However, it isn't unthinkable that these functions could be performed by a machine, even though there is no telling whether robots will ever replace jockeys.

WSJ: Kentucky Derby: Do Horse Races Really Need Jockeys?

"I find it unthinkable that Nissan won't be at 10% of the market, " he said.

WSJ: Nissan Plans to Pass Honda in U.S.

"I won't stand against Francois Hollande, it's unthinkable, " she laughed.

BBC: Profile: Segolene Royal

In crude terms, it would mean that a bank would have to suffer a 4% fall in the value of all its loans and investments to be wiped out - which hasn't happened that often in history, but is not unthinkable.

BBC: Osborne and the safe size for British banks

So the once unthinkable cuts are now real, and the public isn't predicting the end of the world.

CNN: Obama woos GOP, finally

During the debate he said he didn't want more troops in Iraq, but he was caught on video saying it was unthinkable not to leave 20, 000 troops in Iraq, troops that would still be there today.

WHITEHOUSE: The White House

Even if Dell wanted to retire as king of the PC business--an idea as unthinkable as Mick Jagger's giving up tight pants--his inflated stock price won't let him.

FORBES: Pulled in a New Direction