This is a heartfelt study of reason and human rationality, and other related things. It's a 'meta-study' that personally fascinates this author! Why are humans rational beings? Why is there logic and other kinds of order? Why is there intelligibility?The self-evident existence of reason, logic, and intelligibility are strong evidence for God. Reason is an undeniable human faculty that defines humanness and points to a rational universe. This in turn points to the principle of reason, or the logos developed by Heraclitus and other Greek philosophers, and later by the Apostle John. Reason and its corollaries emerge like aspects of language and complement each other like speaking and listening. Indeed, mutual communication works because of reciprocity, which is a root form of intelligibility. This seems to be the structure or order which is best explained by a rational, divine Mind that exists eternally in reciprocal complementarity.This, then, is an exploration of the role of the Logos principle in the human experience and condition we often refer to as Reality. It is an attempt to answer these four questions and others related to it: Why do reason and logic work?Why do we believe and trust in them?Why do we expect things to make sense?Why does anything make sense at all?First I talk about reason as an indispensable part of every person's daily life. It is a vital element of human functionality and part of what defines humanness. For example, many people value education and spend a lifetime trying to expand their powers of reason. But nobody deliberately tries to decrease them, not even people who claim to rely on faith. The first part of this book will touch on the relationship between reason and faith, but it is primarily concerned with reason, and logic its foundation. As with reason, how do we explain logic? Is it arbitrary? Did humans invent it?We humans depend on reason every day. We use it to function in both basic and complex ways. We cannot see reason, but like other invisible things, we don't have to. We can know reason is real when we see it in action in our own minds and in others' behaviors. We can 'hear' reason when people talk and relate to each other, when they study and discuss things aloud. We can observe people making decisions (good and bad) and living out the consequences (good and bad). We can see this happening when people are doing their jobs and all kinds of tasks. On a personal level, we can be aware of and reflect on our own reasoning when tackling life's problems and their possible solutions, comparing the options and their possible outcomes. In short, we can reason about reason, and reflect on its quality. And it is impossible NOT to reason.This leads to the book's main argument: Because reason exists, God exists. It's not that through our powers of reason we can be certain of the existence of God, but rather that the existence of reason and its corollaries point compellingly to God.This is largely a philosophical argument, but philosophy and theology overlap. So in the sphere of religion, reason is also an essential tool for thinking about faith, especially at scholarly levels. Contrary to what some non-theists believe about theists, many religious people do think seriously about faith, which is reasoning. Faith is not the suspension of reason, nor must it be 'blind' to qualify. It shouldn't be. Even simple faith has reasons attached to it, and anything that has reasons involves the use of reason. Faith, in part, is the application of reason to metaphysical questions and propositions. So theists must apply reason when thinking about God (even if he might not actually exist). Therefore, in moderate terms he probably does exist, and there are ample reasons for confidence that he does, including reason and logic themselves. Add to these intelligibility, order, reciprocity, and another concept that becomes very prominent toward the end of the book-complementarity