Writing Tip 34: That vs. Which
Yes, there really is a difference here, though most people aren’t aware of it. And it’s more than just the insertion of a comma.
The difference between using an adjective clause that starts with “that” and one that starts with “which” depends on whether it is a restrictive clause or not. I’m sure I don’t need to go any further, but just in case I do, think of a restrictive clause as one that is essential to the meaning of the sentence. For example, “Frogs that sing and dance are talented.” If you take out “that sing and dance,” you still have a complete sentence, but a sentence that lost its original meaning. The writer in this instance is talking specifically about ‘frogs that sing and dance’ as being talented, not all frogs.
Non-restrictive clauses do not contribute to the greater meaning of the sentence. For example, “Frogs, which are amphibians, start their lives as tadpoles.” See how the “which are amphibians” clause could be removed and nothing would be lost? It adds information but isn’t essential to the total sentence.
So in conclusion here, with a restrictive clause, use “that.” With a non-restrictive clause, use “which.” Make sense?
Furthermore, did you know that Warner Brothers’ singing and dancing frog is named Michigan J. Frog? I did not. There you go.
If you have any more “that” or “which” questions, let me know!