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F1 reasoning: The Trinity

Reasoning steps: The Trinity

Verdicts: F1 · The Trinity. Shared notes and post-750 development: trinity.

F01.1 (was trinity/T1): One God in three co-equal, consubstantial persons

Step F01.1.1: Scripture

Matt 28:19 (one ’name’ of Father, Son and Spirit); John 1:1 (θεὸς ἦν ὁ λόγος); John 10:30; 2 Cor 13:14; the Spirit as a personal Paraclete (John 14:16, 26).

Step F01.1.2: Patristic evidence

Ignatius (T1) calls Christ ‘God existing in flesh’. Tertullian (T2): ’three … of one substance’. Nicaea: the Son ὁμοούσιος with the Father. The 381 creed: the Spirit ‘with the Father and the Son together is worshipped and glorified’. Sources: ignatius-tri-s1 · tertullian-tri-s1 · nicaea-i-tri-s1 · constantinople-i-tri-s1.

Step F01.1.3: Weighing decision

There is no serious rival reading among the fathers after Nicaea; before it, Tertullian’s ‘degree’ language is subordinationist in wording but defends one substance. Verdict: Trinitarian consensus.

  • Confidence: High.

Step F01.1.4: Source-proximity weighing

  • Scripture (benchmark): The NT names Father, Son and Spirit together as the one God (Matt 28:19; 2 Cor 13:14) and calls the Son θεός (John 1:1; 20:28). The technical terms are later, but the substance is in the text. (Scripture confidence: high)
  • Assessment: Supported at every tier from T1 and by Scripture. All nine traditions confess it classically (Dordrecht I: ‘Father, Son, and Holy Ghost, and in none more’).

F01.2: Are the three persons really distinct (against modalism)?

Step F01.2.1: Scripture

Matt 3:16–17 (the Son baptized, the Spirit descending, the Father speaking); John 14:16 (‘another Helper’); John 17:5, 24 (the Son with the Father before the world); John 1:1 (’the Word was with God’).

Step F01.2.2: Patristic evidence

Tertullian (Era II) against Praxeas, who said ’the Father Himself came down into the Virgin … Himself suffered’: the three are distinct ’not in condition, but in degree; not in substance, but in form … yet of one substance’. Sources: tertullian-f01x-s1 · tertullian-f01x-s2.

Step F01.2.3: Weighing decision

Modalism (Praxeas, Sabellius) was rejected from Era II. Verdict: consensus.

  • Confidence: High.

Step F01.2.4: Source-proximity weighing

  • Scripture (benchmark): The Father, Son and Spirit act distinctly together (Matt 3:16–17) and the Son is ‘with’ God (John 1:1). (Scripture confidence: high)
  • Assessment: Scripture and Era II agree; all nine confess three persons.

F01.2 by tradition

  • Catholic (fathers 4/4; Scripture 4/4): Lateran IV c.1.
  • Orthodox (fathers 4/4; Scripture 4/4): Dositheus 1 (verified).
  • Oriental Orthodox (fathers 4/4; Scripture 4/4): Nerses (verified).
  • Lutheran (fathers 4/4; Scripture 4/4): AC I: ’three persons’ (verified title).
  • Anglican (fathers 4/4; Scripture 4/4): Art. I: ’three Persons’.
  • Presbyterian (fathers 4/4; Scripture 4/4): WCF II.3 (verified).
  • Reformed Baptist (fathers 4/4; Scripture 4/4): 1689 2.3 (verified).
  • General Baptist (fathers 4/4; Scripture 4/4): Athanasian Creed received (Orthodox Creed 38, verified).
  • Anabaptist (fathers 4/4; Scripture 4/4): Dordrecht I (verified).

F01.3: Is the Son eternally begotten of the Father, not made?

Step F01.3.1: Scripture

John 1:1–3 (the Word already ‘was’ in the beginning, and ‘all things were made through him’); John 1:18 (μονογενής, the only-begotten God / Son); Heb 1:2–3 (the Son through whom God made the worlds, the radiance of his glory); John 3:16; Ps 2:7 as read of Christ. Scripture distinguishes the Son as begotten / only-begotten from creatures that are made.

Step F01.3.2: Patristic evidence

Ignatius (Era I): Christ ‘was with the Father before the beginning of time’ (ignatius-f02-s2). Nicaea (325): ‘begotten (γεννηθέντα), not made … of one substance with the Father’ (nicaea-i-tri-s1); the creed anathematizes those who say ‘before he was begotten he was not’ or that ‘he was made of things that were not’ (nicaea-i-f02-s2).

Step F01.3.3: Weighing decision

Reading A (Arian): there was when the Son was not; he is a creature. Reading B: the Son is eternally begotten of the Father, not made. B is chosen. Scripture’s ‘was’ in the beginning and Nicaea’s γεννηθέντα οὐ ποιηθέντα reject A. Complements F01.1–2 (who God is) and F02.2 (the Son’s eternity) by naming the Father–Son relation as eternal generation.

  • Confidence: High.

Step F01.3.4: Source-proximity weighing

  • Scripture (benchmark): John 1:1–3, 1:18; Heb 1:2–3. (Scripture confidence: high)
  • Key sources by tier: Ignatius (T1, w 1.0); Nicaea (T3, w 0.6). Proximity factor: 0.80.
  • Assessment: Era I already places the Son with the Father before time; Nicaea fixes the ‘begotten, not made’ formula against Arius. All nine classic confessions receive it.

F01.3 by tradition

  • Catholic (fathers 4/4; Scripture 4/4): Nicene Creed; Lateran IV: eternally begotten.
  • Orthodox (fathers 4/4; Scripture 4/4): Dositheus 1: ‘begotten of the Father before the ages’ (verified).
  • Oriental Orthodox (fathers 4/4; Scripture 4/4): Nicene Creed (Armenian form).
  • Lutheran (fathers 4/4; Scripture 4/4): AC I (Nicene).
  • Anglican (fathers 4/4; Scripture 4/4): Art. II: ‘begotten from everlasting of the Father’.
  • Presbyterian (fathers 4/4; Scripture 4/4): WCF II.3: ’the Son is eternally begotten of the Father’.
  • Reformed Baptist (fathers 4/4; Scripture 4/4): 1689 2.3 (verified).
  • General Baptist (fathers 4/4; Scripture 4/4): Nicene and Athanasian creeds (Orthodox Creed 38, verified).
  • Anabaptist (fathers 4/4; Scripture 4/4): Dordrecht IV: ‘from everlasting, without beginning of days’ (verified).