You know how some things stick with you, and you never forget them? Well, "different from" is one of those things for me. I had written a paper for one of my college classes, and the paper came back with this written in the margin in red and each instance was underlined three times:
Guess who hasn't written "different than" since then?
I was telling Stacy this the other day, and she disagreed. "Why can't it be different than?" she asked. I told her I thought it was because you use from with the word differs, and different is a derivative of differs. She disagreed again. "Unh unh. They're different words."
Different from what? :-)
So, we bet on it (we never agreed upon the terms, though), and off I went to research the subject. My source? The only source for style: The Elements of Style by William Strunk Jr. and E.B. White. There on page 70 it says,
Different than. Here logic supports established usage: one things differs from another, hence, different from. Or, other than, unlike.
Nope, no mention of different than being an acceptable usage.
What do I win, Stacy? :-)