Revisiting the 'unknowns' - known and unknown alike

IN 2002, then-US Secretary of Defence Donald Rumsfeld was asked about the lack of evidence linking the Iraqi government with the supply of weapons of mass destruction to terrorist groups.

He said: "There are things we know we know. We also know there are known unknowns; that is to say, we know there are some things we do not know. But there are also unknown unknowns - the ones we don't know we don't know. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones."

Within a week, the world will know the outcome of one of the most closely-watched elections in recent history, but as it stands now, it is anyone's guess. Opinion polls place Democrat Joe Biden in the lead, but sceptics point to the 2016 elections, when the polls had Hillary Clinton as the clear frontrunner - only to be proven spectacularly wrong. Applying Mr Rumsfeld's quote, the US election would qualify as a "known unknown" - possibly the biggest in the near term.