That Which Doesn't Kill Us...

Many writers—even good writers—do not understand the difference between “that” and which.”  While generalizations are often dangerous, they are helpful in understanding when it is appropriate to use “that” rather than “which.”

Generally, “that” should be used before essential clauses and “which” should be used before nonessential clauses. 

Essential clauses, sometimes called restrictive clauses, are necessary in that the meaning of the sentence is dependent on the presence of the clause.  If the meaning of a sentence would change if the clause were removed, the clause is essential.   Conversely, nonessential clauses can be removed from a sentence without changing the meaning of the sentence.  Nonessential clauses generally provide additional, descriptive information. 

Essential clauses generally are not surrounded by commas. 

Nonessential clauses generally are surrounded by commas.

For example:

Laws that are facially discriminatory are subject to strict scrutiny. 

“That are facially discriminatory” is an essential clause.  The sentence would not be true if the clause were removed because all laws are not subject to strict scrutiny.  Thus, “that” is the appropriate word.

Trials, which are costly, are rarer today than in years past.

“Which are costly” is a non-essential clause.  While the clause does help explain to the reader why cases are tried less frequently today than in the past, the clause is not essential.  If the clause were removed, the sentence would still make sense and be accurate.  

Insurers should avoid writing policies that are ambiguous.

Again, the clause “that are ambiguous” is essential.  Insurers should not avoid writing all policies, only those that are ambiguous.

The exterior of the Smith County courthouse, which was built in 1910, is beautiful.

“Which was built in 1910” is a non-essential clause.  The sentence is accurate when the clause is removed.  “Which,” therefore, is appropriate. 

This rule is not fool-proof, but it will provide you with the right answer the majority of the time.

I’m going to leave out all punctuation from the sentences below to avoid giving away the answers.  See if you can figure out whether “that” or “which” is appropriate.  I’ll post the correct answers next time.

No one should trust companies that/which break laws.

Some people believe jails that/which are often overcrowded breed criminals.

Appeals that/which are granted before final disposition are interlocutory.

Firms that/which offer bonuses are desirable places to work.      

United States District Courts that/which cannot hear all cases are courts of limited jurisdiction.

Trials that/which involve numerous parties take longer than two-party trials.