I previously asked whether the Trinitarian concept of "3 hypostases" or "3 personae" is the same as "3 persons." This issue is addressed by Trinitarian scholar and
Christian apologist Alister McGrath:
"The word 'person' has changed its meaning since the third century when it began to be used in connection with the 'threefoldness of God'. When we talk about God as a person, we naturally think of God as being one person. But theologians such as Tertullian, writing in the third century, used the word 'person' with a different meaning. The word 'person' originally derives from the Latin word
persona, meaning an actor's face-mask—and, by extension, the role which he takes in a play. By stating that there were three persons but only one God, Tertullian was asserting that all three major roles in the great drama of human redemption are played by the one and the same God. The three great roles in this drama are all played by the same actor: God. Each of these roles may reveal God in a somewhat different way, but it is the same God in every case. So when we talk about God as one person, we mean one person in the modern sense of the word, and when we talk about God as three persons, we mean three persons in the ancient sense of the word. ... Confusing these two senses of the word 'person' inevitably leads to the idea that God is actually a committee.
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