Logic And God
One of the objections to studying logic most often cited is that logic does not apply to God or to any of the mysteries of the Christian faith, such as the Trinity or the Incarnation. If that were true, then logic might be of use in natural science and things in this world, but it would be useless in finding the truth about God. In other words, logic would apply to temporal, finite reality, but not to ultimate reality. Some Christians really believe this. We don’t. Why? Because even those who claim, “Logic does not apply to God,” use logic in that very statement. Logic is unavoidable.
Theology is a logos about the theos the logic of God. Theology is a rational discourse about God. The Gospel of John begins with the statement, "In the beginning was the Logos." The basis of all logic is that some statements are true and others are false. If this word about God is not a logical word, then what is it? The whole idea of theology is that rational statements can be made about God. Even someone who says the opposite has just made a rational (although untrue) statement about God. Logic is undeniable. Logic is built on four undeniable laws. There is no "getting behind" these laws to explain them. They are self-evident and self-explanatory. There is also no way around them. In order to reject any of these statements, one must assume the very principle he seeks to deny. But if you must assume that something is true to say that it is false, you haven't got a very good case, have you?
For example, the law of non-contradiction (A is not non-A) says that no two contradictory statements can both be true at the same time and in the same sense. Now, if someone tried to deny this and said, “The law of non-contradiction is false,” he would have a problem. Without the law of non-contradiction, there is no such thing as true or false, because this law itself draws the line between true and false. So we can’t call it false without assuming that it is true. The same thing happens when someone tries to deny the other laws: the law of identity (A is A), the law of excluded middle (either A or non-A), and the law of rational inference.
Theological method builds on the foundation of these elementary laws of logic. If logic is a necessary precondition of all thought, then it must also be necessary for all thought about God.
If the law of non-contradiction were not true, then theological paradox would be inevitable. We would never be able to say about God, “This is true and that is false.” Our thoughts about him would be a continuous series of contradictions without any real affirmations. Without the law of identity, theological unity would be unachievable. We would wrangle forever without realizing that we already had agreement.
Unless valid inferences can be made from what is known to what is unknown, there can be no theological argumentation. Whether in a discussion between Christians on a matter of interpretation or in a debate with a non-Christian, no one could prove any point without the laws of rational inference. These tools of the theologian are all kept in the logician's toolbox. From the standpoint of reality, we understand that God is the basis of all logic. As the ultimate reality, all truth is ultimately found in him. He has created the reality that we know and in which we have discovered the laws of logic. Even Jesus said, "I am the truth" (John 14:6). He has structured the world in such a way that these laws cannot be denied; however, we did not know God first and then learn logic from him. He exists as the basis of all logic (in reality), but we discovered logic first and came to know God through it. This is true even if we came to know God through his revelation, because we understood the revelation through logic. In the order of being, God is first; but in the order of knowing, logic leads us to all knowledge of God. God is the basis of all logic (in the order of being), but logic is the basis of all knowledge of God (in the order of knowing).
(Geisler, N. L., & Brooks, R. M. 1990. Come, let us reason : An introduction to logical thinking . Baker Book House: Grand Rapids , Mich. )
Self refuting statements:
“Be skeptical about all truths.”
“No truth can be known.”
“No statements are meaningful.”
“All truth is relative.”
“There are no absolute truths.”
Here are some common statements that are heard today that when held up to their own qualifications fall under their own weight and render themselves nonsensical [illogical] and self-defeating.