From Longman Dictionary of Contemporary Englishwho can say?who can say? (also who’s to say?)NOT KNOW used to say that nobody can know somethingWho can say what will happen between now and then?Many women believe that skin cream makes their skin look younger, and who’s to say that they’re wrong? →say
Examples from the Corpus
who can say?• It's unlikely that we'll find anything of value there. Still, who can say?• Beyond that, who can say?• But where such storiesoriginated, who can say.• Whether this is ultimately a good or a bad thing, who can say?• Anyone who can say so clearly just what Derrida is saying, or doing, immediately puts the reader in his debt.• We're the only ones who can say that and know it's true.• Once the traffic starts to move, who can say what beauty and what truth such people may not bring us?• And who can say what will be going on by the time you read these words?