That, which, who

The use of the correct relative pronoun is one that used to be extremely important – if you wanted to speak and write correct English – but it has tended to excite less wrath from the pedants, if used incorrectly, in recent years. 

We are talking here about “that”, “which” and “who/whom”. In general terms, “that” should be used to refer to persons, animals and things, “which” to animals and things, and “who/whom” to persons. 

The basic rule is that “that” should be used to define the meaning or intention of the preceding word or phrase, as in “the book that I put on the shelf was a novel by Dickens”, whereas “which” would be used when the identifying information has already been supplied, as in “The novel by Dickens, which I put on the shelf, was far too long for me.” 

The use of “which” implies that you are referring to a specific item as opposed to another one, but this is not universal – “that” is often used in such a context. 

You can use “that” for persons when any member of a defined group is being referred to, and “who” when it is a particular person. Examples here might be: “People that live in glass houses shouldn’t throw stones” and “Bert, who lives in a glass house, threw a stone.” In British English, it is common to use “who” in preference to “that” when there is uncertainty, but Americans tend to prefer “that”. 

It has to be said that the use of these relative pronouns is dying out in some quarters, and if omitting one does not change the meaning of a sentence, then there is nothing wrong in doing so. However, there are occasions when confusion can be avoided by including one. 

Consider this example: “Mr Jones said yesterday some shares fell rapidly”. This could mean either that he said this yesterday or that the shares fell yesterday. The ambiguity can be avoided very easily by placing “that” either before or after “yesterday”. 

In the interest of not using more words than necessary to make one’s meaning clear, omitting that/which/who should be encouraged – but only when the meaning really is clear. 

As to using “that” or “which”, it depends on how precise you want to be. A general principle of modern grammar should be that a difference that makes no difference is not a difference worth too much bother!

© John Welford