who's to say?

who's to say?

1. No one really knows (to truth about or answer to something). A: "What does the future hold, now that you've left the music industry?" B: "Who's to say, really? I've always been interested in writing a novel, so I may pursue that." A: "Why on earth have they decided to go this route with the new software?" B: "Who's to say what convoluted analytics they employ to come up with their new designs?"
2. According to whose authority? Who's to say I can't take another holiday already? I have the days to take, and it doesn't conflict with anyone else in the office. I know we've had a tough season so far, but who's to say we can't go all the way and win the championship?

who’s to ˈsay (...)?

(spoken) used to say that something might happen or might have happened in a particular way, because nobody really knows: Who’s to say we wouldn’t have succeeded if we’d had more time?