I am enjoying hearing your thoughts on this, and I agree that this discussion would be a better one once I can post my article.
And yes, I'm aware of Van Beek's arguments, but thanks for the link. The central difficulty with his view is the assumption that he can prove the non-existence of a secret tradition, to which he may not be privvy. One comparison I make is to a visitor to a college campus on Parent's Weekend coming away with no evidence of drug or alcohol use. Because the visitor is dealing with a societal group that is actively conspiring to hide the truth from him, the apparent lack of evidence is completely meaningless - it is simply indicative of a well-kept secret.
Elsdon Best describes a similar secret tradition among the Maori of New Zealand, which like Dogon cosmology centers around the 'po' as a fundamental component of matter. He says that long residence among the Maori is required before sufficient trust is gained to induce the priests to admit the existence of the tradition. So one of my questions to Van Beek is, how can he positively distinguish between a lack of evidence that comes out of deliberate obfuscation, as opposed to a lack of evidence that comes out of actual non-existence of the tradition.
My solution to the dilemma is simply to demonstrate by direct comparison that the cosmology Griaule reports is an entirely coherent form, based on the highly reputable testimony of a top scholar in regard to a tradition that Griaule had no opportunity whatsoever to influence or misconstrue. The cosmology is a coherent form, and it comes out of an esoteric tradition of precisely the kind that Griaule claims to exist among the Dogon. This constitutes direct corroboration for Griaule. It is nonsensical to say that Griaule somehow misinterpreted his Dogon informants and, in so doing, happened to accidentally document a near-exact match for another secret cosmology that I can show is an absolutely legitimate one. It is far more sensible to say that the matching form confirms Griaule's cosmological model, and so suggests that he very accurately reported he Dogon tradition.
The only real wiggle-room left is to adopt the (in my opinion) extreme view that Griaule somehow knew all the initimate details of this other tradition and deliberately and falsely presented them as if they were Dogon. But it seems far more likely to me that Van Beek interviewed a large number of Dogon tribespeople who legitimately know nothing of the secret tradition, and a smaller number of Dogon priests who deliberately lied to him - as both Griaule and Best say they are obligated by the tradition to do - to protect their secret.
As regards lack of knowledge of the Dogon language, it is true that Griaule used a translator. It is also true that his daughter ended up writing the Dogon dictionary based in large part on Griaule & Dieterlen's research.