Wright’s air pump experiment provides Stephenson with the characters and the central debate of the play, but she turns it into a didactic symbol. The dove survives the controlled experiment at the beginning, but in the end Isobel is not spared. In an image so didactic that it almost cancels out the sentimentality, Stephenson emphasizes in her stage directions that Isobel should take the place of the dove in the staged tableau at the end of the play. The air pump vacuum symbolizes the constricted social environment of Isobel’s existence, one in which a deformed Scots servant girl will inevitably asphyxiate.

The message seems clear: that the socially vulnerable will be sacrificed as science advances. The present day threat of genetic intervention means that it is isn’t just the socially vulnerable who are threatened, but anyone outside the perimeters of the normal. Phil realizes that Kate’s scientific project hopes to see schizophrenics like his Uncle Stan selectively aborted in the future. Tom accuses Kate of elitism: “You don’t understand the world at all, do you? You do all your experiments in a vacuum”.

The play uses the air pump to signal that at the same moment science discovered that a vacuum can be created, it stepped inside away from human ethics, to pursue only its own needs. Stephenson echoes the common belief that Science divided itself from Nature during the 18th century Enlightenment, and that the legacy of this separation today is global pollution on the one hand and the transgenic electro-chemical designer body on the other.