent liturgical text, or a conception of self.