That is because you keep asserting that complex, specified information (CSI) has not been "seen." An absurd proposition on the face of it, considering you know how to read. Or is that supernatural, too?
In Dembski's book, he uses an f(x) = x function to show how it cannot gain information. But, that isn't a model of evolution because that isn't how evolution works. Evolution increases variation through mutations, recombination, duplication, gene flow, genetic drift, and gene shuffling and then converges via selection. As this is the basis of his book, the entire point collapses.
Erik Tellgren meticulously deconstructed Dembski's law here along with Tom Schneider.
Anyway, complex biochemical pathways have evolved - without intelligent intervention. (B.G. Hall (1982). "Evolution of a regulated operon in the laboratory", Genetics (journal), 101(3-4):335-44.)
You can read more here.