The Ultimate Ideology?

The standard explanation for "purity spirals" is a lack of limits. You can't stop because there's no obvious point at which you should stop. Once you start decapitating aristocrats or denouncing imaginary communists in the American Establishment, how will you know when you've done it enough?

Another factor though surely is the superficiality of Utopian political ideologies. You have to keep going until your dictatorship of the proletariat or Year Zero or whatever has been achieved. And if all you're doing at the moment is making things worse (apparently!) then it must be because you're not doing it properly. And thus the more simplistic the ideology the worse the purity spiral is likely to get - because if a simplistic ideology such as socialism isn't working it can only be because it isn't extreme enough.

Certainly purity spirals are an interesting psychological phenomenon though. They can be political or religious, and whereas they should always be a sign that one's fundamental assumptions are flawed, we all get into them from time to time. Keep doing the same old thing and it will come right in the end. You're just not trying hard enough. And thus indeed adherents of fringe ideologies also tend to fall victim to the sunk costs fallacy. Having invested so much in a cause politically and emotionally, they have to keep going, and to keep going they have to become ever more extreme.

Where does that leave actual politics? There's a sense in which all ideologies are simply pseudo-scientific models of human behaviour, and like all "scientific" theories they are doomed to fail just as man's understanding of the universe must always fail because it is limited. Seen from this perspective then, it is not surprising that when political parties lose elections they tend to become more "extreme" - "doubling down on stupid", as the saying goes. ("If the people didn't like privatisation, or they didn't like tax hikes, or whatever, it can only be because we didn't do it properly - in other words, we should have done it even more.")

The problem of course is that the idea that elections are always won from the moderate centre ground is something of a historical conjuring trick. In reality, British politics have been moving inexorably leftwards ever since the early 1990s. Indeed, the most right-wing Prime Minister of my adult life was and remains one Sir Anthony Charles Lynton Blair, KG. The same magical thinking that leads to purity spirals has led us as a country to impoverish ourselves by spending too much money, and not a single political party with any chance of power at the next election has any plans to reverse gear or even change course.

In practice, unfortunately, we all often end up doing the same old thing - looking for what was lost in the same place over and over again, in the utterly irrational hope that it will just turn up - because in reality we simply have no alternative.

Real life is, it turns out, the ultimate ideology.