Can superlatives only be used when comparing more than two items?

Question

I was reading the comments on an opinion piece in the Guardian where someone claimed that "...offering you the smallest half" was an "ungrammatical oxymoron in the first paragraph".

Seeing what other people were saying, one person gave the reason for the phrase to be ungrammatical as:

Smaller is the comparator of two. Smallest is the superlative of more than two. So no, you can't have the superlative of two. It's the smaller piece. Hope this helps.

Is this really the case? In my native language I wouldn't think twice about using superlatives when comparing two items, and I think I could very easily have done so when writing in English as well.

If this is not a grammatical mistake, is there something else wrong with the phrase? I realise that going to the comment section to learn about proper English is fraught with peril, but it seems that quite a few people agreed with the comment.

Answer 1

There are two points buried in the item you reproduce from Styggron. I agree with one of them: if you have divided something into two halves, then by definition they both are equal. If they are unequal, then they aren't halves. But honestly, who can be that exact when dividing a piece of pie? However, I think this point accounts for his use of the word oxymoron.

As for the ungrammatical point, I do not agree: it's very common in English to use a superlative even when there are only two things. So referring to the smallest of two pieces is not ungrammatical. It would be equally acceptable to refer to the smaller of two pieces.

Answer 2

Although it's not uncommon to hear people using superlatives to compare two things, many people like me consider it bad grammar and it makes us wince, so you should avoid it. Nobody will think you've made a mistake if you use the comparative.

From this Google Ngrams graph, you can see that "the smaller half" is overwhelmingly preferred over "the smallest half", and the difference is increasing.