The Biblical Imperative of Logic - Part 2

By Phillip G. Kayser · 2015-9-24

Continued from part 1

In my last post I sought to demonstrate that the historic church saw logic as eternally existing in God’s mind, as being revealed by God to man (via both general revelation and special revelation), and as being a subset of theology (or the study of God). In this post I will seek to show that logic itself is revealed in Scripture and that Scripture cannot be understood apart from logic.

The logic in God’s mind was perfectly revealed in the Bible and (though marred by sin) is also revealed in man’s nature as part of God’s image. Postmodernist rejection of logic is simply one manifestation of unbelief’s suppression of the truth in unrighteousness (Rom. 1:18).

It must be categorically asserted that logic is embedded in the Scripture and cannot be avoided without avoiding the Scriptures themselves.[1] Scripture also assumes a prior logical understanding on the part of the readers.[2] In other words, it assumes that logic is part of man’s innate reasoning powers. John Frame has shown how it is impossible to do theology, to apply Scripture to our lives, to understand the reasoning of Scripture, to communicate or even to have assurance of salvation apart from logic.[3]

In several of his books, Gordon Clark has shown that this innate power to logically reason and discourse is the “image of God” in man.[4] It is not something alien that we impose on Scripture. Christ the Logos[5] (John 1; 1 John 1:1) is the common Author of both since He not only gave Scripture, but also “gives light to every man who comes into the world” (John 1:9). It is this innate grasp of logic that enables man (with effort) to perceive Scriptural argument just as the rules of language are innate and enable us (with effort) to perceive the grammatical forms of the text.[6] It is true that the noetic effects of sin make us very prone to error in our use of logic. But this just makes our study of logic that much more important if we are to grow in our understanding of ethics.

Of course, it is not enough to be a logical thinker. The first quote I gave from Augustine (in my last post) demonstrated from Paul’s use of logic that we must also start with the right axioms if we are to be pleasing to God. These axioms or presuppositions[7] must come from the infallible source of Scripture if we are to avoid the notorious problems that plague non-biblical systems of thought.

In this post I will not be able to demonstrate all of the ways in which the Bible presupposes logic and uses logic – it is, after all, present on every page of the Bible. But one brief example should suffice. In Matthew 12:24-30 Jesus used the following forms of logical thinking:

  • Argument from analogy (vv. 25-26)

  • The law of inference (v. 26)

  • An argument that amounts to reductio ad absurdum (vv. 25-26)

  • A second argument from analogy (v. 27)

  • Another use of the law of inference (vv. 28,29)

  • Yet another argument from analogy (v. 29)

  • The law of contradiction (v. 30)

  • The law of excluded middle (v. 30)[8]

Christ’s use of these logical arguments would be meaningless if logic was simply a Greek construction and not a universal way of evaluating truth statements. Christ and the rest of the prophets stand strongly against the postmodernists who reject the authority of logic.

Postmodernism insists on three things that are contradicted by the Bible. First, they deny that one can know anything with certainty, whereas Scripture affirms that we can know many things with certainty (Luke 1:4; Prov. 22:21; Josh 23:13; Acts 1:3; etc.; see the 70 times that the phrase “that you may know” occurs).

Second, postmodernists deny that truth is objective or that logic is universal and affirm instead that truth is subjective (true for me, but not necessarily for you). In contrast, Scripture affirms that the entirety of Scripture is truth by which all other truth claims can be judged (Ps. 119:160; John 1717). It is objective, and though men may “suppress the truth in unrighteousness” (Rom. 1:18), it still remains truth.

Third, postmodernism believes that truth is relative. In other words, it is not true for all time, all places, and all people. In contrast, Scripture preaches the same message “everywhere” ((Luke 9:6; Acts 8:4; etc.), affirms that “every one of Your righteous judgments endures forever” (Ps. 119:160), and states that even those who deny the truth will be condemned by that truth since it still applies to them (2 Thes. 2:12 ).

The church must cast off the thinking of postmodernism, and in submission to the axioms of Scripture, must once again embrace the logic of God. Study logic!


