Our task for today is to understand how we punctuate relative clauses. In the simplest terms, a relative clause is a clause that begins with a relative pronoun (which, that, who, whom, whose). Let’s begin by looking at this example of a sentence with a relative clause:
CNCP patients, whose complaints of pain are not adequately addressed, start to display aberrant drug-related behaviours that are mistaken for addiction.
This sentence—taken directly from student writing—is not incorrect as written, but it doesn’t say what the author intended. Here is what the author meant to say:
CNCP patients whose complaints of pain are not adequately addressed start to display aberrant drug-related behaviours that are mistaken for addiction.
The difference? The second version of the sentence shows that it is about a subgroup of CNCP patients ‘whose complaints of pain are not adequately addressed’. There are many CNCP patients in the world and only some of them suffer in this manner. The first version says that all CNCP patients have complaints of pain that are not adequately addressed. Because of the commas, we have to read the relative clause as supplementary information about all CNCP patients. Technically, our first sentence could be reworded as follows:
CNCP patients [all of them] have complaints of pain that are not adequately addressed. CNCP patients start to display aberrant drug-related behaviours that are mistaken for addiction.
Rewording the sentence in this way reflects the fact that the original sentence portrayed the relative clause as supplementary. But the author’s intention was not to provide extra information about this group of patients; instead, the author wanted to define a particular group of patients under discussion. The lack of commas in our revised version indicate that the information following the relative pronoun is integral to the antecedent noun:
CNCP patients whose complaints of pain are not adequately addressed start to display aberrant drug-related behaviours that are mistaken for addiction.
The bolding emphasizes the integration of the relative clause. This integration is conveyed to the reader by the absence of commas. When we do use commas, we are telling the reader that we are providing supplementary information.
I chose this example because it is easy to see—even without being familiar with the subject matter—that the punctuation in the original sentence was probably misleading. One of the great difficulties in explaining how to punctuate relative clauses is that context matters. I always tell students to take whatever I have said about punctuating relative clauses home with them: only in applying those principles to their own sentences—sentences that they themselves fully grasp—will they come to understand whether a relative clause is integral or supplementary.
If you are familiar with this topic, you will notice that I am not using the traditional terminology (restrictive and nonrestrictive) or the usual variants (defining and non-defining, essential and inessential, identifying and non-identifying). It is possible, of course, to explain what is meant by these terms, but I have never found the common terminology to be particularly intuitive. More recently, I have noticed people using the terms integral relative clause and supplementary relative clause. I find these terms to be more intuitive, which is why I have started to use them in my classroom teaching. I would be interested to know if anyone has thoughts about whether this different terminology is helpful or just confusing.
Now let’s look at some more examples to reinforce the distinction between integral and supplementary relative clauses.
There are many narratives that can be used to illuminate the psychological concept of extraversion.
The relative clause is integral to the meaning of ‘narratives’. The sentence isn’t just telling us that there are many narratives. It is telling us that there are many narratives that can be used in a particular fashion.
The philosophical approach that is articulated by Rorty will set the tone for the proceedings at the conference.
This sentence is telling us what will set the tone for this conference. And it isn’t just any philosophical approach: it is the philosophical approach that is articulated by Rorty. Again, the relative clause is integral to the meaning of ‘philosophical approach’. Now let’s look at some examples of supplementary relative clauses:
Given the educational conditions in Malawi, which is located in eastern Africa, creative teacher training programs are essential.
Using transactional memory, which requires special hardware or software support, will address the problems associated with using locks.
Theorists argue that gender equity, which is defined here in economic terms, is a crucial component in any attempt to address the global AIDS crisis.
In each of these cases, the antecedent of the relative clauses is completely sufficient without the relative clause. A country is a useful example since it is easy to see that you don’t need any additional information to know what is meant by Malawi. Its location within its continent is obviously supplementary information. Likewise, ‘transactional memory’ is a fully defined term: the fact that it requires special hardware or software support is extra information. Take that information away and the term itself is just as informative. In the third example, even though the supplementary relative clause claims to be defining ‘gender equity’, it is doing so in a supplementary way. The sentence is telling us that gender equity is crucial and it is also clarifying what gender equity means in this context.
