One time, not so long ago, I used to be a purist about the word "unique," insisting that it had a singular value and therefore could not be modified by any adverb indicating a matter of degree, such as "very." I see that I was not alone. For a few brief, shining moments in my superior grasp of the English language, I even at one point insisted that the word "unique" could not be properly modified at all. (I later relented when I discovered that this was a truly unique misconception.)
Having seen the writings of some other folks who share the disapproval of the term "very unique," I gave it some more thought and decided that, contrary to the protestations of other purists, the word "unique" can properly be modified in a number of ways. My very unique reasoning is this: the word seems to have an absolute meaning requiring a binary value, but does not.
When speaking to matters of degree, there are three states of a an adjective or adverb: positive, comparative, and superlative. Think "good, better, best" for an example; or "excellent, more excellent, most excellent" for another. Purists argue, in effect, that the meaning of the word "unique" precludes it from usage in either the comparative or superlative forms. Nor can it be intensified with "very" or weakened with "somewhat," and so on. Unique, meaning "one of a kind," is either true or false, they say, with no in-between.
But what does it mean to be one of a kind? The way I think of it, there are two ways in which that concept cannot be limited to a binary value, but must account for matters of degree. One of these is breadth or category, while the other is depth or intensity.
Imagine ten cars, all Model-T Fords. In 1911, they are black, just like Henry Ford and God Himself intended. Now imagine that one of those is bright, fire engine red. That car, in the scope of your set of ten, is unique. Now take that red Model-T and propel it into the year 2001, surrounded by Ford Mustangs, Honda Accords, and BMW 750i’s. That Model-T is still unique, but in a very different way. There is no other like it, but in relation to a much larger set. In other words, it is unique not just with respect to nine other cars, but with respect to millions. In 2001, that car is more unique than in 1920.
Hurl that same car forward another fifty years, to 2051, where every car is aerodynamically styled, runs on fuel cells or cold fusion, and comes in colors not yet imagined by the human mind. They are made of materials unheard of in 1920, and unusual even in 2001. The controls and gauges are all different – maybe these cars have altimeters. Their computing power far exceeds anything on a desktop in 2001. Is that Model-T unique in 2051? Ya, sure, you betcha – but look at how. Any observer can find more items of difference than items of similarity. The red Model T in 1921 was different in only one way –its color. This Model T in 2051 is different from all other cars in more ways than we can count. Both are "one of a kind" but one is profoundly more so than the other – and hence, more unique.
The purists will sputter, "but you can’t say that!" True, from a logical, mechanical point of view, both cars are unique, and that’s all – no more, no less. But humans are not computers – we don’t use language mechanically, we use it intuitively. On a purely intuitive level, the red car in 1921 is unique; in 2001, it is more unique, and in 2051, it is most unique. (Or, in the alternative, "very unique.") Because that’s they way we think about language, and the common usage proves that is the case.
And that’s the most unique way I’ve ever heard it argued.
Note: Unique is not a superlative.
Source: nowhere but the dark, twisty passages of my mind.