To lie means to assume a prone position (and to prevaricate); to lay means to place or set. So you should say, "Lie down here, and lay [or set] your phone down there." Think of the lyrics in Bob Dylan's classic song, "Lie, lady, lie." (I'm sure he sang lie, not lay. Please correct me if I'm wrong.) And as a friend once reminded me, it's lie low, not lay low.

It may help you keep the two words straight if you remember that lay is usually used with an object. To lie in the warm sun feels good, but to lay your hand on a hot burner does not.

So why do so many people, educated and uneducated alike, say lay when they mean lie? I believe there are three principal reasons for this egregious erratum.

First, the error is pervasive, and you tend to repeat what you hear, so even though you were taught to say, "Lie back on your mat," you may catch yourself saying, "Lay back on your mat."

Second, as a child you may have been taught a bedtime prayer that begins, "Now I lay me down to sleep." Here the verb is correct (though the pronoun is wrong). Note that "Now I lie down to sleep" is also correct, as is "Now I lay myself down to sleep," but those versions aren't nearly as pleasing as the trochaic metered line, "Now I lay me down to sleep," that runs through your head. Remember, you lie down (or assume a prone position) and you lay (or place, set or put) something down. In the case of the bedtime prayer, you are laying yourself or "me" down, so lay is correct.

Third, and here's the real doozy, lie and lay are confusing because the past tense of lie is lay. Now I ask you, is that fair? I mean, shouldn't there be a law proscribing confusing word pairs and prescribing correct word choice, such as flaunting your intelligence and flouting the rules? On principle, shouldn't the principal meaning of a word be apparent by its appearance?

So why make the effort to say lie when most people say lay? Two reasons.

First, people who don't know the difference either won't notice or don't care. Second, people who do know the difference feel a sharp pain in their ears every time they hear lay when it should be lie. They also think less of the speaker (or writer). For example, what would you think if just before removing a tumor from your cerebral cortex your surgeon said, "Now if you feel any dizziness after the operation, just lay down"?

Lie down. Lie down. Lie down. Yesterday, I lay down, but today I will lie down. Say it with me. Lie down. Lie down. Lie down.

Stephen Wilbers offers training seminars in effective business writing. E-mail him at wilbe004@umn.edu. His website is www.wilbers.com.