The separation of church and state is a necessary part of a modern civilized society. Laws must be made in accordance with the reality that we know grounded in facts that the scientific method has allowed us to uncover. Does this necessarily happen even in so called civilized society? Of course not, secular societies are not much better when it comes to making rational laws and standards, but I do believe they have a better chance of legislating appropriately that religiously addled societies that need to take into account what the great mumbo-jumbo in the sky has to say on the pertinent issues at hand.