An awful lot of people seem to use the phrase "substitute X for Y" to mean "replace X with Y", while I've always used and understood it as "replace Y with X". This makes sense to me, given that a substitute is the replacement, not the thing which has been replaced.
I thought I might be able to figure things out from a dictionary, but now after seeing two sorts of definitions, I'm even more confused:
- to put or use in the place of another
- to take the place of; replace
The first one suggests that the object will be the substitute (replacement), the thing put into place, while the second suggests that the object will be the thing which has been replaced.
Is one of these usages more correct in any sense? (I know this is probably a pointless question, since people will continue to speak the way they speak.) Is there perhaps a difference between American and British English?
And most importantly, is there any reliable way to tell what someone means when they ask how to substitute honey for sugar, or is the verb simply guaranteed to cause confusion?
Best Answer
This is probably the source of the confusion you noticed:
“Substitute…for…” is an unusual case when it comes to the order of this sort of phrase, but actually the preposition is all-important. Just think of for as meaning in favour of or in place of.