In the later years of his life, popular British philosopher C.E.M. Joad said, “I now believe that the balance of reasoned considerations tells heavily in favour of the religious, even of the Christian view of the world.”(26). The truth is, the only valid worldview is the Christian worldview, and the only Christian worldview is the Biblical worldview. Therefore if we desire to know of the importance of logic to the Christian worldview we must first ask, “How important is logic to the Bible?” Without the Bible there is no Christian, nor is there a Christian World view. It is the desire of this author to display how important the tool of logic is to understanding the Bible, how the Bible uses logic, and how the Christian worldview relies on logic.
Logic is “the science of necessary inference” (Clark 1) or “the study of argument” (Engel 304). Logic (or reason) is not truth. Logic is the tool by which we appropriate truth. The Puritan Wilhelmus a’Brakel says,
Reason is the vehicle by which one comes to the conclusion that a particular doctrine is contained in a given text, and by necessary consequence may be deduced from the text. Reason judges whether the proper conclusion has been made, but not whether the doctrine which has been deduced from the text is true. (a’Brakel)
Logic, like reading, writing, and arithmetic, is a tool of discovery, and actually precedes all other tools of discovery because without thinking rightly, words, numbers, and images are meaningless. Even to read this post, one would need to understand the rules of English grammar. These rules are fundamentally based on logic.
Logic is undeniable, unavoidable, self-evident, or self-explanatory. Further, one cannot not use it, nor can one deny it, as one has to use logic to refute it. Therefore logic is either used correctly or incorrectly in all things.
Ronald Nash notes:
A denial of logic has consequences not only for epistemology and metaphysics, but for ethics as well. If all predications are true, there is no difference between walking to a nearby city and walking over a cliff; there is no difference between drinking milk and imbibing arsenic. But obviously there is a difference. (Nash 105)
Four Fundamental Laws of Logic
The first law of logic is the law of contradiction (sometimes called the law of non-contradiction). The law of contradiction symbolically expressed is “Not both A and not A.” That is, any given word or subject cannot be both itself and not itself at the same time. There is no black whiteness, no tall shortness, and no square circle. If 2 +2 = 4, then it cannot also equal 5, 12, or eggplant.
Likewise words must have definite meaning. In the sentence, “Moses was an hundred and twenty years old when he died”, the text is not saying Moses was a Swedish scientist, or that he owned a popcorn stand in New York, or that he never ate lima beans. Likewise in our example, the word Moses does not mean Samson, the word was does not mean wasn’t, and the word died does not mean flew. For words to mean something, they must also not mean something at the same time. The law of contradiction is essential in understanding all meaningful communication.
The law of excluded middle states “A or non-A,” that is, a proposition or statement must be either true or false, but cannot be both true and false. A perfect example of the Law of excluded middle is found in Matthew 12:30 where Jesus says, “He that is not with me is against me; and he that gathereth not with me scattereth abroad.” Here Christ is displaying the law of excluded middle by eliminating the possibility of the excluded middle. If you are not with Christ, you are by default (excluded middle) against him. The law of excluded middle leaves no room for equivocation, and is an essential part of logical argument.
The Law of Identity
The law of identity has already been discussed somewhat under the heading of Contradiction. The law of identity simply states that A=A. If John the Baptist says regarding Christ, “Behold the Lamb of God, which taketh away the sin of the world”, Christ cannot also be not be the Lamb of God which taketh not away the sins of the world. That is to say, things are what they are. The old cliché “a rose by any other name is still a rose” is also a prime example of the law of identity.
The Law of Logical Inference
The last primary law of logic is the law of logical inference. This law demonstrates the certainty of a truth by inferential deduction. The symbolic form of this law is, “If A=B and B=C, then A=C”, or “If A then C”. The Westminster Confession of Faith expresses this law very well when it says, “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 (Emphasis mine) (Confession 22). The finest example of logical inference in the Bible is the doctrine of the Trinity. The word Trinity is not found anywhere in the Word of God expressly, yet an end to end study of Scripture quickly points out that the Father, the Son, and the Holy Spirit, while being distinct Persons are all partakers in the attributes that are God. See, for example, Deuteronomy 6:4; Ephesians 1:3; John 1:1; 20:28; Acts 5:3-4; and Mark 12:29-30. Also see John 2:19-21; Romans 8:11; 1 Peter 3:18; 1 Thessalonians 1:10; and Acts 2:24, 32; 4:10 and 17:30-31. The logical inference of these verses is that God is three in Person but one in Substance, hence the Tri-Unity of God, or the Trinity.
