Review of "Logic" by Clark.
A Book Review of Gordon H. Clark's Logic (The Trinity Foundation, 1998) 140 pages.
By Dr. W. Gary Crampton
Copyright 2001 © First Presbyterian Church of Rowlett

In the “Introduction” to this book, John Robbins asks the most pertinent question, “Why Study Logic?” Logic, which is defined as “the science of necessary inference,” is often belittled as unnecessary. After all, we are told, “life is deeper than logic; life is green, but logic is gray and lifeless.” Why then should we spend our time studying logic? Could we not better involve ourselves in something “more spiritual?”

In his Logic,[1] Gordon Clark, who taught the subject for years at the college and seminary level, instructs his readers about “the science of necessary inference.” Logic is a text book, and it is classic. In it Dr. Clark defines and deals with Informal Fallacies, Syllogisms, Sorites and other forms of Argument, Truth Tables, etc. All of the chapters are, in typical Clarkian fashion, systematic, and extremely well presented. But the most important thing the author does in the book under review is answer the question “Why Study Logic?”

In the “Postscript,” and elsewhere,[2] Dr. Clark presents a biblical view of logic. First, the Bible teaches that the Triune God is a God of knowledge, who is also the source and determiner of all truth. That which is true is true because God thinks it so. And since that which is not rational cannot be true (1 Timothy 6:20), it follows that God is rational, and the laws of logic are the way he thinks.

This is, of course, what the Bible teaches. God is not the author of confusion (1 Corinthians 14:33); he is a rational being, the Lord God of truth (Psalm 31:5). So much does the Bible speak of God as a God of logic, that in John 1:1 Jesus Christ is called the “Logic” of God: “In the beginning was the Logos, and the Logos was with God, and the Logos was God” (the English word “logic” is derived from the Greek logos used in this verse). John 1:1 emphasizes the rationality of God the Son. Logic is as eternal as God himself because “the Logos is God.” Hence, God and logic cannot be separated; logic is the characteristic of God’s thinking. So God and logic are one and the same first principle.

This should give us a greater understanding of the relationship of logic and Scripture. Since Logic is God, and since Scripture is a part of “the mind of Christ” (1 Corinthians 2:16), it follows that Scripture must be logical. What is said in Scripture is God’s infallible and inerrant thought. It expresses the mind of God because God and his Word are one. This being the case, the Bible is a logically consistent book.

Further, logic is embedded in Scripture. The very first verse of the Bible, “in the beginning God created the heavens and the earth,” necessitates the validity of the most fundamental law of logic: the law of contradiction (A is not non-A). Genesis 1:1 teaches that God is the Creator of all things. Too, it says that he created “in the beginning.” It does not teach, therefore, that God is not the Creator of all things, nor does it maintain that God created all things 100 years after the beginning. The verse assumes that the words God, beginning, created, and so forth, all have definite meanings. It also assumes that they do not mean certain things. For speech to be intelligible, words must have univocal meanings. What makes the words meaningful, and revelation and communication possible, is that each word conforms to the law of contradiction.

This most fundamental law of logic cannot be proved. For any attempt to prove the law of contradiction would presuppose the truth of the law and therefore beg the question. Simply put, it is not possible to reason without using the law of contradiction. In this sense, the laws of logic are axiomatic. But they are only axiomatic because they are fixed or embedded in the Word of God.

Also fixed in Scripture are the two other principle laws of logic: the law of identity (A is A), and the law of the excluded middle (A is either B or non-B). The former is taught in Exodus 3:14, in the name of God itself: “I AM WHO I AM.” And the latter is found, for example, in the words of Christ: “He who is not with me is against me” (Luke 11:23).

Logic, then, is embedded in Scripture. This is why Scripture, rather than the laws of logic, is selected as the axiomatic starting point of Christian epistemology. Similarly, God is not made the axiom, because all of our knowledge of God comes from Scripture. “God,” as an axiom, without Scripture, is merely a name. Scripture as the axiom defines God.

As we are taught in the Bible, man is the image of God (Genesis 1:26,27). God “formed man of the dust of the earth and breathed into his nostrils the breath of life; and man became a living soul” (Genesis 2:7). Adam became a type of soul that is superior to that of non-rational animals (2 Peter 2:12). Man, as God’s image bearer, is a rational being (Colossians 3:10). This is why the apostle Paul could spend time “reasoning” with his auditors “from the Scriptures” (Acts 17:2).

Moreover, because Christ is the Logos who “gives [epistemological] light to every man who comes into the world” (John 1:9), we are to understand that there is a point at which man’s logic meets God’s logic. In fact, John 1:9 denies that logic is arbitrary; it also denies polylogism, i.e., that there may be many kinds of logic. According to John, there is only one kind of logic: God’s logic. And the Logos gives to every image bearer of God the ability to think logically.

Man, then, has the capacity to think logically and to communicate with God. God created Adam with a mind structured in a manner similar to his own. In the Scripture, God has given man an intelligible message, “words of truth and reason” (Acts 26:25). God has also given man language that enables him to rationally converse with his Creator (Exodus 4:11). Such thought and conversation would not be possible without the laws of logic. Logic is indispensable to all (God-given) human thought and speech. This being so, we must insist that there is no “mere human logic” as contrasted with a divine logic. Such fallacious thinking does disservice to the Logos of God himself.

One might argue here that the fall of man rendered logic defective. But this is not the case. The noetic effects of sin indeed hinder man’s ability to reason correctly (Romans 1:21), but this in no way implies that the laws of logic themselves are impinged. In other words, it is not the laws of logic that are affected by the Fall, it is man’s ability to think logically that is so affected. As we have seen, the laws of logic are eternally fixed in the mind of God. They cannot be affected; they are eternally valid. Logic is fixed and universal; it is necessary and irreplaceable.

Conclusion: Why should we study logic? First, because we are commanded by Scripture to do so. Second, as taught by the Westminster Confession of Faith (I:6), all things necessary for our faith and life are either expressly set down in Scripture, or can be logically deduced from Scripture. Logic then is indispensable to the study of the Word of God. And third, logic is not only indispensable to the study of theology, it is necessary for our study of all subjects. In the words of Augustine: “The science of reasoning is of very great service in searching into and unraveling all sorts of questions that come up in Scripture….The validity of logical sequences is not a thing devised by men, but it is observed and noted by them that they may be able to learn and teach it; for it exists eternally in the reason of things, and has its origin with God.”

[1] Gordon H. Clark, Logic (The Trinity Foundation, 1985, 1998).

[2] Gordon H. Clark, “God and Logic,” The Trinity Review (November/December 1980).