different than

As far as I know, no one has yet promoted distinct than or apart than; why, then, different than? Follett notes that this construction is commonly defended with two arguments:

  1. Other, which is logically equivalent to different, is idiomatically followed by than.
  2. Insistence on different from sometimes leads to wordiness.
He comments as follows:
Both arguments have merit. But the first does not dispose of the educated American's strong feeling that different from is idiomatic and hence inviolable; and the second does not dispose of the writer's implicit obligation to find alternative ways of expressing thoughts that work out awkwardly in the forms that first occur to him.
Follett's reaction to the first argument is echoed by Simon:
Grammar and syntax are partly logical ... but they are also partly arbitrary, conventional, irrational. ... logic would have to strain desperately to explain the exclusive correctness of different from, given the exclusive correctness of other than, which would seem to justify different than, jarring though that is to the cultivated ear.

Unfortunately, we who subscribe to this view cannot realistically hope to persuade anyone with such an argument except those whom we already judge to be "educated" or "cultivated". Our position is strengthened, however, by the observation that there is etymological justification for each legitimate exception to the rule that the subordinating conjunction than is used only after comparative modifiers. For example, rather is derived from the Old English hrathor, the comparative form of hrathe, meaning rapidly. Indeed, Webster's 3rd reports that this meaning is retained today in some British dialect. The origin of other is somewhat more obscure, but Skeat traces it to the Indo-European anteros, which is derived from the adverb an, meaning on the other side, and the comparative suffix teros. He comments as follows:

Thus the original sense is more than that, or beyond that, used in pointing out something more remote than that which was first contemplated; hence its use in the sense of second.

However, the second argument mentioned by Follett is the more popular of the two. The American Heritage Dictionary, for example, observes that The campus is different than it was 20 years ago is preferable to The campus is different from how it was 20 years ago. Moreover, it claims, there is a subtle distinction in meaning between the two constructions:

How different this seems from Paris suggests that the object of comparison is the city of Paris itself, whereas How different this seems than Paris suggests that the object of comparison is something like the way things were in Paris or what happened in Paris.
Bullshit. In any case, the basis for this argument seems to be that the construction different from is not suitable in all contexts in which a difference is to be noted. It appears that different is distinguished here from distinct, apart, etc., not on any grammatical or logical grounds, but rather by the perception of a need. On this point, Follett continues:
There is always some acceptable way of saying what is meant, and it is often better to find a way around a linguistic thicket than to bull one's way through it. To condone different than because it is sometimes awkward to follow different with the accepted preposition is defeatism.
Fowler, unfortunately, provides no specific advice on this issue. He does offer a discussion of the relative merits of different from and different to—an irrelevant controversy from the American perspective—but apparently, he either had not been exposed to the barbarism at hand or did not attribute it to his targeted audience of "semi-educated" readers. However, Follett's position is reminiscent of Fowler's general advice concerning "clumsy patching":
When a writer detects a fault in what he has written or thought of writing, his best course is to recast the whole sentence. The next best is to leave it alone. The worst is to patch it in such a way that the reader has his attention drawn, works out the original version, and condemns his author for carelessness aggravated by too low an estimate of his own intelligence.
Thus, once we agree that The campus is different from how it was 20 years ago is too wordy, rather than to patch it sloppily as The campus is different than it was 20 years ago, we might recast the whole sentence as The campus has changed over the past twenty years