In Lyra’s universe Dust is a source of great anxiety to the Authority, that is the church. Dust, it believes, is the physical evidence of original sin. Dust comes to us when we grow up and become corrupted by the wickedness of the world, of knowledge. In their version of the Book of Genesis, the serpent is responsible for bringing Dust into the world by tempting Eve to taste the fruit of knowledge of good and evil. Dust is something to be hated and feared.
However, Lyra comes to a different point of view, which by a strange coincidence is also mine: that Dust is positively good. In Northern Lights she sees the adults around her doing terrible things in the name of getting rid of dust, and comes to think that dust cannot be bad. She realises that Dust is everything that is best about humanity - love, kindness, and curiosity - and must be encouraged rather than destroyed. This does not mean embracing evil instead of good: it means understanding that since the loss of innocence is inevitable, we should welcome it and embrace the next stage of our development instead of hiding our eyes from it. Knowing about good and evil is not the same as embracing eveil, though it might look like that to a church that likes to think it has all the answers.
In this video I discuss the nature of dust with Donna Freitas