In the traditional image of the Dance of Shiva, note that the angles of the legs form two intersecting planes orthogonal to the body's frontal plane. This implies Shiva is simultaneously dancing through many dimensions at once. He inhabits a multidimensional reality, and when we speak of Shiva as destroyer, the larger picture is that Shiva is the Great Deconstructor of realities in the matrix of mutually embedded N-dimensional quantum cosmological systems.
Certainly destruction, as by fire, is one way to purify ignorance. Another is by dismantling or deconstructing it, piece by piece. (I get the feeling that this is what Patrick Fitzgerald is doing.) It is interesting to regard the Shivaic force in this light because it is something we can participate in, not so much in the spirit of the rationalist French deconstructive literary theorists, whose purpose is to use relativistic philosophical strategies to give them power over the tyranny of textual misconstructions, but more as computer programmers debugging code with the purpose perhaps ultimately coming out with a new version. Let's put it this way: if God were Bill Gates, you wouldn't expect World 1.0 to be any good. You wouldn't even begin to take it seriously until World 3.0. I don't know about you but I'm expecting a new release of this buggy world any day now.