God establishes reason, and without Him, we do not have reasons for reasons.
We reason by the laws of logic combined with facts we observe. For example, the Law of Non-contradiction, that A cannot be both A and non-A at the same time and in the same relationship. These abstract, conceptual principles must be accounted for if any discussion on any topic is to take place. Only the Christian God can account for these laws. His thinking upholds ours.
If the laws of logic are based on human thinking, then we have to realize that people are different and the laws may differ from person to person. They are no longer absolute. Some particular examples follow.
If the laws of logic are just social conventions, then they are not absolute, and they can be ignored at will. My social network is, after all, different from yours.
How do we avoid the conclusion that all of our thinking is not the result of mere instinctive reactions to our environment? Since our environments are all different, we would all reach different conclusions. We would have no basis for argument because we could not change each other’s minds because we could not change each other’s environments to the degree required.
If our thinking is a preconditioned response determined by our genetics, rational impulses would then be determined by genetics. There would be no decisions made in any traditional sense. We would all be pre-programmed to do what we do, and therefore there would be no sense in arguing. We could not change each other’s genetics, so no one could possibly win. Anyone who argues a point assumes that logic applies and genetics don’t determine our thinking if they are consistent.
I guess that our thinking could be based on the consequences of our actions (e. g. behaviorism in psychology). But then we would have to wrestle with the inconsistency of consequences, especially soon, certain and positive consequences. That would make thinking inconsistent from person to person. Not to mention that now all that could win an argument would be a form of force, since only superior force can fix consequences for others. Survival of the fittest indeed!
The laws of logic cannot come from science because science is based on inductive reasoning from things we see in our environments. For example, we cannot see the law of non-contradiction in the world. We would have to see the properties of a non-existent things (non-A). The laws of logic are abstract constructions that exist only in the mind. We discover the laws of logic by thought, not observation.
The laws of logic are also undeniable. If we say, for example, “I know the laws of logic do change. We’ve found scientific discoveries in quantum physics that disobey those laws.”
Nothing that is expressed in words disobeys the laws of logic. Any discovery you make must be logically understood. For example:
If the Law of Non-contradiction (A cannot be both A and Non-A at the same time, in the same relationship, and in the same sense) is not in effect, then you might as well say to me: “We’ve found scientific discoveries in quantum physics that obey the laws of logic.” “Obey” and “disobey” can have the same meaning in your sentence.
If the Law of Identity (something is what it is, something that exists has a specific nature) is not in effect, the discovery in question would not necessarily be a discovery. Your statement of the discovery could be: “We’ve found scientific discoveries in quantum physics that disobey those laws, but the discoveries changed into discoveries which followed the laws of logic when we came back the next day.”
If the Law of Excluded Middle (a statement is either true or false) is not in effect, your statement on quantum physics could be false even if it were true.
None of the sentences used by anyone would have any objective meaning if the laws of logic do not apply. If the laws of physics as they are currently understood do not apply, it does not follow that the laws of logic do not apply. This would go for any recent scientific discovery. As soon as a person opens their mouth to refute logic they have assumed it.
If Christians are wrong, we are left with no reason to think that we can have rational discourse. Atheists and agnostics cannot have an argument, because they do not have a position.
Why do I think that only the Christian God among other gods can ground logic and other immutable laws? Short version:
Islam postulates a God whose idea of morality changes from this world to paradise (e. g. monogamous sex now vs. promiscuous sex with the virgins in paradise). His moral laws change and are not absolute.
Judaism postulates a god very much like Christianity’s, but the Jews’ God does not forgive based on an adequate atonement (The infinite Christ does not pay the penalty for their sins by suffering all of God’s wrath). If he forgives, his standards are not unchanging.
The god of the process theologians and / or open theists changes himself as time goes on (e. g. he learns things about the undetermined future). He cannot then be the ground of anything like the laws of logic, which do not change.
A finite god who came into being (this is really what a person is saying if they say God had a cause) would be ruled out as well. If God came into being, that would be changing. He could not be the ground of the laws of logic because logic requires an unchanging ground.
Deism does not allow for a God who interacts with His world. The laws of logic would have to be inherent in the universe he made. The universe we live in changes constantly, therefore the laws of logic would change with the universe.
Pantheism, the idea that god and the world are the same in their being, also falls short. In this god is all and all is god. The universe shows it changes. The unchanging laws of logic force us to assume that an unchanging God exists, so the universe must be different from God.
Gnosticism’s god is irrational and illogical as defined by most expressions of that religion. However, I realize that not all forms of Gnosticism are alike.
If any of the worldviews that oppose Christianity are true, we have no reason to think that we can have rational discourse. We cannot even have an argument, because none of us has a position we can communicate.
In the case of atheism, this also shifts the burden of proof from the Christian to the atheist. Now the atheist must put forth a justification for logic and reason before we must hear him. This is a significant thing because atheists are used to tearing down arguments, not making them.
Please keep in mind that we are to pray for God to bless all of those we engage in this conversation. We should pray for their protection from harm and repentance to life. The only difference between them and us is the unmerited favor of a loving God. We cannot ‘look down our noses’ at them since we once “lived” among them.
(Sources for the above are: John M. Frame, The Christian Apologetics and Research Ministry, and Tearing Down Strongholds: And Defending the Truth by R. C. Sproul, Jr. Of course, the mistakes are all mine.)
By the way, this is my first attempt to use any form of the transcendental argument from logic. If you have a critique or a suggestion, please let me know.