Buehler's argument seems very tenuous, all he seems to show is that cells respond to their environment which shouldn't come as news to anyone. I don't know anyone who would consider cell migration to be generically random, although it may appear so in certain circumstances, maybe this idea was popular in the late 70's when Buehler started his research.
There is a large disjunction between this and showing volition, motivation and free choice. His evidence is highly circumstantial at best.
Your own argument seems to rest solely in essentially throwing up your hands and giving up on ever knowing anything. There seems to be no evidence that the 'forces' you list as non-materialistic are any such thing. What reason is there to suspect that given sufficient further details these won't seem material processes just as the weather does?
You go on to say that your subjective view on this matter may be wrong but as yet you don't appear to have provided any evidence at all to suggest that your conclusions on this matter are right.
TTFN,
WK
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