Are there published testimonies from Christians who independently discovered the doctrine of the Trinity on their own by just reading the Bible?

Question

How likely is it for a person, who has never heard of the concept of the Trinity before, to discover Trinitarianism, independently, on their own, by just reading the Bible? Are there any published testimonies from Christians who became Trinitarians in this way?

For the purposes of this question, I'm assuming the definition of the Trinity proposed by the Athanasian Creed:

Whosoever will be saved, before all things it is necessary that he hold the catholic faith. Which faith unless every one do keep whole and undefiled, without doubt he shall perish everlastingly. And the catholic faith is this: that we worship one God in Trinity, and Trinity in Unity; neither confounding the Persons, nor dividing the Essence. For there is one Person of the Father; another of the Son; and another of the Holy Ghost. But the Godhead of the Father, of the Son, and of the Holy Ghost, is all one; the Glory equal, the Majesty coeternal. Such as the Father is; such is the Son; and such is the Holy Ghost. The Father uncreated; the Son uncreated; and the Holy Ghost uncreated. The Father unlimited; the Son unlimited; and the Holy Ghost unlimited. The Father eternal; the Son eternal; and the Holy Ghost eternal. And yet they are not three eternals; but one eternal. As also there are not three uncreated; nor three infinites, but one uncreated; and one infinite. So likewise the Father is Almighty; the Son Almighty; and the Holy Ghost Almighty. And yet they are not three Almighties; but one Almighty. So the Father is God; the Son is God; and the Holy Ghost is God. And yet they are not three Gods; but one God. [...]

Note: Why am I asking this question? Because it would be interesting to know to what extent the doctrine of the Trinity can be inferred from Scripture alone, without any significant cultural bias influencing the individual's private interpretation of the text in favor of a particular doctrine. If unbiased readers consistently fail to become Trinitarians, that should be food for thought. On the contrary, if those testimonies actually exist, that should be food for thought as well. So, whatever the answer, I personally find this question quite interesting.

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Related: Are there published testimonies from Christians who had the truth of the Trinity revealed to them through the Holy Spirit?

Answer 1

The simple answer is: there are a lot, in the form of Trinitarian theology books published by professional theologians. One example is the 2021 book Contemplating God with the Great Tradition: Recovering Trinitarian Classical Theism by a professional theologian and Baptist minister Craig A. Carter reviewed here and discussed in an interview here. For an example of the continuing relevance of the Nicene formula for today to battle new understanding of God that is NOT Biblical, read his July 2021 Credo Magazine article Why We Must Reject Social Trinitarianism: It is neither Nicene nor Biblical.

• Surely a professional theologian who, by virtue of their training is well versed in exegesis and philosophical/historical/theological nuances of the critical terms used, is qualified to submit a "testimony" despite that the reasoning used comes from objective sources and methods?
• Surely if the objective source & method is enough we do not need special subjective revelation/prophecy/insight, which would then dilute the applicability of this Divine Truth to those do not possess similar subjective revelation?
• Surely we would not want to label the objective reasoning as "private interpretation" since many other theologians over hundreds of years being raised in multiple cultures and mother-tongues came out with the same conclusion?
• Surely we don't expect a non-professional theologian to come up with word-for-word definition of the Trinity as though it comes by dictation of the Holy Spirit, since the original 4th-5th century formulation itself came after many deliberation by church fathers who themselves were professional theologians?

Granting that the Bible alone may give support to non-Trinitarian positions, and that some pruning of theological options by the early church fathers is necessary to come up with the orthodox formulations of the Trinity, it is invalid to infer that these pruning is necessarily due to special insight / revelation to special church fathers (subjective) because then it could amount to the necessity of an oral tradition or of the necessity of prophecy beyond the canon. Instead, the standard mainstream narrative is that the Apostolic Tradition preserves the deposit of faith from the original apostles (1 Tim 6:20, 2 Tim 1:14, 1 Cor 11:2, Col 2:8) and this pruning / preference is simply due to a growing explicitness of a position held by the apostles from the very beginning. The ultimate test would be: if there is a time machine and that the apostles were present in the councils of Nicaea and Chalcedon, they would side with the orthodox theologians.

Thus, according to standard mainstream narrative, the creedal formulation of the Trinity is fully Biblical since the seeds are there. We can then logically and reasonably hold to sola scriptura's principle of the sufficiency of Scripture (see an argument for this in a 1997 Christian Research Journal article What Really Happened at Nicea? by evangelical Reformed apologist James R. White). Later prophecy / revelation a la LDS's Book of Mormon is not needed

CONCLUSION: What matters is that the formulation is consistent with the whole Bible.

• It does not have to be the only interpretation possible, but should NOT have to rely on unnatural / strained interpretation of certain Bible verses.
• It can use Greek philosophical concepts as long as they don't corrupt the original Hebraic conception of God implicit in the OT. After all, the Greek Septuagint used by the apostles necessarily used Greek words to translate the OT, which in some instances expanded the original meaning of the words outside the Bible. Similarly, just because the formulation of the Trinity is using terms not found in the Bible and the terms were put in service BEYOND the Latin/Greek non-Christian usage (see Substance and Person in Tertullian and Augustine) it doesn't make it unbiblical.
• Expecting non professional theologians to come up with word-for-word definition of the Trinity is as unrealistic as expecting an engineer to re-discover Newton's / Einstein's law of physics. What matters is that the Physics formulas are consistent with how things act in nature and that the Trinitarian formula is consistent with what God has revealed of His nature in Jesus and in the Bible (as a record of the sanctioned prophets and original apostles's deposit of faith).

Answer 2

It is extremely unlikely that this has happened.

That is not because it is impossible to deduce the Trinity from the Bible, but because anyone studying the Bible in sufficient depth to be able to deduce the doctrine of the Trinity would almost certainly know enough about Christianity in general to already know about the Trinity. In a similar way it is possible that a very clever physicist today could deduce Einstein's Theory of Relativity on their own. But anyone with sufficient knowledge of physics today would already have been taught Einstein's Relativity and so wouldn't need to deduce it on their own.

The doctrine of the Trinity was not established by a single person, but done though the work of very many theologians and much debate. It required very detailed knowledge of biblical languages, Jewish theology and much more. It rests in a large part on interpreting seemingly contradictory statements in different Bible books. It's also true that the original formulators did not subscribe to the modern limited view of "Sola scriptura", but accepted the role of the Spirit in leading Christians to the truth.

Probably the closest thing to the "independent discovery" question is to examine the doctrines of the independent churches that came out of the Reformation. Such churches strongly rejected the doctrine of the Roman Catholic church, and many subscribed to Sola Scriptura, basing their new doctrines only on scripture. However despite that, and despite rejecting many Catholic doctrines where they did not find scriptural support, hardly any of them chose to reject the Trinity. In short when the Reformation theologians were testing Catholic doctrine to see if it could be supported from the Bible, and rejecting many doctrines, virtually all considered the Trinity to have Biblical support.