Parenthetical Elements: Use a Complete Set of Commas or Dashes to Enclose an Interrupter
by Tina Blue
July 8, 2005
An interrupter, or parenthetical element, is any sentence element that interrupts the forward movement of a clause. An interrupter is set off from the clause it interrupts by parenthetical punctuation.
Parenthetical elements vary in intensity, and their relative strength is indicated by the form of punctuation used to set them off. Sometimes, a weak parenthetical element needs no punctuation at all:
~I also doubt his story.
The main forms of parenthetical punctuation are, in ascending order of strength, commas, dashes, and parentheses. (Square brackets also have special uses as parenthetical punctuation.)
EXAMPLES:
Commas
~Take, for example, the way Linda responded to being accused of bias.~That explanation, as I have already said, doesn't really hold water.~You should, nevertheless, continue your efforts despite this recent disappointment.~He cannot, however, hope to defeat a popular incumbent.Dashes
~There is no way--and no particular reason--to gauge popular interest in such an approach.~The mythographer Joseph Campbell--who visited this campus in the 1980s, by the way--is perhaps best known for his book The Hero with a Thousand Faces.Parentheses
~The last person who leaves (that is, if anyone ever manages to get out of here at all) needs to make sure all the lights are out and the furniture is put back in its proper place.~The War of the Worlds (this isn't the first time it has been made into a movie, you know) is based on a well-known science fiction novel. Commas and dashes differ from parentheses in that they can be used singly, whereas parentheses always occur in a complete set. Some of the examples above have parenthetical elements embedded within the parenthetical elements. In those examples, the internal interrupters are set off by a single comma:
~The mythographer Joseph Campbell--who visited this campus in the 1980s, by the way--is perhaps best known for his book The Hero with a Thousand Faces.~The last person who leaves (that is, if anyone ever manages to get out of here at all) needs to make sure all the lights are out and the furniture is put back in its proper place.~The War of the Worlds (this isn't the first time it has been made into a movie, you know) is based on a well-known science fiction novel. But notice that in each case, the element set off by a single comma ends the structural unit, like this. The original structure is not picked up following the parenthetical element.
Similarly, an element set off by a single dash can end a sentence--as this aside does right now. But once you have set that element off by either a comma or a dash, you cannot go back to the clause you have interrupted, unless you use another comma or dash to complete the set of parenthetical punctuation.
WRONG:
~But notice that in each case, the element set off by a single comma ends the structural unit, like this and you can't go back to pick up the original clause without using the second half of the set of parenthetical punctuation.~Similarly, an element set off by a single dash can end a sentence--as this aside does right now, but you can't go back to pick up the original clause without using the second half of the set of parenthetical punctuation.CORRECTED (by completing the set of parenthetical punctuation):
~But notice that in each case, the element set off by a single comma ends the structural unit, like this, and you can't go back to pick up the original clause without using the second half of the set of parenthetical punctuation.
~Similarly, an element set off by a single dash can end a sentence--as this aside does right now--but you can't go back to pick up the original clause without using the second half of the set of parenthetical punctuation. *If an interrupter set off by either commas or dashes occurs within a clause rather than at the end of it, then that interrupter must be set off by a complete set of parenthetical punctuation.*
That parenthetical element is not an integral part of the clause or phrase it is interrupting. It is being stuck into it from the outside. Consider the parenthetical punctuation to be a part of the element it is enclosing. Imagine those commas or dashes to be cute little handles. When you put the interrupting element into the clause, lower it in with BOTH handles. If you decide to remove the parenthetical element, take it out with BOTH handles, and don't carelessly leave one handle behind.
Make that picture in your head. You've got a little basket with handles, and your interrupting element is in the basket. Lower the element into the sentence with BOTH handles. If you use only one handle, the basket will tip, and the words will spill all over your main idea, making a scrambled mess of it.
*Remember, if the interrupter occurs within a clause, leaving out one of the commas or one of the dashes is just as wrong as it would be to leave out one half of a set of parentheses.*
