As I said in my last post, I don’t think the distribution of that and which is adequately explained by the restrictive/nonrestrictive distinction. It’s true that nearly all thats are restrictive (with a few rare exceptions), but it’s not true that all restrictive relative pronouns are thats and that all whiches are nonrestrictive, even when you follow the traditional rule. In some cases that is strictly forbidden, and in other cases it is disfavored to varying degrees. Something that linguistics has taught me is that when your rule is riddled with exceptions and wrinkles, it’s usually sign that you’ve missed something important in your analysis.
In researching the topic for this post, I’ve learned a couple of things: (1) I don’t know syntax as well as I should, and (2) the behavior of relatives in English, particularly that, is far more complex than most editors or pop grammarians realize. First of all, there’s apparently been a century-long argument over whether that is even a relative pronoun or actually some sort of relativizing conjunction or particle. (Some linguists seem to prefer the latter, but I won’t wade too deep into that debate.) Previous studies have looked at multiple factors to explain the variation in relativizers, including the animacy of the referent, the distance between the pronoun and its referent, the semantic role of the relative clause, and the syntactic role of the referent.
It’s often noted that that can’t follow a preposition and that it doesn’t have a genitive form of its own (it must use either whose or of which), but no usage guide I’ve seen ever makes mention of the fact that this pattern follows the accessibility hierarchy. That is, in a cross-linguistic analysis, linguists have found an order to the way in which relative clauses are formed. Some languages can only relativize subjects, others can do subjects and verbal objects, yet others can do subjects, verbal objects, and oblique objects (like the objects of prepositions), and so on. For any allowable position on the hierarchy, all positions to the left are also allowable. The hierarchy goes something like this:
subject ≥ direct object ≥ indirect object ≥ object of stranded preposition ≥ object of fronted preposition ≥ possessor noun phrase ≥ object of comparative particle
What is interesting is that that and the wh- relatives, who and which, occupy overlapping but different portions of the hierarchy. Who and which can relativize anything from subjects to possessors and possibly objects of comparative particles, though whose as the genitive form of which seems a little odd to some, and both sound odd if not outright ungrammatical with comparatives, as in The man than who I’m taller. But that can’t relativize objects of fronted prepositions or anything further down the scale.
Strangely, though, there are things that that can do that who and which can’t. That can sometimes function as a sort of relative adverb, equivalent to the relative adverbs why, where, or when or to which with a preposition. That is, you can say The day that we met, The day when we met, or The day on which we met, but not The day which we met. And which can relativize whole clauses (though some sticklers consider this ungrammatical), while that cannot, as in This author uses restrictive “which,” which bothers me a lot.
So what explains the differences between that and which or who? Well, as I mentioned above, some linguists consider that not a pronoun but a complementizer or conjunction (perhaps a highly pronominal one), making it more akin to the complementizer that, as in He said that relativizers were confusing. And some linguists have also proposed different syntactic structures for restrictive and nonrestrictive clauses, which could account for the limitation of that to restrictive clauses. If that is not a true pronoun but a complementizer, then that could account for its strange distribution. It can’t appear in nonrestrictive clauses, because they require a full pronoun like which or who, and it can’t appear after prepositions, because those constructions similarly require a pronoun. But it can function as a relative adverb, which a regular relative pronoun can’t do.
As I argued in my previous post, it seems that which and that do not occupy separate parts of a single paradigm but are part of two different paradigms that overlap. The differences between them can be characterized in a few different ways, but for some reason, grammarians have seized on the restrictive/nonrestrictive distinction and have written off the rest as idiosyncratic exceptions to the rule or as common errors (when they’ve addressed those points at all).
The proposal to disallow which in restrictive relative clauses, except in the cases where that is ungrammatical—sometimes called Fowler’s rule, though that’s not entirely accurate—is based on the rather trivial observation that all thats are restrictive and that all nonrestrictives are which. It then assumes that the converse is true (or should be) and tries to force all restrictives to be that and all whiches to be nonrestrictive (except for all those pesky exceptions, of course).
Garner calls Fowler’s rule “nothing short of brilliant,” but I must disagree. It’s based on a rather facile analysis followed by some terrible logical leaps. And insisting on following a rule based on bad linguistic analysis is not only not helpful to the reader, it’s a waste of editors’ time. As my last post shows, editors have obviously worked very hard to put the rule into practice, but this is not evidence of its utility, let alone its brilliance. But a linguistic analysis that could account for all of the various differences between the two systems of relativization in English? Now that just might be brilliant.
Herbert F. W. Stahlke, “Which That,” Language 52, no. 3 (Sept. 1976): 584–610
Johan Van Der Auwera, “Relative That: A Centennial Dispute,” Journal of Lingusitics 21, no. 1 (March 1985): 149–79
Gregory R. Guy and Robert Bayley, “On the Choice of Relative Pronouns in English,” American Speech 70, no. 2 (Summer 1995): 148–62
Nigel Fabb, “The Difference between English Restrictive and Nonrestrictive Relative Clauses,” Journal of Linguistics 26, no. 1 (March 1990): 57–77
Robert D. Borsley, “More on the Difference between English Restrictive and Nonrestrictive Relative Clauses,” Journal of Linguistics 28, no. 1 (March 1992), 139–48
-  Garner’s Modern American Usage, 3rd ed., s.v. “that. A. And which.” ↩