Here is a final example, one that gives three different versions of the same sentence:
The articles, which stem from the 1970s and the early 1980s, show Lefort intent on persuading the reading public about the totalitarian nature of the Soviet Union and the countries of the Eastern bloc.
The articles that stem from the 1970s and the early 1980s show Lefort intent on persuading the reading public about the totalitarian nature of the Soviet Union and the countries of the Eastern bloc.
The articles which stem from the 1970s and the early 1980s show Lefort intent on persuading the reading public about the totalitarian nature of the Soviet Union and the countries of the Eastern bloc.
The first two sentences follow the pattern I have been discussing. I chose this example because it shows how easily ambiguity can arise when we’re not clear about the punctuation we need. The first sentence is discussing a group of articles and using its relative clause to give us extra information about when they were written. The second sentence, on the other hand, is using its relative clause to identify a particular subset of articles. The implication of the first sentence is that all the articles were written in the 70s and early 80s. The implication of the second sentence is that there is a broader group of articles (presumably spanning a broader time frame); the author is drawing your attention to a subset of that broader group. Needless to say, it is important for the author to clarify which is meant. In my own experience, the decision about how to punctuate relative clauses often helps me to clarify my own meaning. Similarly, in discussing this issue with students, it often emerges that they aren’t quite sure what they were hoping to convey through their punctuation choices.
But what of the third sentence? Is it the same as the second sentence or is it different? In other words, is it okay to use ‘which’ to introduce an integral relative clause? Yes, it is. But while I would love to leave it at that, I feel I should say something about how I view this issue. The good news is that we have already covered the important part: you must signal your intention to your reader through your use of commas. If the information is integral, skip the commas; if, on the other hand, the information is supplementary, show that with your use of commas. Simple enough. But you do need to choose a relative pronoun and, for many, that decision raises a certain anxiety. When I ask students about their habits in this regard, I get a range of replies (often involving something a high school English teacher once said): guessing and then feeling bad; turn taking (first ‘which’, then ‘that’); using ‘which’ because it is more formal; never thinking about it. For a fairly typical prescriptive discussion, see this post from APA Style. For a more nuanced, historical view, try Stan Carey’s excellent post on this topic (as usual, Carey also provides a very helpful roundup of what others have said about this issue).
Given the general uncertainty this topic engenders, what should we do? My own preference—and that is all it is, a preference—is to use ‘that’ without commas and ‘which’ with commas. The first part of this practice is unexceptionable: nobody uses ‘that’ to introduce supplementary information. It is the second part that causes heartache. Look at this simple table:
| integral | supplementary | |
| that | YES | NO |
| which | ?? | YES |
My preference is to replace those two question marks with a ‘NO’. Not, to repeat, because I think this use of ‘which’ is wrong, but only because I like the clarity and simplicity of reserving ‘which’ and ‘that’ for different uses. I start with the important question—do I need commas or not?—and then use that as the basis for my decision about what relative pronoun to use. I explain this to students in just these terms: once they have sorted out the important issue of how to punctuate, they are free to choose their relative pronouns however they wish. But I do stress that this distinction is often treated in more absolute terms in advice on scientific writing. Whether or not this is true across the board, I do suggest that students preparing scientific papers consider reserving ‘which’ for instances in which they are using commas to convey supplementarity. For me it all comes down to this principle: if our audience might find a particular usage to be ambiguous—even if we know that it is perfectly acceptable—it can make sense to avoid that usage.
There is much more that could be said, but this post is already far longer than a blog post should be! If there is anything that you see as needing further explanation or elaboration, I would love to hear about it in the comments.
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This post is the fourth in a series of posts on comma use. The first post dealt with commas and coordinating conjunctions. The second dealt with non-standard commas and punctuating for length. The third dealt with the importance of knowing when you need a pair of commas.
Explorations of Style 