That raises an interesting question: at what point should we give up on a distinction and call it a lost cause? Does it make a difference if the distinction isn't helpful or productive?
After all, the only difference between
lay and
lie is that the first is causative (something causes something else to start doing something) and the second is inchoative (something starts doing something). And there are plenty of verbs in English that can be either causative or inchoative, like
cook or
melt.
For example:
- I cook the meal.
- The meal cooks.
- I melted the butter.
- The butter melted.
But for some things, you need two different verbs:
- He lays the book down.
- He lies down.
- He set the book on the shelf.
- The book sat on the shelf.
So it's not like we're really gaining anything by having two different verbs when one could easily be used for both notions.