Is there a word for distracting someone from the topic of the argument, and using the authority they have established in the mean time to (fallaciously) prove their original point?
An example
I claim that the language of Schoenberg's innovations do not refer directly to life. I can provide a number of quotes, e.g. Schoenberg begins an essay
or opinion on his music:
or a comment in Pauline Johnson's Marxist Aesthetics, that "the discovery of the correctness of the work's representation of social life is a task for the specialist critic."
They reply with just the one equivocating quote:
“It may be that Schoenberg’s final loosening of tonal ties bore some relation to events in his personal life”
I reply to repeat that perhaps I am wrong, that I know very little about music. They then start arguing about 'certainty': alternative logics, Godel, Hegel, paradoxes of self reference etc. (in the mean time committing to the existence of everything we can conceive of). And they seem to think that they have proven their point, in this mess: that I'm wrong about Schoenberg!