I remember reading Purity and Danger when I was a teenager and thinking it was fascinating. Reading the obituary of the author of it, the anthropologist Mary Douglas, by Geoff Mulgan on Prospect's web exclusive section has made me feel I should re-read it, and other books of hers besides. Going by Mulgan's summary of her cultural framework and its use by Michael Thompson and Marco Verweij in their book on public policy, I am struck by how much of an 'Individualist' ( as opposed to being egalitarian, hierarchical or fatalist) I am in terms of my views on climate change and immigration. But I believe in a spot of hierarchical intervention to tame individualists like me, a mix of policy approaches, which is also what Mulgan, Thompson and Verweij conclude.
I am also intrigued by her theory on enclaves and how this could affect strategies for dealing with terrorist cells. It sounds very plausible that these enclaves are fragile, prone to splits and sectarianism, and strengthened by feeding off the hostility of outsiders to the enclave. So defeating terrorism may involve being less hostile to and not attacking enclaves head on with declarations of war, as this only strengthens their 'wall of virtue'.