Tag Archives: Reason

Columbo’s Logic, Part 2

Recommended reading for clear thinking

Last week, we looked at Greg Koukl‘s classic book Tactics, and how his first “Columbo question”, “What do you mean by that?”, is an application of what’s called the first act of the mind in philosophy. This first act, understanding, is simply recognizing that we have to understand what we’re discussing before we can even hope to be able to decide if it’s true or not. His next critical question to ask is “How did you come to that conclusion?” While the first question addresses the what, this one addresses the why. This serves a couple of purposes: First, the person you’re talking to may have good reasons for holding the position they do, that you hadn’t thought of before, and this gives them the opportunity to share those. But secondly, it places the burden of proof where it belongs – on the person making the claim. As Greg points out, “an argument is different from an assertion… An assertion simply states a point. An argument gives supporting reasons why the point should be taken seriously….”[1] Yet many people haven’t thought through why they hold a certain position. Too often, it’s easier to sit in an echo chamber and not dialogue with people of opposing views who may challenge one’s views and legitimately ask for reasons for the claims made. But this question graciously gives your conversant the benefit of the doubt that they have thought about their position and actually have good reasons for why they hold their view. If they have, now’s their opportunity to convince you. If they haven’t, it can hopefully be a wake-up call for them to examine their beliefs. With that in mind, let’s think about the act of reasoning.

This “third act of the mind”, reasoning, is what allows humans to acquire  knowledge beyond our particular experience, and to abstract from particular truths to universal and/or necessary truths. Reasoning is also where we justify our claims by providing valid arguments. As I mentioned last week, the terms we use, by themselves, can be clear or unclear, but they can’t be true or false. Neither can our arguments; they can only be valid or invalid. What is validity? Peter Kreeft, in his Socratic Logic textbook, defines it thus: “An argument is logically valid when its conclusion necessarily follows from its premises.”[2] He further explains:

“Validity is a relationship between propositions: between the premises of an argument and the conclusion of the argument…. A valid argument gives us certainty about its conclusion. It is not absolute certainty but relative certainty, that is, certainty relative to the premises… certainty that if the premises are true, then the conclusion must be true.”[3]

Validity is the mechanical aspect of reasoning that allows us to know two specific relations between a conclusion and its supporting premises: when a conclusion must be accepted, and when a premise must be rejected. Let me explain. Sometimes, a case is being constructed in front of us, and we can follow the steps from defining the terms, to making statements about the terms, to “connecting the dots” with valid reasoning. In this case, a valid argument built on clearly-defined, true supporting premises will have a true conclusion. There is no other possibility given those three conditions. But oftentimes, we are simply presented with an assertion. This is the scenario Greg addresses with the Columbo tactic when he asks someone to clarify their terms and give their reasons that (hopefully) transform their assertion into a conclusion. He is working backwards, deconstructing the conclusion to check its foundation. And in this scenario, a valid argument with a conclusion known to be false guarantees that at least one of the premises is false. The validity of the reasoning isolates the problem to the premises. Kreeft likens this forwards or backwards reasoning process to following a river from its unpolluted source to its unpolluted conclusion downstream, or tracing pollution downstream back to its polluted source upstream.

These two acts, understanding and reason, are two necessary steps toward the end goal of truth. But truth is only conveyed in propositions, whether that be the supporting statements or the final conclusion. To judge the truth of those statements, we need to look next week at the 2nd act of the mind… judgement. Until then, here’s a little homework: next time you’re in a discussion with someone who holds a different view, politely try asking them for the reasons they hold that view. In the absence of any opportunities like that, examine the foundations for your own views. Are they sound? As Greg says, “Intelligent belief requires reasons”[1], and that is true for Christians, atheists – everyone.


[1] Gregory Koukl, Tactics: A Game Plan for Discussing Your Christian Convictions (Grand Rapids: Zondervan, 2009), p. 60.
[2] Peter Kreeft, Socratic Logic (South Bend: St. Augustine’s Press, 2010), p. 31.
[3] ibid., p. 194-5.

