To quote (in full) the former US Defence Secretary Donald Rumsfeld "there are known knowns; 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." It is worth recounting the scale of this insightful gibberish as it feels rather relevant to the current British political predicament.
This is an unusual election in that there is a significant known known - the Conservatives are going to be the next Government, with Theresa May as Prime Minister. We know that, right? But then there are things we thought we 'knew' - like that there was no way the UK public were actually going to vote to leave the European Union. That turned out to be completely wrong.
Received wisdom is a fragile thing these days. This is of course not a UK-specific phenomenon, just look at the fresh-faced President-elect Emmanuel Macron, and the not-so-fresh-faced President Trump.
It is the known unknowns that are driving much of the double-think campaigning that the Conservative Party are currently driving in their messaging. This is because the British voting public have become a little unreliable of late. Therefore they (the Conservatives) are having to play an odd game with us; in that on the one hand they leave the Labour Party to eat itself alive and demonstrate that Jeremy Corbyn is absolutely incapable of being Prime Minister, whilst on the other hand try and convince you that he could be Prime Minister. They need to do this of course, because if you don't believe he could ever be Prime Minister then you might not bother to turnout and vote Conservative, or indeed do something silly like actually vote Labour.
The known unknown of the British public is an important one. Although the polls are significantly in the Conservatives' favour, the electoral arithmetic (thanks to our good old First Past The Post electoral system) is not so straight forward. Take out the less contestable Scotland and Northern Ireland, and this election battle comes down to areas of England and Wales. And with the Liberal Democrats strongly contending pro-remain areas, the pitch that the Tories are playing on is suddenly much smaller, and that enormous poll lead is significantly diluted - every seat really does count.
Now I'm not saying there's going to be a major upset, but I am saying there's still unknowns in play and the Conservatives will be sweating to the last vote is counted.
Then there's Brexit. Another impenetrable bag of known knowns and known unknowns. How do we, in the communications world, advise our clients and companies how to navigate these murky waters? We know what the Prime Minister wants to achieve (Red, White and Blue Brexit, cake and the eating of it, etc., etc.) and we know what the EU wants to achieve (a significant divorce bill). But how these ambitions mash together over the next two years is frankly a known unknown.
What we can tell them is that we know there will be a Conservative Government (though the level of the majority is unclear). So now is the time to get your Brexit priorities clear, and prepare to take them to May's administration. Also, prepare to be flexible. The Article 50 window is going to be a messy, frantic window, nobody is going to get everything they want - but in chaos there's opportunity. Be ready to evolve with the agenda and watch Brexit's developments closely as doors will open and shut quickly amongst the parliamentary clamour.
Of course, there's also the unknown unknowns, which we know we don't know about. So let's not speculate about them - I'll ask David Cameron.