  1. Just as J.C. Keister, “Math and the Bible,” in The Trinity Review (No. 27/Sept/Oct, 1992) has shown the axioms of mathematics to be embedded in the Scripture, there are others who are developing the rules of logic from Scripture to show the Biblical warrant for such a complete system of logic. Some might ask, “Which system of logic?” Actually there are not truly different systems of logic. Gordon Clark has shown that there is a problem with Bertrand Russell’s modification of Aristotelian logic, and cautions against it, However, the basic structure of logical thinking cannot be different. For proof of where Russell went wrong, see Logic, pp. 83ff.

  2. Let me quote at length from John Frame, The Doctrine of The Knowledge of God (Phillipsburg, NJ: Presbyterian & Reformed Publishing Company, 1987), pp. 251-254.

    One may not, however, do theology or anything else in human life without taking account of those truths that form the basis of the science of logic. We cannot do theology if we are going to feel free to contradict ourselves or to reject the implications of what we say. Anything that we say must observe the law of noncontradiction in the sense that it must say what it says and not the opposite...

    When we see what logic is, we can see that it is involved in many biblical teachings and injunctions. (i) It is involved in any communication of the Word of God. To communicate the Word is to communicate the Word as opposed to what contradicts it (1 Tim. 1:3ff; 2 Tim. 4:2f.). Thus the biblical concepts of wisdom, teaching, preaching, and discernment presuppose the law of non-contradiction.

    (ii) It is involved in any proper response to the Word. To the extent that we don’t know the implications of Scripture, we do not understand the meaning of Scripture. To the extent that we disobey the applications of Scripture, we disobey Scripture itself. God told Adam not to eat the forbidden fruit. Imagine Adam replying, “Lord, you told me not to eat it, but you didn’t tell me not to chew and swallow!” God would certainly have replied that Adam had the logical skill to deduce “You shall not chew and swallow” from “You shall not eat.” In such a way, the biblical concepts of understanding, obeying, and loving presuppose the necessity of logic.

    (iii) Logic is involved in the important matter of assurance of salvation. Scripture teaches that we may know that we have eternal life (1 John 5:13). The Spirit’s witness (Rom 8:16ff.) plays a major role in this assurance; but that witness does not come as a new revelation, supplementing the canon, as it were. So where does the information that I am a child of God come from - information to which the Spirit bears witness? It comes from the only possible authoritative source, the canonical Scriptures. But how can that be, since my name is not found in the biblical text? It comes by application of Scripture, a process that involves logic. God says that whosoever believes in Christ shall be saved (John 3:16). I believe in Christ. Therefore I am saved. Saved by a syllogism? Well, in a sense, yes. If that syllogism were not sound, we would be without hope. (Of course, the syllogism is only God’s means of telling us the good news!) Without logic, then, there is no assurance of salvation.

    (iv) Scripture warrants many specific types of logical argument. The Pauline Epistles, for instance, are full of “therefores.” Therefore indicates a logical conclusion. In Romans 12:1 Paul beseeches us, “Therefore, by the mercies of God.” The mercies of God are the saving mercies that Paul has described in Romans 1-11. Those mercies furnish us with grounds, reasons, premises for the kind of behavior described in chapters 12-16. Notice that Paul is not merely telling us in Romans 12 to behave in a certain way. He is telling us to behave in that way for particular reasons. If we claim to obey but reject those particular reasons for obeying, we are to that extent being disobedient. Therefore Paul is requiring our acceptance not only of a pattern of behavior but also of a particular logical argument. The same thing happens whenever a biblical writer presents grounds for what he says. Not only his conclusion but also his logic is normative for us. If, then, we reject the use of logical reasoning in theology, we are disobeying Scripture itself....

    (v) Scripture teaches that God himself is logical. In the first place, His Word is truth (John 17:17), and truth means nothing if it is not opposed to falsehood. Therefore His Word is noncontradictory. Furthermore, God does not break His promises (2 Cor. 1:20); He does not deny himself (2 Tim. 2:13); He does not lie (Heb. 6:18; Tit. 1:2). At the very least, those expressions mean that God does not do, say, or believe the contradictory of what He says to us. The same conclusion follows from the biblical teaching concerning the holiness of God. Holiness means that there is nothing in God that contradicts His perfection (including His truth). Does God, then, observe the law of noncontradiction? Not in the sense that this law is somehow higher than God himself. Rather, God is himself noncontradictory and is therefore himself the criterion of logical consistency and implication. Logic is an attribute of God, as are justice, mercy, wisdom, knowledge. As such, God is a model for us. We, as His image, are to imitate His truth, His promise keeping. Thus we too are to be noncontradictory.

