Purity Test

A purity test measures immersion rather than principle, which is why passing one requires agreement with an endo-ideal rather than consistency with any stated standard. Marsh places it inside her account of good and evil, since the idea of good and evil usually describes the structure of an endogroup, goodness is assigned to the most obedient reflector, those who can anticipate the whims of the endo-ideal as their own, and the knowledge considered true is the opinion of the endo-ideal or of endoreality. So what a purity test detects is how completely somebody has internalized that opinion, and anticipating the whim before it is expressed is the highest score. The contrast makes the point. In an exosocial interaction balance is judged on an interactional basis, one exchange at a time, and in an endogroup all virtue is assigned to the endo-ideal and all vice to the negative image, so individual interactions lose their importance as the self expands to include a whole group. There is nothing left to assess a person on except position. This is why purity tests intensify rather than resolve. Since the standard is immersion and immersion has no ceiling, anyone can always be found insufficiently immersed, and the test is available as a weapon against anyone at any time. Marsh lists it among the tactics used to sabotage movements, alongside bikeshedding and concern trolling, since a movement testing its members for purity is testing them for endoreality rather than for contribution.

Purity test is common in political commentary for demands that allies agree on every point, and social movement research studies the same dynamic as factionalism and as the narcissism of small differences, Freud's phrase for hostility between closely related groups. Work on high demand groups documents escalating loyalty demands as a control mechanism. Moral foundations research treats purity as one axis of moral intuition, which is a different sense of the word. Marsh's contribution is the criterion, since identifying what is being measured as immersion in endoreality accounts for both why the tests escalate without limit and why they are so useful to anyone wanting to break a movement apart.