Logical Fallacies Employed in Trinitarian Theology


“Logic,” from the Greek word logos, is the science of correct reasoning, and provides tools for analyzing the form and content of arguments. Logic addresses the relationship of premises (or evidence) to conclusions, and helps us determine whether our reasoning is straight or crooked. That is, does our conclusion necessarily follow from the premises, or have we “jumped” to conclusions. The disciplines of logical reasoning are fast becoming a thing of the past, an artifact of a classical education. Feelings, emotions and rhetoric (persuasive speech) are most often the basis of what passes for “reasoning” today. But, if we are ever to “correctly handle the word of truth” (2 Tim. 2:15), we are going to have to learn to think correctly.

One of the best ways to understand and apply the basics of logic is by becoming familiar with logical fallacies, that is, examples of faulty reasoning. What follows are the main types of fallacious reasoning that we have encountered in the course of researching our book, One God & One Lord. Though the systems of classifying fallacies vary from author to author, we find that there is general agreement among teachers of logic that fallacies come in two general forms: formal and informal. The “formal” fallacies revolve around the syllogism form, which involves a major premise, a minor premise and a conclusion. “Formally” fallacious logic involves some transgression of the proper form of syllogistic reasoning. “Informal” fallacies are those employed in everyday speech, and for the most part involve different ways of slanting or avoiding evidence en route to a conclusion.


The fallacy of accent is employed whenever an emphasis is placed on a written or spoken communication in a way that materially alters its original or intended meaning. To interpret any piece of literature logically, one must be sensitive to the context and original meaning intended by the author and not alter that meaning by misplaced emphasis. This misplaced emphasis can occur quite subtly. Without changing a word, a piece of written material can be made to say something entirely different from what was intended by the author. A common form of this fallacy is the altering of punctuation, which is particularly significant for biblical research because the original text of Scripture contained no punctuation marks. For instance, the addition of a comma can dramatically alter the simple sentence, “God made man,” (as in God created man) to “God, made man” (as in God became man). What a big difference!

Likewise, “Woman without her man would be lost” is a seemingly straightforward sentence, but watch how the meaning can be dramatically changed by the addition of a period and a comma: “Woman. Without her, man would be lost.”

Luke 23:43 (NASB) says, “And he said to him, ‘Truly I say to you, today you shall be with me in Paradise,’” indicating that Jesus will be with the malefactor in Paradise later that same day. But if the comma is moved to the other side of “today,” an entirely different emphasis results: “Truly I say to you today, you shall (in the future) be with me in Paradise.” This is, in fact the correct rendering. [For further study read What was Jesus really saying to the malefactor in Luke 23:43?]

“Proof texting” is a common way that the fallacy of accent is employed. By isolating verses that appear to support a particular theological or doctrinal position, but by weighting them too heavily, contradictions are created with other verses on the same subject. For instance, with the exception of a few “proof texts,” the idea that “Jesus is God” is not consistent with the New Testament when considered as a whole. Not a Christian theologian, but a professor of logic, made the following astute statement regarding what is required for the logical interpretation of the Bible:

Selecting texts to give a one-sided presentation of the truth is a widespread method of propagating erroneous views. Out of the Bible can be drawn phrases or verses that justify everything under the sun, including contradictories. Read in context, the Bible may be a liberal document, but it is not that liberal. What we need to know is if the Bible as a whole [emphasis ours] supports a given position. [1]

It is a well-established hermeneutical principle among biblical interpreters that the difficult verse or passage must be interpreted in light of the clear and simple parallel verses or passages. The difficult or unusual must not be elevated and established as an altogether higher and better view than the rest of Scripture, as has been done with the Gospel of John, for example. Because it apparently presents a Jesus most compatible with Trinitarian orthodoxy, the Gospel of John is the one that is translated and distributed to potential converts more than any other. But has this been done honestly and logically, or by employing the fallacy of accent?


This fallacy is employed when terms crucial to an argument are not used in the same sense throughout the argument. It could also be called “changing the rules in the middle of the game.”

Equivocation can be clearly seen in the following argument:

Major premise: Every square is four-sided.
Minor premise: Your jaw is square.
Conclusion: Your jaw is four-sided. [2]

The reason the conclusion is invalid is that in the argument, the word “square” is used in two different ways. In geometry, a square is a four-sided polygon with equal sides and four 90° angles. In popular usage, a “square” jaw means something closer to “angular.” In the reasoning process, it is crucial that words be used precisely in the same sense when reasoning from one premise to another to a conclusion.

