"Which" and "that"

[Bethany K. Dumas]

I did not always pay attention to the rule until I got into law school.
I suspect that court cases are sometimes decided based upon the rule, but
a sane approach is that is the U of Del ELI Grammar Hotline:

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Q. Which of the following uses is correct (and why)? The sentence comes
from a limitations statement from a warranty document. Sometimes I think
legal writers use words incorrectly because the correct word sound too
common.

The owner may also have other rights which vary from state to state.
The owner may also have other rights that vary from state to state.

A. They are both correct. You can use either that or which in restrictive
relative clauses that refer to inanimate nouns. The clause "which (that)
vary from state to state" is a restrictive clause because the information
in the clause is essential to the understanding of rights.

If the relative clause, though, is non-restrictive, only "which" can be
used as the relative pronoun. The relative clause in the following
sentence is non-restrictive because the information in the clause is not
needed to identify the Lincoln Memorial. Using "that" in sentence 2 is not
possible.

The Lincoln Memorial, which is located in Washington D.C., attracts
millions of visitors each year.
*The Lincoln Memorial, that is located in Washington D.C., attracts
millions of visitors each year.

See http://www.udel.edu/eli/questions/g11.html.

Bethany