A Philosophical and Evidential Defense of the Trinity

By James M. Rochford

Critics of Christianity raise many philosophical or evidential objections against the doctrine of the Trinity. If the critic could show that the Trinity is logically incoherent (like a square-circle or married bachelor), then this would discredit this doctrine. But can the critic demonstrate this? Each objection should be considered carefully.

OBJECTION #1. The term ‘Trinity’ never appears in the Bible.

The Bible never uses this word, but it does teach this concept. How would you describe Captain Ahab in the book Moby Dick? Melville’s biographer described this fictional character as “a brilliant personification of the very essence of fanaticism.”[1] Yet, Melville never uses the word “fanaticism,” and he never describes Ahab as a “fanatic” or “fanatical.”[2] Did this biographer not read Melville’s book? Or did he profoundly misread the character? Of course, these are silly questions for anyone who has read Moby Dick. Melville’s biographer is right: Even though Melville never uses this word, the concept of “fanaticism” accurately captures the main character. The same is true for the doctrine of the Trinity.

It’s fair to say that Scripture teaches the Trinity because this is an accurate deduction of the biblical data. After Judas’ death, we read that Matthias “was added to the eleven apostles” (Acts 1:26). How many apostles were there at this point in history? Would it be fair to say that the Bible teaches that there were twelve apostles? Of course. Eleven plus one is twelve. That’s simple math. But consider Jesus’ statement when he says, “Baptize them in the name of (1) the Father and (2) the Son and (3) the Holy Spirit” (Mt. 28:19). Is it fair to count the names and arrive at the number three? Only a strict hyper-literalist would not allow for such a clear deduction from the text. Indeed, if we don’t allow such simple inferences, then we could no longer interpret the Bible, but only read it.[3]

Many common theological terms do not occur in the Bible. It’s true that the Bible never uses the term “Trinity.” But then again, it also never uses the terms “omnipotent,” “omniscient,” or “omnipresent.” Nor does the Bible use the term “Bible” or the term “Unitarian.” Yet, the concept of the Trinity accurately describes God’s nature. Indeed, the entire field of systematic theology is based on the view that we can establish doctrines based on assimilating the biblical data. Thus, there is nothing abnormal in forming a doctrine by gathering biblical data together like this. Theologians do this all the time.

In fact, Muslim theologians face this same difficulty. In Islam, the doctrine of God is called Tauheed (or Tawhid). This refers to God’s absolute unity and self-reliance. Yet, this term appears nowhere in the Quran. Indeed, it doesn’t appear until years later in the Hadith. Moreover, the central pillar of the Islamic faith is the Shahada. This is the belief that “There is no god but God, and Muhammad is the Messenger of God.” To be sure, these concepts are present in the Quran (see Surah 37:35; 48:29), but these titles and creeds don’t appear until later in Islamic history. The same is true for the Trinity: Later theologians accurately articulated the concepts found in Scripture.

The Trinity is the best explanation for the biblical data. The concept of the Trinity is not a problem for the theologian, but a solution that best explains the teaching of the Bible.[4] Unitarians simply cannot explain the vast number of passages that (1) affirm the deity of the Father, Son, and Spirit and (2) the distinct personhood of each figure. As a case in point, Modalists strongly affirm the first premise, but they deny the second. Arians, however, strongly affirm the second premise, but deny the first. Trinitarians are the only ones who can adequately explain all of the biblical data—not just some of it.

OBJECTION #2. The doctrine of the Trinity was invented at the Council of Chalcedon in AD 451.

