She says, quite accurately, that all languages divide things up into groups or categories or classes. In fact, even to name something is to divide it off from the rest of creation, so I see Frank walking past and think "cat". But naming him so, I am simultaneously naming everything else "not cat", so immediately we have two groups. Our groups become large, variable and complex. Sometimes they overlap. So I have groups labelled human, woman, family, friends, pilgrims, christian; and into all of these I can include Clemency, my wife, and I could name many categories to which she does not belong. Everything is laid out into groups in a way which facilitates our thinking about them and our relating to them.
But occasionally, as Mary Douglas points out, we come across phenomena which don't fit easily into any of our existing categories. Of course the obvious problem here is that our categorising system is deficient, but we never think that because we don't think that our system is artificial and approximate and arbitrary. We think instead that our system is some sort of solid and inviolable participation in the very substance of the universe, and that if there is something that doesn't fit it is the STDF that is the problem. Uncleanness in every culture is about those paradoxical things which we can't squeeze into one of our comfortable categories.
So for example, in Jewish dietary laws pigs are unclean because they cannot be categorised: they have cloven hoofs like ungulates but they don't chew the cud as ungulates are supposed to. These breaches of category provoke feelings of disquiet and repugnance in us. They make the very order of the universe (an order which we ourselves have imposed) seem questionable and they threaten our very sense of self.
Douglas says that the rituals of various cultures are the means by which they deal with these breaches in categorisation and bring order back to the world which they have disrupted.
I have been thinking about Mary Douglas because I continue to be appalled and baffled by the energy that is generated around issues of sexual identity in our church. When the planet is being despoiled; when the 67 wealthiest people in the world have as many assets as the poorest 3.5 BILLION people we in the Anglican church are dividing because some fellow Anglicans are in love, wish to make a life long commitment to each other and have that commitment liturgically blessed? Yes, really.
I look at the indignation and the vitriol and ask "where does this energy come from?" And I think Mary Douglas is right on the money. Homosexuality is an apparent paradox that compromises the linguistic categories of many people who feel a consequential rise in discomfort and repugnance. Of course just as Mary Douglas' analysis is accurate so is her (implied) solution. If this situation doesn't fit your categories, it is your categories which are lacking. Get new ones. Better ones. More accurate ones. Ones that more fully reflect this astonishing, varied, complex universe that our God has made and our Lord has redeemed.