One person cannot be “God” and “the Son of God” without equivocating the term “God.” Trinitarians use the term “God” in the sense of “the Father” as distinct from “the Son” and “the Holy Spirit.” But, in calling Christ “God,” they use the term “God” in the sense of “the second person of the Trinity.” Thus, although the word “God” is the same, it is given two different meanings.

Often, Trinitarians equivocate the term “God” to mean a “triune God” composed of three persons. The editors of the NIV Study Bible equivocate the term “God” in this fashion when they handle 1 Corinthians 15:24-28. The passage clearly separates “God” from “Christ,” and asserts that Christ will submit to God for eternity “so that God may be all in all.” But, because of their doctrinal position that the Father and the Son are equal, neither can be “over” the other. Therefore, they minimize the Son’s submission to a matter of “administrative function,” and say that “The triune God will be shown to be supreme and sovereign in all things.”

To see the equivocation in the Chalcedonian formula of one person and two natures, look at the following argument:

Major premise: Jesus Christ is God (divine, deity, etc.).
Minor premise: God cannot be tempted (James 1:13).
Conclusion: Jesus Christ was tempted in all points (Hebrews 4:15).

It should be clear that there is something wrong with the argument, because the conclusion does not follow from the premises. The logical conclusion that should be drawn from the premises is that Jesus Christ cannot be tempted. Let us restate the argument in proper syllogistic form.

Major premise: Jesus Christ is God.
Minor premise: God cannot be tempted (James 1:13).
Conclusion: Jesus Christ cannot be tempted.

But now the logical conclusion of these premises creates a dilemma, because it contradicts Hebrews 4:15, which says that Jesus Christ was tempted in all points. One possible solution is that the term “tempted” is being used in an equivocal sense. We must therefore look at the definition of the word “tempted” and see if it is being distributed throughout the argument in the same sense. We find that the word “tempt” in the minor premise and the conclusion is the same concept, based on the Greek word, peirazo (to pierce or cut). The only other possibility is that the term “God” is being equivocated, as follows:

Major premise: Jesus Christ is God [the Son who became a human being while retaining his divine nature].
Minor premise: God (the Father) cannot be tempted (James 1:13).
Conclusion: Jesus Christ was not tempted in his divine nature, but he was tempted in his human nature because he became a man.

In the major premise, “God” is used in the sense of divine, deity, sharing the attributes of God, etc. In the minor premise, “God” refers to the Creator and the Father of Jesus Christ. This is a clear example of equivocating the term “God.” This standard orthodox argument also equivocates the term “man.” Jesus Christ is not an authentic man in this argument, because a “man” by definition does not have a “divine” nature.

To clarify orthodoxy’s equivocation of “man,” consider the following argument:

Major premise: Jesus Christ is a man (1 Tim. 2:5; Acts 2:22).
Minor premise: God is not a man (Num. 23:19).
Conclusion: Jesus Christ is God.

The word “man” does not have the same meaning in the above premises. In the first case, “man” is descriptive only of the part of his being that was human, because Trinitarians argue that Jesus was both a man and God at the same time: a God-man. So, anything that is asserted about him being a “man” is qualified by saying that he was also God. In equivocating the terms “man” and “God,” Trinitarians create a separate category of being for Jesus Christ and remove him from the normal and customary meaning of both terms as understood biblically and experientially. What is asserted about Jesus Christ could not be asserted about Adam, who was truly the archetypal “man.” Unless Jesus’ nature is completely comparable to Adam’s, he cannot properly and without equivocation be categorized as “man.” “100 percent God and 100 percent man” is 200 percent logical equivocation.

Law of Non-Contradiction

This law is completely fundamental to logical and rational thinking, as every student of philosophy knows. It states that “A” and “not A” cannot both be true at the same time and in the same relation. For instance, biologically speaking, Mark can be a father to his son and a son to his father, but he cannot be both a son and a father to the same person at the same time. So, regarding his relationship to his son, he cannot be both his son’s (biological) father and not his son’s father at the same time. He must be one or the other.

