In this post and many others I will talk about linguistic phenomena that I’m sure are well documented, but of which I’m sadly ignorant. If you have an explanation for something I’m wondering about or know of any good references, please let me know!
Lately around campus there have been a lot of signs encouraging me to “Close your hood sash when not in use!” I do not know what a hood sash is, exactly – I believe it is some sort of equipment that chemists use – but I do know that the signs are telling me to close the sash when the sash is not in use, rather than when I am not in use. That’s interesting. Consider the following sentences:
- “Close the hood sash when not in use.”
- “The robot closes the hood sash when not in use.”
- “Birds collide with the plane when flying.”
- “Collide with the plane when flying.”
In #1, “when not in use” clearly refers to the hood sash. Syntactically, my judgment is that it could also refer to the subject, but that meaning would sound very strange. In #2, however, the phrase could refer to the hood sash or the robot, with a slight preference for the robot. For #3 I have only a slight preference for “when flying” modifying “birds” rather than “the plane,” but I have a strong preference for interpreting #4 as “Collide with the plane when you are flying.”
What’s going on here? In many cases, the meanings of the words themselves may force a particular interpretation. Perhaps #1 can’t be interpreted as “when you are not in use” because it’s unclear what it would mean for the subject of the sentence, who is presumably a person, to be “not in use.” In #2, the subject is explicitly identified as a robot, and since it’s easier to imagine what it means for a robot to be “in use,” both interpretations become viable.
Looking at only 1-3, one could conceive of a simpler explanation: “when not in use” can refer to any noun phrase that appears explicitly in the sentence; since the subject in #1 is implicit, the interpretation “when you are not in use” is not prefered. That reasoning falls apart when applied to #4, though. My theory is that any interpretation that doesn’t conflict with the meanings of the words in the sentence is viable, but that it is always somewhat preferable to interpret a phrase like “when not in use” as refering to the subject of the sentence.
This probably is nothing deep, but it has me puzzled.