I think Thurman makes a good point there, and it really throws a spanner in the works for this discussion. Thanks for bringing it up.
Astus (and I) are presupposing a linear view of history, and conventional space-time. I think that maybe these are good methodological suppositions, if only because they are the suppositions most people hold. I think the danger that Thurman points to is that these may be taken to be more than mere methodological suppositions; they may become ontological.....in which case texts and the ideas contained within them must conform to that ontology.
Standard methods of textual analysis do not take into consideration the potential for meta-realities and yogic insights from valid authorities.
Well, historically this was the case with most Buddhist scholars -- they actually did accept that Maitreya transmitted to Asanga a key text. For them the existence of Tuṣita was axiomatic. However, modern scholars tend to look down on classical methods of scholarship as inferior and unscientific.
Modern textual analysis is done with materialist assumptions and a linear view of history. You can note that the little brown natives in cotton loin clothes did believe
that Tuṣita exists, but it doesn't really
exist after all, so suggesting the validity of the aforementioned theory about Maitreya and Asanga is out of the question.
Thurman actually takes a bit of liberty and risk in his statement about the authorship of the Mahāyānasūtrālamkāra. He suggests that assuming Tuṣita and Bodhisattvas don't really exist is just as biased as saying that they do exist.
But there is counter problem too isn't there? If we reject a kind of historicist skeptical hermeneutical approach and just go for traditional religious narratives.....then.......don't you end up getting close to the bible belt terrain in America where everything biblical is just believed.
Ultimately, I think this is a bigger danger than crabby, skeptical, scholars. Like all things, balance is warranted.
Why do people often refer to American Christianity when we talk about religious scholarship? I know some of them are quite superstitious and unreasonable people, but their activities are not really relevant to Buddhism in this context. Yes, we don't want to be unreasonable and dogmatic, but the average Buddhist with any actual study of legitimate
Buddhology is probably not at risk at all of becoming like a bible thumping American Baptist.
So I don't think there is a danger like you suggest.