The reason why many people distrust car salesmen is that we think car salesmen know something about the quality of a car that they are not telling us. They have incentives to lie: a good car without problems fetches a higher price than a lemon. Surely, a car salesman would like us to simply trust him that the car is a peach. Yet, even if we don’t believe that the salesman is honest, we may still decide to purchase the car. This is because there are mechanisms that help us manage our distrust, such as CarFax reports, warranties, and online feedback.
These mechanisms work reasonably well because the quality of cars is observable. Ultimately, we are going to find out whether a car is a peach or a lemon. This allows us to price warranties and create records of historical performance. It also helps individual car dealers to build up reputations for honesty even if we don’t trust car salesmen more generally. The market for cars does not collapse because we think that car dealers are dishonest.
In the case of religion, the problem is the “inscrutable nature of the good,” as the sociologist Diego Gambetta puts it. Clergymen have no private information about quality. Consumers cannot at reasonable expense discover the quality of promises, such as rewards in an afterlife. This means that the authority of clergy is intrinsically linked to how much we trust them.