It occurs to me (I don't really understand why people get so flustered about a metaphysical postulate, but that's another matter) that even if it could be demonstrated that some biological features are too complicated to have come about by chance, that would not logically imply a Designer.
One could postulate, as Aristotle did, that the natural world has an innate tendency to develop in an orderly direction.
Nu, zayats, pogodi!
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