[Advaita-l] apaurusheyatva of veda-s

[Omkar Deshpande]

Namaskara, 

>Brahman is not something that can be solely deduced; all that reasoning can come up with is only a hypothesis. It is possible to know that there is Brahman only due to the testimony of the Vedas; if they are paurusheya, they cannot be testimony. 

I have a question about this - 
How does a text being apauruSheya serve as a better testimony than a text that is pauruSheya? If it's said that pauruSheya texts may have flaws because of the bias of the author, how are apauruSheya texts guaranteed to be valid merely because of not having an author? It's not merely the absence of bias that makes an authored text valid, but the presence of knowledge in the author as well. In an unauthored text, not only bias, but the merits of the author (knowledge, etc) would also be missing. How then is validity guaranteed?

My familiarity with apauruSheyatva is based on dvaita works, not advaita/Purva-Mimamsa works, and I don't come from an advaita background, so please pardon me if my questions have a well-known answer in the advaita framework. 

Regards,

Omkar