For most people “that” and “which” can be used interchangeably, it doesn’t really matter, the sentence feels good to the author either way. In fiction this is probably correct, but in technical writing it can be really bad news. Million dollar lawsuits have been held over a misplaced comma, that, or which.
This is because they actually are different.
No, seriously, they are. Keep reading.
“That” is used (when used correctly) for a restrictive clause, and “which” for a non-restrictive clause. Put another way, “that” limits what we’re talking about, whereas “which” adds information.
Ah, so now you can see why contracts and technical papers need to get it right, and it doesn’t hurt authors to understand it as well.
Three of the cups that have blue flowers belong to me.
“That” limits the cups we’re talking about. Only the ones with blue flowers belong to me.
If I said:
Three of the cups, which have blue flowers, belong to me.
“which” tells you more about the cups. All these cups have blue flowers on them.
We also surround the clause telling us more information with commas.
And that is where your million dollar court case is born. When someone sticks commas in a sentence with “that” which should be restrictive, and now people want to think it is non-restrictive.
Three of the cups, that have blue flowers, belong to me. Adding the commas makes it both wrong and confusing.
If you haven’t understood a word I’ve said, that’s fine. Write fiction, not contracts or technical papers.
If you have understood this blog, congratulations!
Helen is available to line edit and/ or content edit fiction and non-fiction. Rates on application.