Question: “The most common grammatical error today, I feel, is the incorrect usage of ‘lay:’ people do not ‘lay’ out in the sun; I cannot go to my bedroom to ‘lay’ down; an article of jewelry cannot ‘lay’ perfectly on someone’s neck; and murder victims are not ‘laying’ on the ground. In the first three examples, the correct verb is ‘lie,’ and the final example should have murder victims ‘lying’ on the ground. I can, however, ‘lay’ my books on a table and a hen can ‘lay’ eggs. I recommend an article on the correct usage of the verb ‘lie’ sometime soon because I hear it misused on national and local TV and radio broadcasts and, incredibly, read these errors in print.” (Mrs. Theodore (Marcia) Esping)
Answer: Well, it sounds like you’ve already got this rule down, but I’d be happy to lay it out for other readers.
Let’s start off in the present tense. Things are fairly cut and dry here. “Lay” means to put or set an object down. Note the word “object” there. In the present, “lay” always requires an object: I lay my head down; you lay down the phone; we lay down our swords.
To “lie” is to be or stay at rest in a horizontal position. Thanks, Merriam-Webster. It’s also a homonym to “lie,” to tell an untruth, which may be what gets some people confused. In the present, and all of its conjugations, “lie” requires no direct object: I lie down; the cat lies on the floor; you lie on the bed.
As we get into the past tense, though, things get a little trickier. In the past tense, “lay” becomes “laid,” and “lie” becomes… “lay.” It’s sadistic, I know. So, while yesterday you “laid” down your sword, the cat “lay” all day on the floor. “Lay” remains “laid” in the present participle (“It was only yesterday that we had laid down our swords.”) while “lie” becomes “lain” (“The cat had lain on the floor all day until I got home.”). The present participle of each verb may be the simplest transition of all: “lay” becomes “laying” and “lie” becomes “lying.” I am lying down for a nap. She is laying the phone down.
Remember: “Laid” and “laying” always mean to set something down. “Lie,” “lain” and “lying” always mean to be at rest (or to set yourself down). Only “lay” can mean both. So when you think you need to use lay, ask yourself: Am I setting an object down, and am I speaking in the present tense? If the answer to both questions is “yes,” use “lay.” Otherwise, only use “lay” when an object is at rest (or setting itself to rest) in the past tense without a helping verb. And if you’re talking about potato chips, use “Lay’s” (although Doritos are better).