This law of non-contradiction is often jettisoned in theological discussions involving the Trinity or the natures of God and Christ. For instance, Jesus cannot be both a man and not-man at the same time and in the same relationship to what defines a man. If we define “man” in a way that makes “man” distinguishable from “God,” as a member of the species homo-sapiens with various physical and mental limitations, Jesus Christ cannot be a man and not-man at the same time. If he is “man” and “God” at the same time, and if we preserve the integrity of the definitions of these terms, Jesus is a logical contradiction. The only way out of this dilemma is to propose a third category of being called “God-man,” which of necessity renders him incapable of being included in either the category of “man” or “God.” Though some may find this theologically and mystically compelling, it is logically contradictory if the integrity of biblical language is upheld (as in, “God is not a man”—Num. 23:19).

Logical Identity

Logical “identity” is established by the following principle: whatever is true of A must also be true of B, and whatever is true of B must also be true of A. One point of dissimilarity disproves identity. The stakes get higher when this principle is violated in connection with the identity of God. Scripture identifies the term “God” with the term “Father.” God is the Father of our Lord Jesus Christ. That means that whatever is true of God must also be true of the Father of our Lord Jesus Christ. And whatever is true of the Father of Jesus Christ must be true of God also. Logically speaking, “God” cannot be both the Father of Jesus and Jesus himself, if language is to retain any meaning.

Straw Man

Attacking a straw man occurs when an opponent’s position is misrepresented in order to make it more easily refuted. This is very hard to avoid, and points up the need for dialogue with those with whom we disagree. Even if we cannot agree, we can at least represent each other’s position fairly and rebut it honestly. We have endeavored to do this throughout our book, One God & One Lord, and we invite those who disagree with us to let us know if we have misrepresented “orthodox” teaching.

Often, when Trinitarians hear our argument that Jesus is not God, they immediately respond by assuming that we are saying that Jesus is a “mere man.” This is a straw man argument because it is easy to refute the claim that Jesus was merely a man like the rest of us. On the contrary, the Gospels are full of evidence of his uniqueness as the monogenes (“one of a kind,” traditionally translated “only-begotten”). It is not demeaning to be made a man in the same way that Adam was made a man in the original Creation. He was the crowning achievement of that Creation. The issue is whether Jesus is to be compared to a fallen man, with the implication that he is then a partaker of man’s sinful nature. He had a fully human nature because God originally made man in His image. Man was made to reflect God’s life and goodness, and share in His attributes. So for Jesus to be “the image of God” is to say that he is completing the destiny originally designed for Adam in the original Creation, which Adam forfeited. There is nothing “mere” about that!

Undistributed Middle

This is a “formal” fallacy that relates to the proper form of syllogistic reasoning, which we must examine before discussing the undistributed middle. An argument can be logical in its form and yet lead to a false conclusion if one or both of the premises are false. The classic Roman Catholic argument for their veneration of the Virgin Mary is a good example:

Major premise: Mary is the mother of Jesus.
Minor premise: Jesus is God.
Conclusion: Therefore, Mary is the mother of God.

Protestants accept the premises but deny the conclusion. Such reasoning is illogical. We also deny the conclusion, but we do so because the argument is based on a false premise, not because the argument itself is invalid. At least Roman Catholics are consistent and logical in asserting their conclusion.

Seeing the proper form of syllogistic logic in symbols will help us understand the fallacy of the undistributed middle.

The undistributed middle is an illogical argument because the conclusion does not necessarily follow from the premises. It is like arguing: everything worthwhile is difficult to achieve; digging a giant hole from Maine to China is difficult to achieve; therefore digging such a hole is worthwhile. This is essentially the same reasoning as is sometimes employed by Trinitarians who argue in this fashion:

Major premise: God is the Savior.
Minor premise: Jesus is the Savior.
Conclusion: Jesus Christ is God.

The reason this argument is fallacious is that just because Jesus and God share a common title, name or attribute (Savior, Lord, etc.) does not make them identical. For example, consider this argument based upon the same major premise:

Major premise: God was the Savior of Israel.
Minor premise: Men who delivered Israel from enemies were saviors.
Conclusion: Men who delivered Israel from enemies were God.


Jesus Christ said that the Word of God is truth. God specifically says in Scripture that He wants men to come to a knowledge of this truth. If Christians are going to do so, then there must be an appreciation of what is logical and what is not. Otherwise, nonsense masquerading as spiritual truth will go undetected and the quality of people’s lives will suffer as a result of believing it.


1. A.J. Moulds, Thinking Straighter (University of Michigan Press, Ann Arbor, 1975), p. 46. Back to top

2. Robert J. Kreyche, Logic for Undergraduates (Holt, Rinehart, Winston, N.Y., 1961), p. 192. Back to top