At the Council of Chalcedon (AD 451), theologians defined the Trinity as, “God is one nature or essence or substance but three persons.”[5] This has been the standard definition throughout church history. However, this doesn’t mean that these theologians created the doctrine of the Trinity. Instead, they merely articulated the doctrine accurately. To be sure, the early church fathers affirmed all of the propositions that we listed above:

  1. There is only ONE GOD
  2. The Father, Son, and Holy Spirit[6] are all DISTINCT PERSONS
  3. The Father, Son, and Holy Spirit are all TRULY GOD

But affirming these propositions doesn’t bring us to a clear definition of the Trinity. As we have already argued, the doctrine of the Trinity is a solution to these well-supported teachings of Scripture. The early church fathers regularly affirmed the deity of Christ. It took time to articulate how this fit with the other persons of the Trinity, but the doctrine begins to emerge long before Chalcedon (AD 451) or Nicea (AD 325).

Consider one of our earliest extra-biblical sources: Ignatius of Antioch. In ~AD 108, Ignatius wrote about “deceivers” and “Christ-betrayers” who denied the Christian faith. Ignatius affirmed:

  • The deity of Christ. He referred to “Jesus Christ, our God,”[7] “our God, Jesus Christ,”[8] and “God being manifested as a man.”[9]
  • The personhood of the Holy Spirit. These same false teachers deny the existence of the Holy Spirit. He wrote, “As to the Spirit, they do not admit that He exists.”[10]
  • The separate personhood of the Father, Son, and Holy Spirit. He wrote, “[These false teachers] say that the Son is a mere man, and that the Father, Son, and Holy Spirit are but the same person.”[11]
  • The unity of the divine persons. He wrote, “The Holy Spirit does not speak His own things, but those of Christ, and that not from himself, but from the Lord; even as the Lord also announced to us the things that He received from the Father.”[12]

All of the pieces were in place, but the term “Trinity” wasn’t being used yet. However, it wasn’t long before the term appeared in church history. In AD 170, Theophilus of Antioch described the first three days of creation, and he stated that these “are types of the Trinity (triados), of God, and His Word, and His wisdom.”[13]

Tertullian (AD 200) expounded on the concept of the “Trinity” (Latin trinitas).[14] Tertullian writes, “All the Scriptures give clear proof of the Trinity, and it is from these that our principle is deduced… The distinction of the Trinity is quite clearly displayed.”[15] He adds, “The connection of the Father in the Son, and of the Son in the [Advocate], produces three coherent Persons, who are yet distinct One from Another.”[16] Yet he strongly affirmed one God: “That there are two Gods and two Lords, however, is a statement which we will never allow to issue from our mouth.”[17] Tertullian had a highly subordinated view of Christ,[18] but we can see that he was articulating this doctrine long before any church councils appeared.

Clement of Alexandria (AD 200) also wrote about the Trinity: “I understand nothing else than the Holy Trinity to be meant; for the third is the Holy Spirit, and the Son is the second, by whom all things were made according to the will of the Father.”[19]

OBJECTION #3. If the Father is God, the Son is God, and the Holy Spirit is God, then this adds up to three gods—not one. It’s simple math. 1 + 1 + 1 =3. Apparently, Christians do not know how to add.

To begin, this objection makes a category error. It confuses God’s being with his persons. The persons of the Trinity are the same in regard to what they are (i.e. God), but they are distinct in regard to who they are (i.e. persons).

If someone asked me what I am, I would say, “A human being.” But if someone asked me who I am, I would say, “James.” Just imagine if we mixed up these categories. What if someone asked you, “Who are you?” And you said, “A human being.” Such an answer is utterly bizarre because it is confusing categories.

Furthermore, God’s being is a qualitative property—not a quantitative property. That is, you cannot count someone’s being or essence or nature. Think about it like this: If all of the paintings in a museum had the quality of being “beautiful,” we couldn’t ask, “Count how much beauty is in the museum.” This confuses what the paintings are with how many there are. The same is true with God. He is one what but three whos.

Second, this objection commits the logical fallacy of false equivalence. We commit this fallacy when we say that similarities make two subjects the same. For instance, the President is a human being, and I am a human being. But does this mean that I am the President? Surely not. While all three members of the Trinity share the essence of being God, they do not share the identity of being one another.

