The Globe and Mail today had a discussion by Russell Smith about the use of “that” and “which.” Neither my husband (a teacher of English for 34 years) nor I were aware of the distinction, though I think we may have known it subconsciously. “That” is used for a restrictive clause, “which” for a non-restrictive clause. Bill got out Wilson Follett’s Modern American Usage and read me a long discussion of the situation. Follett (following Fowler) says that keeping the difference between the two words means that you are not relying just on commas to make the distinction between non-restrictive (which Smith calls non-essential) and restrictive (essential) clauses. The short story writer Dorothy Canfield Fisher in discussing her method of revising said she goes through a story “cutting out the whiches.” “Which” is an inelegant word, it seems to me, but I don’t know why. You can sometimes convert the which clause to a participial phrase, which seems more elegant, or to some other construction. For example, I could revise the previous sentence to “…a more elegant participial phrase”, cutting out the whiches. I am using elegant and inelegant under the influence of Russell Smith’s column.
When I say Bill and I might have known the distinction subconsciously, I am thinking of when I read aloud to myself what I have written (as I always do before sending it off for publication) and discover that a certain word or phrase doesn’t sound right.
As the old saying goes, you learn something new every day, which only makes you realize how much you don’t know and how little time you have left to know everything.