The Challenge of a False Dilemma

Wall St BullSometimes as engineers, we are confronted with tough choices like counteracting project requirements; solving one problem makes the other worse, or vice versa. My boss gave me some good advice in these situations: redefine the problem. Often, the problem is not one of truly conflicting requirements, but rather of our presuppositions leading us to interpret the requirements a certain way, eliminating valid options prematurely (or more likely, never even considering them).

In many areas of life, we are likewise confronted with dilemmas where neither choice is desirable. The two unwelcome choices of a dilemma have long been compared to facing down the horns of a charging bull: but is it only a question of which horn you want to be skewered on? Not necessarily.[1]

The first step with any dilemma is to see if the choices offered are mutually exclusive and exhaustive. That will determine whether or not we are really limited to the choices given, or if we can “escape between the horns” of a false dilemma.  This is like my boss’s idea of redefining the problem. This is the easiest solution, but it may not always be possible, especially if the dilemma is carefully worded. For instance, consider the dilemma “He who is not with me is against me.” This is mutually exclusive and exhaustive (the way this is worded, a person trying to claim neutrality is lumped in with those in the “against” category; thus the case of x or non-x exhausts the possibilities, and the two are contradictory positions that can’t be held at the same time in the same manner, thus being exclusive).[2]  If there are other options not stated, or if we’re not limited to an either-or choice (maybe both options or neither apply) , then it’s not truly the dilemma it was made out to be. For example, suppose your friend Joey asks you if hamsters should have legal rights, and on answering, you’re given the dilemma “If you don’t agree with me on this issue, you’re either a bigot or an idiot!” While it may be a childish response,  it’s still an example of a dilemma, but one that definitely doesn’t exhaust the possibilities; the idea that Joey could simply be wrong and your opposing view perfectly warranted is still a viable option.

What if we really are obligated to the dire options given? Then we need to look at the choices themselves to see if the conclusions are true. This is called “taking the dilemma by the horns”. Invalid reasoning, false premises, and ambiguous terms can break one or both horns of the dilemma. Suppose we accept Joey’s conclusions of bigot or idiot as the only possibilities. Are those really the necessary result of disagreeing with him? Most bad arguments won’t actually have invalid reasoning. Even Joey’s response is still logically valid – if his assumptions are true. First, let’s look at those. In other words, what is he assuming connects disagreement with bigotry and idiocy? Filling in those unstated premises, his dilemma would look more like this: “If you disagree with me on this, then either A) you are a bigot, for all who disagree with me regarding hamster rights are bigots, or B) you are an idiot, for all who disagree with me on this are idiots.” If his terms are appropriate, and these premises true, then his either-or conclusion would be valid. But “all” is actually a pretty big word in each of his assumed premises, as that implies that disagreement with him somehow consistently results in reduced mental capacity or unfair intolerance in other people. Unless he could clarify that, this premise appears to be false. This brings us to the most common cause of false conclusions: ambiguous terms. The term “bigot” means someone with an obstinate and unfair intolerance of opposing ideas, and so it does not follow that you are a bigot simply for having an opposing idea. In this case, Joey is probably using “bigot” ambiguously to begin with, which makes his first premise false once we correctly define the  term. It’s important to remember that refuting an argument doesn’t prove the conclusion to be false. You might still be a bigot or an idiot, but your friend will have to come up with better reasons to prove that.

Of course, Joey the Defender of Hamsters was a somewhat silly example, but the concepts apply to any dilemma (or any other disagreement) you might find yourself in. Remember: define the terms clearly so you understand the issue; judge whether the supporting reasons are true;  determine whether the conclusions necessarily follow from those reasons; and with dilemmas specifically, determine whether the conclusions offered are really the only ones available. Tune in next week as we apply this tactic to a more complex dilemma, an argument against the goodness of God called the Epicurean Dilemma.


[1] See Peter Kreeft’s “Socratic Logic” textbook, (St Augustine’s Press, 2010), Ed. 3.1, p. 306-310 , for a more technical analysis of constructing and responding to dilemmas.
[2] Matthew 12:30, NASB. This quote from Jesus uses the Law of the Excluded Middle and the Law of Noncontradiction, and is a sobering warning to those thinking they can be neutral toward Jesus, or think of Him as “a wise teacher” and nothing more.