Third, this objection breaks Leibniz’s Law. Gottfried Leibniz articulated a famous rule of logic called the “Law of the Indiscernibility of Identicals.” The principle states, “If A is identical to B, then any property had by A is also had by B.” Yet, we’ve already shown that God the Father has distinct properties from God the Son. The two are not identical. Therefore, it logically follows that it’s fallacious to equate the two as being the same person.

OBJECTION #4. How can three omnipotent persons exist?

It seems impossible that three omnipotent persons could exist. Yet, the Father, Son, and Spirit all have the attribute of omnipotence. How can these omnipotent persons coexist? And what would happen if these omnipotent persons fought one another? Who would win? Critics claim that such a concept is incoherent.

It isn’t. The persons of the Trinity all have the attribute of omnipotence, but they also possess every other attribute as well (e.g. love, humility, unity, etc.). Love and unity prevent the persons of the Trinity from disunity. Therefore, the persons of the Trinity never contradict each other, but always exist in perfect harmony with one another. Swinburne writes, “The omnipotence of each individual is limited by his perfect goodness, and if one individual has promised the other individual that he will not perform actions…, then his perfect goodness limits his omnipotence so that he does not do such an act. Thus each of two individuals with the earlier divine properties can be omnipotent.”[20]

[1] Emphasis mine. Andrew Delbanco, Melville: His World and Work (New York: Alfred A. Knopf, 2005), 166.

[2] Melville uses the word “fanatic” to describe the captain of the “Jeroboam,” but not Ahab. Herman Melville, Moby Dick: Or The Whale (Scribner, 1902), pp.271-274.

[3] I am indebted to the lectures of Fred Sanders for this insight. See Fred Sanders, “The Triune God.” Zondervan Academic. 2017. Sanders derives this idea from Gregory of Nazianzus.

[4] Greg Koukl, “The Trinity: A Solution, Not a Problem.” Stand to Reason. Published October 30, 2015.

[5] Millard J. Erickson, Making Sense of the Trinity, 3 Crucial Questions (Grand Rapids, MI: Baker Academic, 2000), 52.

[6] One church historian rightly stated that the Holy Spirit is the “forgotten member of the Trinity.” This was especially true in the ante-Nicene fathers. Most of the debates focused on the deity and humanity of Christ. Even today, the Holy Spirit has been largely marginalized. At the same time, the church fathers did affirm the deity of the Holy Spirit. He is called the “Divine Spirit” (Clement of Alexandria, The Instructor Chapter 6),

[7] Ignatius, The Epistle of Ignatius to the Ephesians (Chapter 1, shorter recension).

[8] Ignatius, The Epistle of Ignatius to the Ephesians (Chapter 18, shorter recension).

[9] Ignatius, The Epistle of Ignatius to the Ephesians (Chapter 19, middle recension).

[10] Ignatius, The Epistle of Ignatius to the Trallians (Chapter 6, middle recension).

[11] Ignatius, The Epistle of Ignatius to the Trallians (Chapter 6, middle recension).

[12] Ignatius, The Epistle of Ignatius to the Ephesians (Chapter 9, middle recension).

[13] Theophilus of Antioch, To Autolycus 2:15.

[14] Tertullian, Against Praxeas, 2.4.

[15] Tertullian, Against Praxeas, 11.

[16] Tertullian, Against Praxeas, 25.

[17] Tertullian, Against Praxeas, 13.6.

[18] Tertullian’s view was helpful. Yet, it “involved an unwarranted subordination of the Son to the Father.” Origen went further by saying that Jesus was subordinated “in respect to essence, and that the Holy Spirit is subordinate even to the Son.” L. Berkhof, Systematic Theology (Grand Rapids, MI: Wm. B. Eerdmans publishing co., 1938), 82.

[19] Clement of Alexandria, Stromata, Book 5, ch.14.

[20] Richard Swinburne in Thomas McCall and Michael Rea (general editors), Philosophical & Theological Essays on the Trinity (Oxford University Press, 2009), 22-23.