To spot bad arguments you often need a lot of facts. But sometimes you just need a little commonsense. When it comes to discerning truth from error, good arguments from bad, a little bit of logic goes a long way.

All of us can make strong sounding arguments that, upon closer inspection, are much less than meets the eye. We employ rhetorical strategies that look impressive (and often work) but contain hidden assumptions and flimsy reasoning. Here are six common arguments (or approaches to argumentation) that can stop us in our tracks, but are actually less impressive than they seem. These arguments are not all wrong, but they must be evaluated with discernment, and they must not be accepted without corroborating evidence.

1. The Big Nasty. One of the best ways to discredit your opponent is to give his position a nasty sounding name. No one may no what “biblicistic” means, but it sure sounds bad. Likewise, if your opponent quotes Bible verses, it’s easier to charge him with “prooftexting” than it is to deal with the verses themselves. A subset of this approach is to throw around undefined, undefended historical curse words like Platonic, Modernism, Constantine, or Gnostic.

2. The Third Way. That Isn’t. This is the perfect example of an argument that can work but doesn’t automatically. Sometimes there really is a third way. This side says Jesus is divine. These folks think he’s human. The orthodox third way says he is human and divine. That’s an appropriate use of the third way.

Similarly, most preachers have warned before against “ditches on either side of the road.” This is a variation on the third way argument. The problem is when people argue for a third way like it’s the only sane option between two crazy extremes. For example, the leadership in my denomination has frequently made this kind of claim: “Some in our midst want to push an aggressive homosexual agenda, while others want to punish everyone who disagrees with their narrow reading of Scripture.  But the vast majority in the middle realize we need room to dialogue and agree to disagree.” The problem here is that these may not be the only three options. What if there are five different approaches and your “third way” is really about the second from the left?

John Stott’s complementarian-egalitarian hybrid is another example. He paints his position as the middle ground between mistreating women on the one hand and disregarding Scripture on the other. But what if full blown complementarianism does not mistreat women? Or, the other side could argue, what if full blown egalitarianism is not unfaithful to Scripture?

3. Categorize and Conquer. Here’s another common strategy that can be worthwhile but also contains some hidden assumptions. For example, suppose you want to describe the evangelical landscape. So you divide evangelicalism into five groups (I’m just making these up off the top of my head): the new Calvinists, the neo-Anabaptists, the progressive left, the traditionalists, and Charismatics. Then you argue that we can learn something from each group. The new Calvinists teach us the importance of doctrine, the neo-Anabaptists the importance of community, the progressives the importance of social justice, the traditionalists the importance of tradition, and the Charismatics the importance of the affections. Your conclusion from this analysis: we all need to learn from each other and see the beautiful mosaic that is our diversity.

Sounds nice, doesn’t it? But while the schematic may have pedagogic value, there are a host of subtle assumptions hidden in this approach. 1) Once you’ve assigned the categories you’ve already given the strong impression that no one view is more correct than another. You sit above the whole mess and can see the parts of a larger whole. 2) The emphases in one group are not found adequately in the others. The analysis in the previous paragraph holds together only if it is assumed that each group gets one main thing right to the detriment of everything else. But what if the new Calvinists are known for doctrine and they prize the affections too? What if the traditionalists also care about community? 3) When someone puts together a categorization like this there is almost always an extra, unstated category. The hidden category is almost always some variation of “we need each other, so let’s all get along and embrace our diversity.” Of course, this could be the right answer, but its rightness must established, not assumed.

It should be noted that this line of thinking is also prevalent in discussions of pluralism and tolerance. When Christians are chastised for being intolerant of other religions what the arguer is really arguing for (though he doesn’t realize it) is that the Christian should accept his belief in the sameness of all religions and the irrelevance of doctrinal and ethical distinctions. His tolerance is not neutral ground, but an unstated faith commitment.

4. Preemptive Strikes. Any good argument will anticipate counter-arguments. But the preemptive approach doesn’t anticipate arguments, it merely tries to preempt them by defining would-be opponents in unflattering terms. So you might say something like: “I know that heresy hunters will see it as their duty to attack me.” Or, “Those who depend on the current system for their paycheck will feel compelled to cut me down.”

This rhetorical strategy is brilliant, annoying, and cowardly. Brilliant because you set a trap that no one who wishes to disagree with you can avoid. Annoying because you position yourself as a martyr before you’ve even been opposed. Cowardly because you call your opponents names even as you warn that they should not do so to you. The preemptive strike is usually passive-aggressive argumentation at its worst.

5. Affirm Then Deny. In this approach you simply say one thing and then say the opposite. “I’m not saying you’re fat, I’m just saying your grossly overweight” is an obvious example. More subtly someone might claim, “I hear what you are saying. And on one level I agree with you that God’s election is determinative in our salvation, but on another level I think God chooses us because we first choose him.” It’s possible the “levels” here actually refer to some important distinction, but often this is merely a way of saying, “I affirm your argument in principle, but now I will deny it.”

6. We’ve Been Wrong, So You Are Wrong. If you insist that God created the world out of nothing by the word of his mouth or that homosexual behavior is sinful you’re bound to have someone bring up Galileo and slavery. The argument usually goes like this: “I can’t believe you are holding to these outdated beliefs. Sure, you think the Bible is on your side, but Christians used to think the sun went around the earth, and Christians used to defend slavery from the Bible.” The idea is: “Don’t be too confident. We’ve been wrong before, so you are probably wrong now.”

I can’t recall how many times I’ve heard this line of thinking, but it’s roughly equal to the number of rainy days in Seattle. And yet for all its frequency, this argument proves nothing more than that Christians have interpreted the Bible incorrectly in the past (leaving aside whether the usual Galileo and slavery trump cards are as historically well-suited as people think). But the fact that Southerners were sure the Bible supported chattel slavery does not mean we can’t be sure of anything. In fact, the “what about slavery” argument is self-defeating because it assumes that we do know for certain that slavery is wrong. So there are things can be sure of after all.

In conclusion, all I have to say is this post was too long so I’m taking tomorrow off. The mean-spirited blog bullies will probably call me lazy, but that’s a cross I’m willing to bear. On one level this may look like a passive aggressive argument, but on another level I knew you would say that because you are beholden to Greek thinking and a mechanical dictation theory of inspiration.