Why does it have to be an
extraterrestrial. Is it not possible
that the same information could be
transmitted by an ancient civilization
that was Earth bound, after a great cataclysm.
It seems to me the ancient alien hypothesis is just
as easily explained this way, without having to travel
hundreds of thousands of light years in a spacecraft.
One rule that I impose on myself as a way of filtering out wishful interpretations is that, whenever possible, an interpretation begin with an explicit statement on the part of the culture I'm studying, and either be affirmed by similar statements from other cultures that share the tradition, or be stated in multiple ways within a single culture.
When we reach the bottom of the correlatable Dogon and Buddhist traditions, both overtly state the same belief - that they received the essential aspects of their cosmology, part-and-parcel with specific civilizing skills, from a non-human source. To date, none of the traditions I study who share key elements of this same apparent system of symbols and myth claim to have received it from a prior culture. All assign it to quasi-mythic knowledgeable ancestors of the sort described by the Dogon and Buddhists.
Adrian Snodgrass, a leading authority on Buddhist symbolism, writes on page 3 of The Symbolism of the Stupa:
"The sacred symbol is deemed to have been "given"; it is revealed to the tradition from a non-human source."
The Dogon priests say their ancestors went so far as to ask their teachers whether they were God (they said they weren't - but the Dogon could consider them "agents of god" if they liked.)
Based on that, in keeping with my policy regarding interpretations, I leave open the possibility - if not likelihood - of non-human involvement. And yes, we could see a similar result if the information had come from a prior civilization (which the Dogon and others imply did exist), but for me, knowledge of things like a reasonable structure and origin for the universe implies a space-capable culture. So in that case, we're effectively the aliens we claim couldn't have existed.