Poison Ivy Wouldn't Have Me Thinkin' Rash

In America, something deemed unsayable is, sooner or later, bound to be said. And it may be said rather more heatedly as a result of its having been a taboo.

Imagine that we could revive a well-educated Christian of the fourteenth century. The man would prove to be a total ignoramus except on matters of faith. His beliefs about geography, astronomy, and medicine would embarrass even a child, but he would know more or less everything there is to know about God. Though he would be considered a fool to think that the earth is the center of the cosmos, or that trepanning constitutes a wise medical intervention, his religious ideas would still be beyond reproach. There are two explanations for this: either we perfected our religious understanding of the world a millennium ago - while our knowledge on all other fronts was still hopelessly inchoate - or religion, being the mere maintenance of dogma, is one area of discourse that does not permit of progress.
With each passing year, do our religious beliefs conserve more and more of the data of human experience? If religion addresses a genuine sphere of understanding and human necessity, then it should be susceptible to progress; its doctrines should become more useful, rather than less.