Last-Antecedent Canon. A pronoun, relative pronoun, or demonstrative adjective generally refers to the nearest reasonable antecedent.
Series-Qualifier Canon. When there is a straightforward, parallel construction that involves all nouns or verbs in a series, a prepositive or postpositive modifier normally applies to the entire series.
Nearest-Reasonable-Referent Canon. When the syntax involves something other than a parallel series of nouns or verbs, a prepositive or postpositive modifier normally applies only to the nearest reasonable referent.
At the end of the post, I raised the question whether the preferences stated in these canons can be justified on purely linguistic grounds—i.e., whether they represent “valid generalization[s] about how expressions in English are understood[.]” I’m going to try to answer that question here.
This post is a long one, so let me say up front that the verdict on these canons is a mixed one. The good news is that in some categories of cases where these canons apply, there is in fact a linguistic justification for applying them, by which I mean that in those applications the canons more or less parallel one of the recognized tendencies in how people process and comprehend sentences. (The same parallel applies to the rule of the last antecedent as it’s generally applied by the courts, which differs somewhat from the Scalia–Garner version).
Now the bad news. First, the processing tendency that I’ve referred to is just one of the factors that influences how a given sentence is understood, and other factors can exert an influence in a different direction. So even in cases where the canons are consistent with this processing tendency, it’s hard to say in advance whether applying the canons would result in a linguistically justified interpretation.
Second, in the canons’ other applications, I don’t think there is the same parallel between the canons and the kinds of processing tendencies that I’ve referred to above. And more than that, in a large subset of those applications, the canons are actually inconsistent with what the literature on processing tendencies would predict. In those applications, therefore, there is reason to think that applying the canons would result in interpretations that are linguistically unjustified.
On to the details.