Martin Schulz, the newly-reappointed president of the European Parliament, is a known unknown.
Lord Hill of Whatsit, who is heading the British list of one candidate to become an EU Commissioner, is an unknown unknown.
It is extremely well-known in polite society that a known unknown never has a go at an unknown unknown in public, at least not knowingly and certainly not without knowing what he or she is talking about.
And Martin Schulz should have known better than to knowingly lash out at poor Lord Hill of Whatsit, accusing him of being - and here I paraphrase, - "ein bounder und ein cad."
Mr Schulz, who seemed to know an awful lot about this unknown unknown, accused Lord Hill of Whatsit of being a raving loony eurosceptic, but only on the days when he, Lord Hill, had any thoughts in his head which he, Mr Schulz, didn't think was very often, what with Lord Hill being an evil secret agent intent on toppling the EU institutions from the inside.
Furthermore, opined Mr Schulz, Lord Haw-Haw of Whatsit would become a Commissioner over his, Mr Schulz's, dead body.
Mr Schulz's remarks were, of course, a gift to Nigel Farage, recently promoted from a known unknown to a known known and therefore perfectly entitled to upbraid a mere known unknown such as old Schulzy.
Mr Farage, who runs a very successful import/export business dealing in all forms of euroscepticism, accused Mr Schulz of interfering in British affairs and politically prejudicing Lord Hill's nomination from the allegedly politically-neutral post of EP President (by appointment).
This attack triggered a public response from Mr Schulz which amounted to an unapologetic unapology, when the very least that had been expected was an apologetic unapology or, better still, an apologetic apology.
Mr Schulz grudgingly observed that he had been told by friends (of Lord Hill's or Mr Schulz's was not clear), that the good Lord was, in fact "rather pro-European for the UK context" and that the British candidate would be judged, along with all the other candidates for Commissionerships, not on his politics but on his perceived abilities - although he added that politics would obviously come into it, what with the European Parliament being a parliament.
Meanwhile, what Mr Schulz was doing to destroy the reputation of European diplomacy, the equally-newly appointed President of the European Commission, Jean-Claude Junker, was doing to destroy the reputation of the "high five", a gesture originating in basketball and traditionally conducted between victorious players on the same team.
In a novel twist, Mr Juncker, who emerged recently as a surprisingly known known, deployed the "high five" in tandem with a losing player on an opposing team. This of course was Prime Minister David Cameron, an extremely known known who more than adequately blocked what could easily have been mistaken for an aggressive Junckerian manoeuvre
One British newspaper report described the "Yo, bro" moment, (captured as luck would have it by a passing European Commission photographer), as "an apparent sign that Mr Juncker harbours no grudge over the prime minister's failed attempt to block Lord Hill's appointment."
This was an error: the report should have read that the high five was "a clear sign that Mr Juncker is determined to hide his boiling fury over the prime minister's successful attempt to paint Mr Juncker as a chain-smoking-oh-go-on-then-just-a-quick-one-federalist-has-been "
So, what fate awaits Lord Jonathan Hopkin Hill of Whatsit? Earlier this week I wrote to Mr Google to seek some details and by return of post I was informed that Lord Hill was an ace public relations man, spin-doctor and all-round smooth political operator, all skills Martin Schulz should welcome if he cares about the EU's future. (These qualities also make Lord Hill the ideal chap to suggest a high-fiving photo opportunity between enemies to symbolise friendship...).
When asked by a continental colleague what I thought of the cove, (being a fellow Brit I would of course know everything about him) I responded that, in my opinion, Lord Hill of Wherever was a fine sort of chap with a jolly good head of hair, although a little indecisive at times.
This is based on careful study of a photo in a newspaper and the fact that Lord Hill had emphatically denied being interested in moving to Brussels from what he calls "the British Isles".
Since then his Lordship is on record as saying that, having thought a bit more about it, becoming an EU Commissioner is a fantastic opportunity and "I would be mad not to do it".
The opposite is also true: if he does get the job, which brings with it the status of known unknown, madness, although not compulsory, will be a positive asset.