    Therefore the Westminster Confession of Faith is correct when it says (l, vi) that the whole counsel of God is found not only in what Scripture explicitly teaches but also among those things that “by good and necessary consequence may be deduced from Scripture.” This statement has been attacked even by professing disciples of Calvin, but it is quite unavoidable. If we deny the implications of Scripture, we are denying Scripture....

    I would therefore recommend that theological students study logic, just as they study other tools of exegesis. There is great need of logical thinking among ministers and theologians today. Invalid and unsound arguments abound in sermons and theological literature. It often seems to me that standards of logical cogency are much lower today in theology than in any other discipline. And logic is not a difficult subject. Anyone with a high school diploma and some elementary knowledge of mathematics can buy or borrow a text like I.M. Copi, Introduction to Logic and go through it on his own....

  3. See discussion in previous footnote.

  4. See for example Gordon Clark’s discussion in A Christian Philosophy of Education (Jefferson, MD: The Trinity Foundation, 1988), pp. 129-140

  5. Which has in its meaning both logic and discourse. Christ is the Word of God. He is also the Logic of God.

  6. This of course does not mean that we do not need to study language. But linguistic analysis has demonstrated that children from every language group use the same “rules” to make sense out of the patterns of words that they hear. There is something innate (God-given) that enables them to learn a language. See Gordan Clark, Religion, Reason and Revelation. In the same way, God’s people must study logic to improve their understanding of Scripture, but

  7. The New Testament word for "presuppositions" is στοιχείων. This word was used in classical Greek and by the Church fathers to mean the elementary or fundamental principles. In Geometry it was used for axioms, and in philosophy for elements of proof or the prwtoi sullogismoiv of general reasoning (Liddel and Scott, A Greek-English Lexicon, s.v.). Obviously both of these definitions are synonyms with "presuppositions."

    The New Testament teaches that the stoiceia are the "foundation" upon which our faith and practice rests (Heb. 5:12-6:3). We find our stoiceia in the Word of God (Heb. 5:12) and most specifically in the person of Jesus Christ (Col. 2:8-10; Heb. 6:1) revealed in them. The stoiceia of the world are the foundation of the non-Christian "philosophy" (Col. 2:8) and are diametrically opposed to the stoiceia of Christ the God-Man (Col 2:8-10). Our thoughts and actions are a logical outworking of these stoiceia in everyday life (Col. 2:20ff).

    We must recognize that the superstructure of our world-and-life view is antithetical to the superstructure of the heathen's world-and-life view, not because the superstructures do not have any things in common, but because of the way in which these superstructures are completely committed to their foundation or presuppositions. Paul gives us an example of this concept when he vigorously opposed the Galatian's succumbing to pressure to be circumcised and observe "days and months and times and years" (Gal. 4:10). Though the physical act of circumcision was not wrong (cf. 1 Cor. 7:19; Acts 16:3), the idea that lay behind it was destructive and led to syncretism, a denial of their presuppositions and an unintentional reversion to weak and pathetic presuppositions (Gal. 4:9).

  8. There are many postmodern thinkers who deny the law of excluded middle. For example, in mathematical philosophy the “constructionists” insist that a proposition is neither true nor false until we can construct an actual, finite proof. This is a blatant denial of the excluded middle. Intuitionistic logic denies the law of the excluded middle.

    William A. Dyrness, in Learning about Theology from the Third World (Grand Rapids: Zondervan, 1990), tries to apply this relativistic thinking to theology. He claims that since Hindus and other Easterners deny dualistic thinking, Christianity must not impose it upon them. Of course, he is advocating total relativism and postmodern thinking. But we must reject such relativistic thinking based on the authority of the Bible. The Bible uses the law of excluded middle over and over again.


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