Here's a little riddle for you: which left-wing extremist said this: "Bin Laden should be put on trial... because a trial would be the profoundest and most eloquent statement of the difference between our values and his."
And who said this: "[There was] no attempt whatsoever that I can see to arrest [Bin Laden] and put him on trial ... This was an assassination attempt, and is yet another tragedy, upon a tragedy, upon a tragedy."
Was it (a) the man lauded by David Cameron because "he's served this country, he's served this party", or (b) the one lambasted for his "security-threatening, terrorist-sympathising, Britain-hating ideology"?
You've guessed, haven't you? The first quote comes from the prime minister's fellow old Etonian and wannabe successor Boris Johnson, and the second from Jeremy Corbyn. And yet although both were saying pretty much exactly the same thing, Mr Cameron regards one as a valued colleague (or so he would have us believe) and the other as someone to be cast into oblivion as a terrorist sympathiser.
Which just goes to show, yet again, that what is said by party leaders on conference platforms should never, ever be taken at face value. Even so, the gulf that separated what Mr Cameron said on Wednesday and what his government is actually doing was so vast that it had me reaching for my dictionary.
The phrase that came to mind as I listened to him was "cognitive dissonance". Definition: "the mental stress or discomfort experienced by an individual who holds two or more contradictory beliefs, ideas, or values at the same time, or is confronted by new information that conflicts with existing beliefs, ideas, or values."
For example: he says the housing crisis is "one big piece of unfinished business" and that he wants more families to be able to own a home of their own. At the same time, he adopts policies that push property prices up to yet more stratospheric levels and deplete yet further the stock of affordable homes.
He also says he intends to tackle Britain's deep social problems: the "scourge of poverty ... the brick wall of blocked opportunity". But he says nothing about his proposed changes to tax credits (the words didn't appear once in his speech, by the way) that, according to the Resolution Foundation, chaired by former Tory minister David Willetts, will together with other planned cuts increase the number of working families living in poverty by 200,000 by 2020.
Yet despite this yawning gap between rhetoric and reality, the prime minister appears to be suffering from no mental stress or discomfort whatsoever. On the contrary: he gives the impression that he's enjoying himself immensely, basking in the warm glow of an unexpected election victory, and that he feels he now has a real chance to create what he called a "greater Britain, made of greater hope, greater chances, greater security."
There can be only one explanation: he knows exactly what he's doing, but thinks we won't notice. He thinks he's so good at the talking that we won't realise in which direction he's walking. He's so excited at the prospect of occupying the political ground that Labour has (temporarily?) vacated that he can see little else. When he looks out of the Downing Street window every morning, he sees a future that is only blue.
But let's borrow another concept from the lexicon of psychology: maybe he's in denial ("a refusal or unwillingness to accept reality"). Because I spotted another word that somehow failed to make a single appearance in his conference speech. It was the dog that didn't bark, the elephant in the room - feel free to choose your own metaphor.
The word was... referendum. As in the EU in-out referendum, which hangs around the prime minister's neck like a lead weight. If Mr Cameron urges a Yes vote - which he will - and the country votes No - which it might - his career will end in chaos and ignominy. It is a prospect so terrible that on Wednesday he could not bring himself even to utter the word.
No wonder he prefers to imagine a wonderful world in which the least well-off miraculously find well-paid jobs and affordable homes and no longer need any help from their fellow tax-payers. It's a world in which ethnic, religious and gender discrimination has vanished and every British Muslim bakes prize-winning cakes.
It's not the real world, of course, nor a world that the rest of us recognise. It's the world of the PR man - which he once was, and still is.