It looks like I’ve deleted the original of this post. I’m going to try to reconstruct it.
I was very surprised to find out the main way opponents win sumo bouts isn’t by pinning, as in Greco-Roman wrestling. While that can happen, much more frequently someone pushes their opponent out of the ring.
What occurred to me was that often, in disputes today (especially political), we see the same thing — not persuasion by merit, but tarring one’s adversary with beliefs “all reasonable people” must abhor. Famously, portraying someone as a Nazi is known to work, even though in recent years that runs afoul of Godwin’s Law. Sexism, racism, socialism (at least in the US), communism… all of these accusations are meant to shortcut real argument (“…a connected series of statements, intended to establish a definite proposition.”), and just throw the other person outside the ring.
I am aware of the irony that in writing this, and explaining what I mean if I characterize someone’s speech as a “sumo move,” I am recursively doing the very same thing. But sometimes, that’s how it goes.
EDITED TO ADD: My wife Ulrika, a former graduate student of philosophy, notes the following. I think it’s worth adding.
Except that it is neither recursive nor ironic to point out a sumo move.
What a true sumo move (and it isn’t argumentation, it’s propaganda — re-setting the Overton window so that a particular subject won’t be subject to argument in the first place) does is leverage social pressure and people’s sense of decency/shame to make an entire subject unavailable for discussion by casting that subject as taboo in some way. Sumo moves attack the character of anyone who broaches the subject, thus kick the entire topic outside the ring.
Conversely, observing that a sumo move has been used does nothing to prevent the topic it’s applied to from being discussed. Noting a sumo move is meta-analytic. It talks about the way that a subject is being discussed and, rightly, moves the discussion back to the actual subject, rather than the character, motives, and mental state of the people discussing it. Now, it may be true that an honest broker may experience some shame once they admit to themselves that they have been using an illicit tactic, but eliciting shame isn’t the point of pointing out a sumo move. It absolutely is the point of using one.