How to deal with your relatives (i)

Of course, the relatives I’m talking about here are relative clauses.

OK, don’t panic; let’s take this step by step.  First of all, a clause is a sort of mini-sentence that is part of a bigger sentence.  Here’s an example:

   I telephoned the fire brigade   while you were watching TV

Essentially, a clause is a group of words with a verb and its subject: that is, the thing (or person) that ‘does’ the verb.  The verbs in my example are telephoned and were watching, and the subjects who ‘did’ them are I and you, respectively.

These two clauses are not equal, however.  If I were to enter a room and announce in a loud, commanding voice, “I telephoned the fire brigade,” it would certainly cause a stir but it would be a perfectly comprehensible thing to say.  If, on the other hand, I burst into the room crying, “While you were watching TV,” it would be odd.

“Yes?” you would ask.  “What happened while I was watching TV, tell me!”

Because, you see, some clauses are main ones, like I telephoned the fire brigade, and others are dependent; that is, they depend on the main clause to make sense, in this case, telling you when I did the telephoning.

   I telephoned the fire brigade   while you were watching TV

          (main clause)                         (dependent clause)

So far, so good.  So what is a relative clause?  Well, it’s a dependent clause in which the subject ‘doing’ the verb is a word like which or who or that.  These are words that substitute for words in the main clause.  Here’s a couple of examples:

   The clock that stood in the hallway struck the midnight hour.

   The slippers, which Cinderella had been wearing all evening, were beginning to cause blisters.

In the first sentence, the word that stands in for the word clock in the main clause (The clock . . . struck the midnight hour), while in the second, which replaces slippers (The slippers . . . were beginning to cause blisters). This has the wonderful effect of avoiding unwanted repetition.

Now, these relative clauses are sitting inside other (non-relative) clauses, just like real relatives who sit inside your house and expect cups of tea.  Sometimes, though, they hang around at the end:

   The prince stumbled upon a glass slipper which had fallen from Cinderella’s foot.

You will notice that in each case the word which (or that) comes immediately after the word it refers to: clock, slippers or slipper.  These words are called relative pronouns because they relate to the previous noun.

Anyway, back to my point.  The received wisdom is that these clauses fall into two types: defining clauses (also known as restricting or limiting clauses) and non-defining clauses.  The former have no commas whereas the latter are marked off by commas.

   The car that is parked outside my house is a beat-up Ford Cortina  (defining)

   The car, which is parked outside my house, is a beat-up Ford Cortina  (non-defining)

What is the essential difference between these two types?  The grammar books are all in firm agreement:

“Defining clauses provide information which cannot be left out, as it identifies what is being referred to. . . Non-defining clauses provide additional information, which can be left out.”          (McCarter, S. Ready for IELTS, Macmillan, 2010)

And here is another grammar book:

“The best way to understand the difference . . . is that the former [defining] cannot be removed from a sentence without messing up the main point of that sentence [while a non-defining clause] can be lifted right out of that sentence without muddying the main point.”                        (Casagrande, J. Mortal Syntax, Penguin Books, 2008)

They mean well, these grammarians, yet generations of students have had apoplexy trying to work out what constitutes a “main point” and whether it can be left out without “muddying” anything.  They also wondered why the clock and the glass slipper needed to be identified in the first place.  How many chiming clocks were there in the king’s palace, anyway?  Who else was wearing glass slippers that night?  Shouldn’t the prince be told?

Yet they could have saved themselves the effort, because the real difference between defining and non-defining clauses is actually much simpler than that.  It is this: non-defining clauses have commas and defining ones don’t. That’s it.  It’s that simple.  Everything else is pure make-believe.

Let’s see what happens when you put commas into things.  Take a simple sentence such as,

   The clothes which I bought in the charity shop are very fashionable.

If you said this aloud you’d probably say the underlined part in one single ‘chunk’, and it would constitute a single idea, or ‘thought’.  Put the commas in, however:

   The clothes, which I bought in the charity shop, are very fashionable

and the idea becomes broken into two (and your voice will drop after “clothes” when you say it) and so there are now two ‘thoughts’.  This will give the second part (the bit that begins with which) the effect of adding extra information about the first part (the clothes).  Take those commas away again and we are back with one single ‘thought’, the clothes which I bought in the charity shop, as if it were all just one idea.  So the difference between the two types of relative clause is purely a matter of punctuation, and has nothing whatever to do with grammar.  Contrary to what the grammar books will tell you, it isn’t that a non-defining clause must be written with commas, but that putting in commas is what makes it a non-defining clause.