The Laws of logic are fundamental to meaningful dialogue and discourse. Whether it is reading the stop sign on the corner of a street, or astrophysics, logic is essential to all human predication.
Logic, God, and the Bible
The first indication that the Bible is a logical book should be its form. The Bible is a series of recognizable characters (law of identity), which make up recognizable words (law of identity, and excluded middle), which make up understandable sentences (law of identity, excluded middle, and contradiction) that teach truth. The Bible came to us in the form of words, and unless words have meaning, they are useless.
Mark 12:30 says that we are to “…love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind, and with all thy strength” (emphasis mine). This is the first and greatest commandment according to Christ. We would do well to notice the command to love God with our entire mind. In fact the logical reasoning of the mind is an important aspect of Biblical love and worship God-ward. Can we worship the One who we know nothing of? Can we love the One who we never met? Isaiah 1:18 says, “Come now, and let us reason together”. The words reason, know, knowledge, understand, believe, and comprehend, are used over one thousand one-hundred and sixty-six times in the Word of God. We would do well to take notice of God’s demand on logic when He gave us His Word. God wants us to understand Him, and to do so we must not only think, but also think as He thinks. Our knowledge and God’s knowledge must intersect at some point for us to understand Him with knowledge, reason, and truth. His understandability comes to us in the Word of God via His transcendence, which is His permeation of all things — inc
luding the Human mind. How can God command us to reason “together” if our reasoning is different than His?
Do we know all that God knows? Never. However, what we do know about God is the same thing that God knows about Himself because God is logical. We might put it another way by saying that logic is a part of God’s communicable attributes in man. Robert Reymond in his New Systematic Theology of the Christian Faith says it well, “Christians should be overwhelmed by the magnitude of this simple truth that they take so much for granted- that the eternal God has designed to share with us some of the truths that are on his mind. He condescends to elevate us poor undeserving sinners by actually sharing with us a portion of what he knows (emphasis his) (Reymond 102).
For instance, Carl F.H. Henry remarks:
…Scripture affirms that God is the source and ground of reason and truth and that the imago Dei in which He created and preserves humanity includes rational and moral capacities. The laws of logic are not a speculative prejudice imposed at a given moment of history as a transient philosophical development. Neither do they involve a Western way of thinking, even if Aristotle may have stated them in an orderly way. The laws of valid inference are universal; they are elements of the imago Dei. In the Bible, reason has ontological significance. God is Himself truth and the source of truth. Biblical Christianity honors the Logos of God as the source of all meaning and considers the laws of thought an aspect of the imago.
R.C. Sproul, John Gerstner, and Arthur Lindsley similarly note regarding logic that without it: “… the Scriptures (and any other writings) would have no means to distinguish between truth and falsehood, righteousness and unrighteousness, obedience and disobedience, Christ and Antichrist.”
The Bible is logical.
Biblical Uses of Logic
We turn now to demonstrate some of the biblical uses of logic found in the pages of the Word of God.
Christ, Logic, Pharisees and the Sadducees.
The Bible is replete with examples of all kinds of logic. For the sake of time we will isolate ourselves to the twenty-second chapter of the book of Matthew to display 3 examples of Christ’s use of logic (Robbins).
In Matthew chapter 22 we find Christ using logic to silence his critics. In the race to discredit and dishonor Christ the Sadducees confront the Lord in an attempt to trip him up and bring him into disrepute.
They present to him a scenario of a woman who married a man who soon passed away. Having no children, the dead man’s brother marries his widow and likewise also dies. This scenario is repeated seven times with seven brothers and the Sadducees finally ask, “Therefore in the resurrection whose wife shall she be of the seven? for they all had her”.
