A qualifier is any word or phrase that provides a “reference point” for a claim. Knowing how to use them can both increase the strength of an argument and shield it from attacks. English is full of qualifiers for different situations. They’re generally divided into two groups: absolute and relative.

Absolute qualifiers say something conclusive about a subject. They include words such as always, never, all, none, you must, I know, best, worst. In each of these cases, the assertion is unwavering, complete. When you say “Mike never makes it up that hill,” you’re leaving no space for fault. If Mike gets to the top of the hill at any point in his lifetime, you’ll be wrong.

Relative qualifiers, on the other hand, are more flexible. Words like sometimes, usually, most, less, I think, you might, better, and worse are common examples. Here, the assertion is less powerful, but more likely to be accurate. If you say, “Mike usually doesn’t make it up that hill,” then you’re not necessarily wrong if he gets to the top next time. As long as he fails more times than he succeeds, your claim is solid.

Absolute qualifiers have a sort of alluring energy behind them that can be useful in certain circumstances. Saying “we know there are weapons of mass destruction in Iraq” is a lot more convincing than saying “we think there are weapons of mass destruction in Iraq.” Most of the time, though, it’s best to avoid using absolute qualifiers, because they put you in an all-or-nothing situation that can be difficult to defend.

Relative qualifiers, if chosen carefully, can be incredibly helpful. They provide a context for your message that eliminates enough fuzziness so that your point can’t be misunderstood, but don’t box you in so much that you’re unable to account for situations that might otherwise contradict your argument. That way, if you say, “most young boys prefer to play with other boys,” and someone shows you a boy who plays with girls, you can respond by referring to your qualifier: “I said most, not all. Of course there are exceptions.”

Use your qualifiers recklessly, and you’ll go down faster than a certain infamous boat that could “never sink.” Use them wisely, and you’ll have smooth sailing.