I received some surprising feedback lately from a fellow Christian pushing back against my emphasis on logic. The charge was even made that I “idolized” logic. Surprising (and saddening) as this is, I suppose it is worthwhile to review the role of logic in our lives. Now, I would never want to put anything, even logic, before God, but the simple fact of the matter is that we really can’t know God without logic. Don’t believe me? Let’s dig into that today by looking at 3 questions: What is logic? Is it necessary? And how does it apply to our understanding of God?
- First, what is logic? Is it some mysterious type of thought used by Vulcans, Mentats, and computers that is antithetical to Christianity? Hardly. Logic is to thought as grammar is to language; it is the structure of thought. Logic is simply the organization of our thoughts into coherent structures that can have discernible meaning. Without any further clarification, the statement “I am 5 feet tall and 6 feet tall”, would be nonsense to you. You might ask if I meant that my height was between those 2 numbers, or if I was talking about at different times of my life, or you might ask what the punchline was. Why would you not just accept that I existed in the form of 2 different body heights at the same time? Because it’s not possible. And we have a law in logic that puts that common sense notion into words. The law of non-contradiction states (in Aristotle’s formulation), that “the same property cannot both belong and not belong to the same subject at the same time in the same respect.” To have a body height of 5′ and 6′ at the same time, measured the same way, would necessarily be a contradiction and would be physically impossible. Because we cannot conceive any way something physical could be 2 different lengths at the same time in the same way, contradictions like that are truly nonsense. Now, it’s not like Aristotle (or anyone else) invented the laws of logic, anymore than Newton or Einstein invented gravity; these laws simply describe relationships that already exist. Logic is not a human invention, just a human discovery.
- Is logic really necessary? As Peter Kreeft points out in the preface to his logic textbook, “We all have used logic already, unconsciously, many times every day.”  He goes on to say, “One of the best remedies for bad reading and writing is good logic.”  Another professor laments that “logic is the very backbone of a true education, and yet it is seldom taught as such in American schools.” While philosophy professors may bemoan the lack of logic instruction outside of their classrooms, that alone doesn’t make it actually necessary. In fact, you can certainly think without knowing logic, but only in the same way you can speak and write without knowing grammar – in both cases, the results will not be as coherent. Of course, the basics of logic, like the rather obvious law of non-contradiction, are what we tend to call “common sense”, so even without knowing logic, it’s hard to not use it, even if used poorly at times. In fact, one typically has to resort to logic in any attempt to argue against it.
- So how does logic fit in with knowing God? Classical logic systematizes our thoughts into three acts of the mind: understanding, judgement, and reasoning.
- Understanding (or simple apprehension) is where we define our terms, where we understand what it is we are thinking about. When we say that “God is good,” what do we mean by the terms “God” and “good”? Many an unnecessary argument rages on because two opponents use the same terms but mean different things.
- Judgement is that act of the mind where we make truth claims that must be accepted or rejected.Once we have our terms defined, judgement is what we say about those terms, those objects of our thoughts. We think about God, and judge that He is good. Our judgements are statements that are either true or false. There is no middle state between true and false, existence and non-existence, or any other condition and its negation (this is called the law of the excluded middle). If there is a middle option, then we have not been sufficiently specific in our initial statement.
- Reasoning is where we establish why our judgements are true. This is the justification, warrant, or basis, for our statements or beliefs. Why do we think God is good? Think of valid reasoning as the foundation stones that support the structure made from true judgement of clear terms. Without valid reasoning, you can be accidentally correct about something, but your belief is just a house of cards waiting to be knocked over. Too many people rightly believe various truths about God, but for reasons like how it makes them feel, or that their parents told them these things. If they never dig any deeper to the real foundational reasons, then they are easy prey for the first skeptic that comes along and knocks these false supports out from under them.
Logic clarifies what is believed, deduces the necessary consequences of the belief, and applies it to difficult situations. Let’s look at a prime example: the Trinity. This is core Christian doctrine. Indeed, it’s been said, “In the confession of the Trinity throbs the heart of the Christian religion: every error results from, or upon deeper reflection may be traced to, a wrong view of this doctrine.”  So why do we believe that God is triune? Because the church fathers had to wrestle with the tension between the clear teaching in the Bible regarding three divine Persons, and the equally clear teaching that the Lord our God is one God. But they very laboriously worked through precisely defining terms, judging what were true statements about those terms, reasoning through the serious implications of what they knew to be true, and applying that logic to discover this truth about the nature of God that we call the Trinity. The Trinitarian formulation is the result of resolving a paradox through logical reasoning.
As Professor Kreeft points out, the simplest and most important reason for studying logic is that “logic helps us to find truth”.  Jesus tells us in John 14:6 that He is “the Way, the Truth, and the Life.” Any tool that draws us closer to truth can draw us closer to Him. And that’s worth defending.
 Peter Kreeft, Socratic Logic (South Bend: St. Augustine’s Press, 2010), p. 12.
 ibid. p140.
 D.Q. McInerny, Being Logical: A Guide to Good Thinking, (New York: Random House, 2005), p. ix.
 Kreeft, p. 4.
 Herman Bavink, The Doctrine of God, p.285, as quoted in Wayne Grudem, Systematic Theology (Grand Rapids: Zondervan, 2000), p. 247.
 Kreeft, p.7.