Just stumbled on a beautiful paragraph in The Savage Mind by Claude Levi-Strauss. This follows discussion of the rich vocabulary the so-called savages have for their flora and fauna, often distinguishing, for instance, over a dozen of species of ants. The witch doctors and shamans freely mix their extensive knowledge of herbs with magic and other unscientific paraphernalia; this has sometimes been presented as a stepping stone to more scientific knowledge by a process of keep-what-works. Levi-Strauss adds nuance to this view (p 13).
I am not however commending a return to the popular belief (although it has some validity in its own narrow context) according to which magic is a timid and stuttering form of science. One deprives oneself of all means of understanding magical thought if one tries to reduce it to a moment or stage in technical and scientific evolution. Like a shadow moving ahead of its owner it is in a sense complete in itself, and as finished and coherent in its immateriality as the substantial being which it precedes. Magical thought is not to be regarded as a beginning, a rudiment, a sketch, a part of a whole which has not yet materialized. It forms a well-articulated system, and is in this respect independent of that other system which constitutes science, except for the purely formal analogy which brings them together and makes the former a sort of metaphorical expression of the latter. It is therefore better, instead of contrasting magic and science, to compare them as two parallel modes of acquiring knowledge. Their theoretical and practical results differ in value, for it is true that science is more successful than magic from this point of view, although magic foreshadows science in that it is sometimes also successful. Both science and magic however require the same sort of mental operations and they differ not so much in kind as in the different types of phenomena to which they are applied.
The same, I suppose, applies to religious thought, with its own internal logic. What to an outsider seems bizarre seems perfectly justified and coherent to the insider.