Classical logic provides the basis by which we assess the external world in our daily lives.  For example, either today is your birthday or today is not your birthday.  Either Easley, South Carolina is your current physical location or it is not.  Either the mass of your body is 80 to 81 kilograms at this moment or it is not.  On a more abstract level, classical logic provides the foundation for all program control expressions in computer source code; Boolean expressions evaluate to zero if false and one if true. 

A belief that classical logic represents reality was pervasive throughout not just Christian but all civilized thought until the 19th century.  Then the philosopher Hegel alluded to the possibility that we need not assume true/false should always be assigned to a thesis and its antithesis.  Instead we can attempt to synthesize, by reason, a higher concept closer to actual truth.  This proved to be impossible by any logical process but later, the theologian Kierkegaard proposed that logic could be abandoned altogether when dealing with propositions involving God or attributes of the human soul. When dealing with such matters, the synthesis could instead be attained by a "blind leap of faith" unsupported by any type of logic. 

For example, a choice, based on evidence, between (Jesus is God) and (Jesus is-not God) is demanded by classical logic.  However, using this new way of thinking, other options may be synthesized such as "Jesus can be God for some but not for others because truth is personal" or "I believe Jesus is God based on my feelings, intuition and emotions but cannot support this belief by any form of logic or reason based on evidence".  This new way of looking at "truth" permeates the civilized world and may be the most crucial problem facing Christianity in this century.  Philosophy, art, music, the general culture and, to some extent, Christian theology have embraced it.  

In contrast, historic Christianity stands on the beliefs that classical logic represents the "truth of God" and sound reason is the foundation of the Christian faith.  John Wesley, for example, placed reason at one corner of his "quadrilateral" which serves as the cornerstone of Wesleyan theology; reason based on the evidence of Scripture, tradition and personal experience should serve as the basis of the Christian faith.  The Christian God is a God of absolutes and one of His attributes is "truth."  Since we are created in His image, " absolute truth" is knowable and can be distinguished from "absolute lie." If you reject the use of classical logic in religious thought or some other area of your life then, in that area, truth is personal, situational, relative or unknowable and that area of your life will be a perpetual source of confusion and despair. 

Should Christians address this issue or concentrate on more "spiritual" things?  Perhaps Martin Luther answered that question several centuries ago:  

If I profess with the loudest voice and clearest exposition every portion of the truth of God except precisely that little point which the world and the devil are at that moment attacking, I am not confessing Christ, however boldly I may be professing Christ.  Where the battle rages, there the loyalty of the soldier is proved, and to be steady on all the battlefield besides, is mere flight and disgrace if he flinches at that point. 

Finally, some issues are central to Christian theology while others are peripheral.  Chapters 7 – 10 deal with central issues while chapters 1 – 6 address peripherals.  Failure to acknowledge the truth about a peripheral issue does not imply a person cannot be called Christian.