The vast, terrifying vista of boundless possibility.

The slippery slope argument is a well-known logical fallacy for two reasons. Firstly, it is almost universally wrong. Secondly, it is almost universally believed. This is because human beings are innately loss-averse, preferring the certainty of the here and now (however imperfect) to the unknown possibilities of change.

It is only when the here and now crosses a significant threshold of imperfection that uncertainty begins to look inviting. The mildly discontented compare the known and the unknown and say “don’t rock the boat, it could be worse”. The strongly discontented make the same comparison and say “anything would be better than this”.

This is the fundamental distinction between conservatism and radicalism. It is common in the West to assume that “conservative” is a synonym for “right-wing” but this is not strictly true. Margaret Thatcher fit the description of the classical social conservative but her economic reform programme was profoundly radical, coming from a conviction that the economy was in terminal decline and could only be rescued by extreme measures. During the putsch against Mikhail Gorbachev in 1991, the “conservative” faction consisted of the hard-boiled gerontocrats of the unreformed Communist Party, and the radicals were Yeltsin and his free-market advisers.

So conservatism-with-a-small-c is not a left- or right-wing label, but a resistance to movement, in any direction, away from the established local norm. And a little bit of conservatism is usually good for you, as it discourages hasty change and allows space for due reflection before taking action. But too much conservatism, too acute a fear of the mythical slippery slope, leads inevitably to paralysis.

Unionism (in a UK context at least) is a fundamentally small-c conservative position, in that it is primarily concerned with the risks of change. A mild form of conservatism would seek to manage these risks without ruling out change entirely. But the Northern Irish version often tends towards resisting change at any cost, and this resistance to change is not limited to the constitutional question.

Conservatism, like other broad -isms such as fundamentalism or liberalism, is not a logical position so much as it is an emotional one, a conviction born of temperament rather than intellect. Someone who is conservative on constitutional matters will tend to be conservative in other political areas, because they employ the same emotional vocabulary.

And we can see a broad party-political correlation between constitutional, social and economic conservatism. No matter how much one may argue that gay marriage has nothing to do with national identity, it is still remarkable how strongly aligned the conservative-radical axis is in both matters. This correlation is stronger in party politics, where following the agreed line is expected, than it is in the opinion pages, where free-thinking political catholicism (with a small c) is more acceptable.

The DUP can therefore be understood on one level as a small-c conservative party, one which is quite content (unlike Thatcher) to drink the milk of government subvention, while standing firm against both social reform and constitutional uncertainty. They look out across the vast, terrifying vista of boundless possibility and see only lions and tigers and bears.

And yet they voted for Brexit.

Because the DUP are also a deeply fundamentalist party. Religiously fundamentalist due to their roots in evangelical Protestantism, with its emphasis on returning to a simpler time when the faithful communed directly with God; but also politically fundamentalist, clinging to a concept of Westphalian sovereignty that dates from a simpler time, when a country could do whatever it liked within its own borders.

This “return to a simpler time” trope is key: while religious and political fundamentalisms may style themselves as “more authentic” forms of conservatism, they are not conservative at all. Because to make the world that they desire, they need to unmake the world that exists now. By trying to retreat into a sketchily-remembered past, they are just as radical as those who want to rush headlong into a sketchily-conceived future.

The nostalgic line drawings of Brexit fundamentalism could no better survive harsh reality than the idealistic line drawings of Communism. And yet simplistic ideas are seductive precisely because of their simplicity. The modern world is complex, baffling, exhausting. Simplicity is bliss.

And so the DUP, like their big-C Conservative allies, find themselves torn between their small-c conservative and radical wings – and in both cases the conservative factions are the pragmatic centrists, while the radical factions are the fundamentalist Brexiteers.

The triumph of the radicals may also help to explain their sudden onset of incompetence. Because when one is defending a strongly conservative position, all one needs to do is obstruct. The DUP’s infamous immovability is highly adapted to slow down processes, drag out negotiations and force the opposition to exhaust themselves into submission.

But this tactic does not work when one’s position is radically fundamentalist. Brexit is about action and change, and it is the EU’s institutional apparatus that is the conservative boulder in the road. Europe is standing still and the UK is the one squabbling itself into submission.

The DUP can’t stonewall Michel Barnier, because he is the conservative now, and the DUP are the radicals. They are the ones who took the leap into the brave unknown. And they’re still struggling to understand what just happened.

Andrew is a native Ulsterman and honorary Galwegian now living and working in Dublin. An IT manager by day and dilettante political hack by night, he has also been known to dabble in fundamental physics and musical theatre.

Twitter: @andrewgdotcom