Grammatical person, in linguistics, is the grammatical distinction between deictic references to participant(s) in an event; typically the distinction is between the speaker, the addressee, and others. Grammatical person typically defines a language's set of personal pronouns. It also frequently affects verbs, sometimes nouns, and possessive relationships.
In Indo-European languages, first-, second-, and third-person pronouns are typically also marked for singular and plural forms, and sometimes dual form as well (grammatical number). Some languages, especially European ones, distinguish degrees of formality and informality (T-V distinction).
Some other languages use different classifying systems, especially in the plural pronouns. One frequently found difference not present in most Indo-European languages is a contrast between inclusive and exclusive "we": a distinction of first-person plural pronouns between including or excluding the addressee.
A person is a being, such as a human, that has certain capacities or attributes constituting personhood, which in turn is defined differently by different authors in different disciplines, and by different cultures in different times and places. In ancient Rome, the word persona (Latin) or prosopon (πρόσωπον; Greek) originally referred to the masks worn by actors on stage. The various masks represented the various "personae" in the stage play.
The concept of person was developed during the Trinitarian and Christological debates of the 4th and 5th centuries in contrast to the word nature. During the theological debates, some philosophical tools (concepts) were needed so that the debates could be held on common basis to all theological schools. The purpose of the debate was to establish the relation, similarities and differences between the Λóγος/Verbum and God. The philosophical concept of person arose, taking the word "prosopon" (πρόσωπον) from the Greek theatre. Therefore, Christus (the Λóγος/Verbum) and God were defined as different "persons". This concept was applied later to the Holy Ghost, the angels and to all human beings.
In the canon law of the Catholic Church, a person is a subject of certain legal rights and obligations.
The age of reason is the age at which children attain the use of reason and begin to have moral responsibility. On completion of the seventh year a minor is presumed to have the use of reason, but mental retardation or insanity prevent some individuals from ever attaining the use of reason. The term "use of reason" appears in the Code of Canon Law 17 times, but "age of reason" does not appear. However, the term "age of reason" is used in canon law commentaries such as the New Commentary on the Code of Canon Law published by Paulist Press in 2002.
Children who do not have the use of reason and the mentally handicapped are sometimes called "innocents" because of their inability to commit sins: even if their actions are objectively sinful, they sometimes lack capacity for subjective guilt.
In the Eastern Catholic Churches, the Eucharist and Confirmation are given immediately after baptism, even to infants who do not yet have the use of reason. In Latin Rite Catholicism, Confirmation is conferred, except in danger of death, only on persons who have the use of reason; and Holy Communion may be administered to children only if "they have sufficient knowledge and careful preparation so that they understand the mystery of Christ according to their capacity and are able to receive the Body of Christ with faith and devotion." In danger of death, the Eucharist may be administered also to children who lack the use of reason, if the child can distinguish the sacrament from ordinary food and receive it reverently. This is likewise true for those who are not so mentally retarded that they are not assumed to ever gain use of reason.
The concept of hypostasis as the shared existence of spiritual and corporal entities has been used in a number of religious and intellectual settings. The word hypostasis (Greek ὑπόστασις) means underlying state or underlying substance, and is the fundamental reality that supports all else.
In Neoplatonism the hypostasis of the Soul, Intellect (nous) and the One was addressed by Plotinus. In Christian theology, a hypostasis or person is one of the three elements of the Holy Trinity.
Neoplatonists argue that beneath the surface phenomena that present themselves to our senses are three higher spiritual principles or hypostases, each one more sublime than the preceding. For Plotinus, these are the soul, being/intellect (Nous), and the One.
Aristotle used hypostasis in reference to a material substratum underlying change in the unqualified sense of generation and corruption, and otherwise in reference to ousía or substance in a secondary sense for genera and species understood as hylomorphic forms. Primarily, however, he used it with regard to his category of substance, the specimen ("this person" or "this ox") or individual, qua individual, who survives accidental change and in whom the essential properties inhere that define those universals. In contrast, Plato and later Neoplatonism, spoke of the objective reality of a thing or its inner reality (as opposed to outer appearance or illusion). Plotinus taught that God exists in Three Hypostases, The One, The Divine Mind and The Word-Soul. In the Christian Scriptures this seems roughly its meaning at Hebrews 1:3. Allied to this was its use for "basis" or "foundation" and hence also "confidence," e.g., in Hebrews 3:14 and 11:1 and 2 Corinthians 9:4 and 11:17.