The other night on twitter, I went on a mini-rant about the difference between fewer and less. There are quite a lot of commonly confused word pairs such as those, and almost instantly, people started asking for tips on how to remember other correct usages. Longtime friend of the blog Ian Healy asked for tips on lay and laid, but instead of tweeting it, I thought I'd better do a blog post. This one doesn't lend itself to 140.
Everyone mixes up lie/lay and lay/laid. Even the most meticulous authors can fumble this one from time to time, and the main reason for the confusion, I think, is that the past tense of "to lie" is lay, which is also, of course, the present of "to lay." So you have the same term used both transitively and intransitively in different tenses, and the meanings are so close as to be nearly indistinguishable. Yay, English! Good choice on that one!
Right. Let's break it down.
To Lie (intransitive - no object)
Present - Lie
Past - Lay
To Lay (transitive - object)
Present - Lay
Past - Laid
The main difference between the two is whether they take a direct object. This is where the children's prayer in the title of the post comes in handy.
Now I lay me down to sleep...
The three most important words here are now, lay, me.
Now -- it's the present tense.
Lay -- this is the confusing verb we're trying to sort out
Me -- the direct object.
So in the present tense (now), the verb lay takes a direct object.
If you used the other verb, it would have to be revised to:
Now I lie down to sleep...
Two hours ago, I lay down to sleep...
(past tense, no object)
Two hours ago, I laid the baby down to sleep, and please God, make him quit crying...
(past tense with an object)
But that's not what the prayer says. Now I lay me down to sleep, etc. If you remember that, it will help you remember the difference between lie and lay. Even so, I have a grammar page bookmarked (the Purdue OWL, because, you know, Boiler Up! etc.) so that I can check it when I need a refresher.