For a more complete discussion of this subject, see Faith and Reason More Fully Defined.

“Mere Human Logic.” This phrase seems to be increasing in its use among evangelical speakers and writers. Unfortunately, if followed with consistency, Christianity becomes impossible either to understand or to be coherent. Review all that has been presented here. Then, consider. (1) Reason as logic is the very fabric of language communication, and there is no other form of communication! (2) Who structured human language—God Himself! “Mere human logic” is God’s design for human language and communication. To call it “mere” is to deprecate God. He does not create “mere”; He creates great and glorious.

At least one origin of this claim seems to be several systematic theology texts. These theologians seem to have the right intent to take a solid stand for the omniscience of God and the infinite extent to which His mind and understanding exceeds that of man. I have no quarrel to give God his highest glory in wisdom. However, He has created us in His own image. God chose language and its necessary structure for communication. He pushes His people to understand as much as they are able with His Special Revelation as the basis and limiting factor for knowledge and truth (Romans 12:2; Colossians 1:9, 2:2). “The secret things belong to the LORD our God, but those things which are revealed belong to us and to our children forever, that we may do all the words of this law” (Deuteronomy 29:29). By this statement, an incredible amount of knowledge is needed to be able to obey Him! By this statement, also, an entire system of ethics is named (“this law”).

There would be no hermeneutics, and thus no interpretation of Scripture, without logic! In R. C. Sproul’s book, Knowing Scripture, Chapter Four, he presents ten rules of hermeneutics—none of which are clearly stated from Scripture. On my worldview website, I have added 13 more rules, none of which are clearly stated in Scripture. In fact, what may be the most important hermeneutic, the analogy of Scripture—that Scripture must interpret itself where possible is not stated in Scripture. All these are logically derived from Scripture, as the Westminster fathers designed in Chapter 1, Section 6, of their Confession of Faith: “The whole counsel of God concerning all things necessary for his own glory, man’s salvation, faith and life, is either expressly set down in Scripture, or by good and necessary consequence may be deduced from Scripture.”

So, “mere human logic” should be changed to “the great logic of God is His image in man. Oh, by the way, there would be no one word, “Trinity,” for the three Persons of the Godhead without logic.

Four Senses (Uses) of “Logic”

The uses of the word, “logic.” “There “are four senses (definitions) in which the word logic is used: (1) at the theoretical and symbolic level is a comprehensive term that refers to sets of axiomatic relationships, ‘an analysis and evaluation of the ways of using evidence to derive correct (true) conclusions’ (Ed-empirical inference) (2) in common speech at a nontechnical level is a synonym for words such as ‘workable,’ ‘reasonable,’ and the like a logical plan may be a workable plan, an illogical step may be a rash step; (3) (in) a formal presentation of an argument: that is, people engage in ‘logical argument,’ whether or not there are fallacies in the steps (that) they take; and (4) in common speech may refer to a set of propositions or even an outlook which may or may not be ‘logical’ in the first sense….for example … the logic of the marketplace or the logic of ecology.” (D. A. Carson, Exegetical Fallacies, Baker Academic Books, 2nd edition, pp. 87-88,)

Ed’s Comments

The reader should note that #1 represents logic in its formal sense as inductive inference. Evidence is gathered, coherence is recognized, and conclusions drawn about the probability of universals.

A better name for #3 might be “rational” thinking, as it does not involve the formal steps of logic, but an attempt at clearly drawing one conclusion from other facts and statements. What is reasonable or rational may or may not be formally “logical.”

#2 and #4 may include almost any kind of reasoning in serious or casual conversations. It is doubtful that “logic” should be used for this process at all, as it hides the important use of formal logic. “Reasonable” might be a better word here.

It is most important that readers understand that there is a discipline of deductive logic because it stands in stark contrast to all the other definitions. Formal logic can start with true statements (premises, axioms, presuppositions, etc.), and if the process of logic is applied correctly, then the conclusions are also true.

For example, The Trinity is common to all those who profess true Christianity, yet “trinity” does not appear in the Bible. The logical steps are these:

Only God is omniscient, omnipresent, and omnipotent.

The Father, Son, and Holy Spirit all have these attributes.

Therefore, the Father, Son, and Holy Spirit are One God and Three Persons.

“Trinity” is an arbitrary choice of a word to apply to this conclusion. The word itself does not make its own concept true. The concept of Trinity is a logical conclusion from the premises which are absolutes. So, the conclusion argued logically is as true as its premises. All the steps, as a whole, is called a syllogism.

The reader may need to wrestle with this process. It cannot be done apart from reviewing at least the first few chapters of a book on formal logic. A failure to understand the use of formal logic will greatly hamper one’s attempts at a Biblical worldview.

The phrase “mere human logic” shows ignorance of the process of formal logic and its power to reason to truth from true propositions. For example, what about “mere human mathematics,” as being unreliable and untrustworthy?

*The same comments above apply the word, “reason.” I wrote the article on “logic,” but everything said above applies to “reason.” Gordon Clark equates logic and reason. He also discusses three uses of “reason”:

In theology (and I would add, philosophy), reason has borne several meanings. It can mean non-revelational knowledge; it can mean knowledge derived by logic alone; and it can mean and has often meant knowledge based upon sensory experience. The latter, though it is of frequent usage, seems to veer a little too far from the etymological meaning of ratio. (Logic, page 26)

For more on the use of logic in the interpretation of Scripture, see Logic by John Frame. Even better, see The Westminster Confession of Faith and Logic.

God and Logic: In the beginning was the … logic

For the process of formal logic, see