Christ was very quick to see through the logical fallacy of the Pharisees argument. The Pharisees would have to answer their own question before they could proceed with their argument. Why was the widow allowed to remarry in the first place? Because the marriage contract terminates after death- the bond is severed. For the Pharisees to present this situation to the Lord they would have to presume the very thing they are trying to deny- that the marriage contract has ended. This is known as reductio ad impossible meaning “reduced to the impossible”, or the proses of deducing the conclusion to be false from the given premise, thus demonstrating the falsity of the premise. Christ answers very rightly, “For in the resurrection they neither marry, nor are given in marriage, but are as the angels of God in heaven” (verse 30).
Next we find these words, “But when the Pharisees had heard that he had put the Sadducees to silence, they were gathered together. Then one of them, which was a lawyer, asked him a question, tempting him, and saying, Master, which is the great commandment in the law?”
Again the Lord recognizes the fallacy of the question as non sequitur (it does not follow). The lawyer was trying to get Christ to commit a fallacy by placing one of the 10 commandments above the others in importance (an impossible task). The truth of the matter is certain questions are not always logical simply because they are asked by lawyers or because they are in intelligible language. “Have you stopped beating your wife?” is another prime example of this kind of illegitimate question, not to mention the classic, “Can God make a rock so heavy He can not pick it up”? These are nonsensical questions that have no answer.
Knowing the fallacy of the question Christ answers the best way possible, by summing up the law of God. “Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbour as thyself. On these two commandments hang all the law and the prophets” (vv. 37-39).
The last example we shall look at in chapter 22 of Matthew is found in verses 42-46 where Christ turns the tables on the attackers and goes on the offensive himself, “Saying, What think ye of Christ? whose son is he? They say unto him, The Son of David. He saith unto them, How then doth David in spirit call him Lord, saying, The LORD said unto my Lord, Sit thou on my right hand, till I make thine enemies thy footstool? If David then call him Lord, how is he his son?”
Here Christ uses the logical laws of contradiction and identity in the form of a syllogism. The symbolic form again would be “Since A=B and B=C, then A=C.” As a written syllogism it would appear like this:
Premise 1. The Christ is the son of David.
Premise 2. David calls his son LORD (Yahweh).
Conclusion. The Christ is a human son of David who is also Yahweh.
Christ’s argument is devastating by proving his humanity and his divinity in one powerful logical syllogism. His opponents were so roundly silences that the Scriptures tell us, “And no man was able to answer him a word, neither durst any man from that day forth ask him any more questions (verse 46).
Logic is essential to a Christian worldview because it is an indispensable part of the Bible itself. If we are to look at the world and judge it with any degree of accuracy, we must first know that the Word says, and then give arguments from the Word to the world. Logic is not a convention of man but is seeded in the attributes of God.
So in considering the primary question of how important logic is to the Christian worldview, the answer should be plain. If our worldview must be governed by God, and God has set his governance in the Word, “According as his divine power hath given unto us all things that pertain unto life and godliness, through the knowledge of him that hath called us to glory and virtue” (2 Peter 3:1), then the answer is simple, “Thy Word is truth” (John 17:17), and everything flows logically from it.
Joad, C.E.M. Recovery of Belief. London: Faber and Faber, 1955.
Nash, Ronald. The Word of God and the Mind of Man. Phillipsburg, NJ: Presbyterian and Reformed, 1982.
Henry Carl F.H. Towards a Recovery of Christian Belief Wheaton, IL: Crossway Books, 1990.
Sproul, R.C., John Gerstner, and Arthur Lindsley. Classical Apologetics. Grand Rapids: Zondervan Publishing House, 1990.
Westminster Divines. Westminster Confession of Faith. Glasgow: Free Presbyterian Publications, 1995.
a’ Brakel, Wilhelmus. The Christian’s Reasonable Service, Volumes I and II. CD-ROM. Escondido: Ephesians Four Group, 1999.
Reymond, Robert. L. A New Systematic Theology of the Christian Church. Nashville: Thomas Nelson Publishing, 1998.