I'm proofreading a text that includes the following passage:
Semiology is defined in A Glossary of Literary Terms as ‘the systematic study of signs, as these function in all areas of human existence’. So perhaps this is what all modern literary and artistic study is.
It's the second sentence I'm having trouble with, particularly the phrase, "what all modern literary and artistic study is."
I can't decide whether that sentence should end with "is" or "are". If I were editing, I would just rewrite the sentence, but I don't have the remit to do that as a proofreader.
A compound subject linked with the word "and" would normally take the plural:
"…what all modern literary [study] and artistic study are."
But neither "is" nor "are" sound correct to me.
I'm assuming that it is a compound subject in that it is referring to two types of study (literary study and artistic study) rather than a single subject (study that is, at the same time, both artistic and literary).
Is this a compound subject, as I'm assuming it to be, or a single subject? Or is there a better way to think about this problem?