Logic is a tool given by God to help us order our reasoning and obey Him. Through our reasoning faculties God communicates to us. For example, the Scripture teaches that God has all power, and through deductive logic I can conclude that God has the power to save me. We see the sun rise and the rain fall, and through inductive reasoning we conclude that God is good. Through the process of reasoning we understand His revelation to us better.

We read that there is one God, and that the Father is God, the Son is God, and the Spirit is God; Through good and necessary consequence we conclude that there is one God, and He exists in three Persons: Father, Son, and Holy Spirit. We see that logic makes the implicit explicit, it reveals the truth already there. Logic properly used adds nothing to scripture, but it helps set forth clearly what is contained in scripture. This is because logic alone cannot give us truth. It must start with truths that are given to it in order to make conclusions based on that truth. The bucket doesn’t put the water in the well, it gets the water that is already there out of the well. This is what logic does.

Through the process of reasoning we apply universal law in particular obedience. For example, God commands all men everywhere to repent and believe. We take this universal law and through logic apply it to particulars: You are a man, therefore you must repent and believe. If people were allowed to reject logic, they could escape the application of God’s universal law to their particular situation; that is, they could get out of obedience: “The Bible says all men are to repent and believe; it doesn’t say I personally must.”

Let’s consider more the character of God in relation to logic.

First, logic is a reflection of who God is. We see this most in Jesus Christ, “the image of the invisible God” (Col. 1:15). Jesus is the incarnate logos of God: “In the beginning was the logos, and the logos was with God, and the logos was God” (John 1:1). I am not a Greek scholar, and so I won’t take this any further than to state the obvious: Jesus Christ is the Logos, the word from which we get the word logic. In the incarnation, the infinite God became a particular Man: “And the logos became flesh, and dwelt among us” (John 1:14). The logos who was God has infinite knowledge, is infinite in power and space and time. This logos became a particular man, a man with a particular height, with ten fingers and ten toes, who could bench press a particular weight.

In a similar way, in the process of reasoning, universal statements lead to particular statements. The universal truth that all men are sinners implies the particular truth that I am a sinner. Thus an abstract truth implies a very concrete truth; “I am a sinner” is an incarnation of “All men are sinners.” It is the process of logic that allows us to make these sort of incarnational conclusions from universal claims.

What it all comes down to is that God Himself is the foundation of Reason. He is a reasoning God. “Come, let us reason together,” He says in Isaiah 1:18. According to this verse, we can reason with God, and He can reason with us. He wants to teach us, He wants to teach our students, and He uses the gift of reason in order to do so. God in His grace has given us minds that reason just as He has given us eyes that see, so that we can receive the good things that He has for us. Reason is an attribute of God, and because He is perfect in His attributes, God cannot fail to reason well. We should imitate God in this, and seek to reason to the best of our abilities. For us, this means training, learning, and study.

God is an orderly, consistent God. Paul writes that “God is not a God of disorder” (I Cor 14:33). God is orderly, and order implies reason. Where there is no reason, there is only chaos.

God is also non-contradictory: He cannot lie (Numbers 23:19), He does not deny Himself (II Tim 2:13), and He is holy – nothing in Him contradicts His perfection. John Frame says about this: “Does God, then, observe the law of noncontradiction? Not in the sense that the 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, and knowledge.”

Now, we need to be careful with this. The logic which is an attribute of God is not an exact correspondence with the logic that we study in the classroom. Logic, as an art developed by men, is (or at least can be) a true reflection, but it is only a reflection of the perfect logic of God.

Logic is not (as some erroneously believe) the science of thinking. The term “thinking” includes several operations of the human mind, many of which would fall under the domain of psychology rather than logic. But there are three mental operations which are usually associated with logic: apprehension, judgment, and reasoning.

Apprehension is the mental operation by which an idea is formed in the mind. If you were to think of a sunset or a baseball, the action of forming that picture in your mind is apprehension. The verbal expression of apprehension is called a term.

Judgment is the mental operation by which we predicate something of a subject. To think, “That sunset is beautiful” or “Baseball is the all-American sport” is to make a judgment. The verbal expression of judgment is the statement (or proposition).

Inference (or reasoning) is the mental operation by which we draw conclusions from other information. If you were to think, “I like that sunset, because I enjoy beautiful things, and that sunset is beautiful” you would be reasoning. The verbal expression of reasoning is the logical argument.

Formal logic is more properly defined as the science of reasoning. Students of formal logic analyze syllogisms to determine their validity, or develop proofs to establish a given conclusion. Logic students also learn how to define terms and make accurate statements, because these tools are necessary to learn in order to reason properly. But in so doing they are working more in the realm of informal logic, the branch of logic which is important, but which is only indirectly related to reasoning.