In
Tibetan Buddhism, a small
wheel in which a paper
prayer is inserted, so by turning the wheel the prayer may be
repeated indefinitely. They are powered either by hand or by placement in the wind, supposedly.
In philosophy, a jocular term for an argument which is supposed by its believers to be doing something very profound, but which to others appears to be going round and round forever doing nothing.
The classic example is "Ah, but what is it really?", often accompanied by a smug sense of communing in a deeper spiritual plane than the poor jobbing philosopher or scientist who has nothing to offer but an explanation.
To attempt deeper understanding, greater generality, a more unified or objective approach, these are all laudable goals in discussion. The Tibetan prayer wheel however is something that does not engage with the argument. It does not propose a better alternative, or a more insightful or more complicated or more simple perspective, one which can be compared to the original thought: it simply repeats itself regardless of the original thought.
An attempt to answer it, that is to treat it as if it was a valid question, will come up with another answer, another explanation. But whatever this is, you can attach a 'really' to it and doubt whether that's what it really is.
This is just a verbal trick. To make noises with your mouth is not to make language. To string words together grammatically is not to speak sense. To utter an interrogative sentence is not (necessarily) to ask a question. And to ask a question is not to ask a sensible question, one that has an answer. If a question can not be answered it may be that (i) the answer is not yet known; (ii) the answer in the nature of things is unknowable; or (iii) the question is nonsense. The "Tibetan prayer wheel" is nonsense that has the spurious effect of sounding like insight.
A related fallacy is the No True Scotsman ploy.