The fundamental reason for a left-wing sect to exist is its own existence; it is its stubborn particularity in a world of conformist drudgery. The sect is in that world but not of it. It proclaims its fidelity to a cause incomparably greater than itself, but couches that fidelity in terms which produce a self-enclosed priestly order, whose very existence is the best guarantor against the encroachments on all borders by a bourgeois world whose business is to consume everything, like the mutagen-McGuffin that spreads among the masses in the currently fashionable zombie-apocalypse scenario. Both the professed desire to shake the world and the enclosure of members from it fail, and it is the interpenetration of these failures that provides the sect with its particular logic.
This presents a difficulty: between the singular and the universal, there is the particular. The sect has to be unique, but it has also to be a sect, among others. The solution was named, if not discovered, by that incomparably representative practice of latter-day bourgeois society - that is, marketing. The logic of the unique selling point dominates advertising copy and much more; but it is fundamentally about appearance. It does not matter if some brand of shampoo really does protect the colour of your hair more than another; indeed, it does not matter if colour did not occur for a second to the luckless chemical engineers sweating in the basement. The sect's unique selling point does not have to be unique (it almost invariably isn't), nor does it even have to exist (it very often doesn't). The matter is still more acute with the sect than with shampoo; the value embodied in a commodity has to be realised to be value at all. Someone has to buy. The sect, on the other hand, is quite capable of existing with only one member (normally an ex-member of a larger one); indeed, in some ways, this is its natural state, though the reduction to an absolute individuality frustrates the universal claim of the communist project.
The selection of the USP - in more archaic terms, the shibboleth - is most often unconscious, and the result of the play of contingency. Certainly, there is no need for the aspiring sectarian to give it much active thought. It has to do with the impossibly detailed history of the splits and fusions, the innumerable personal relationships consummated and destroyed, that constitute the daily life and microhistories of the far left. What matters is not the particular theory and theoretical critiques ostensibly at issue, but the ripples in the water that drive people towards, and away, from each other. From this elemental basis, political clarification can and often does result - but obliquely, for the USP appears to the sect to be a means of bypassing the particular to the universal logic of history; and temporarily, for the disputes between tendencies which are necessary to throw up new knowledges quickly harden into a competition of dogmas, in which discussions occur to a script written sometimes years ago.
