 Kaye suggests that two related concepts of vice are at play in Mandeville's formulation.Christianity taught that a virtuous act was unselfish, and the philosophy of Deism suggested that the use of reason was virtuous because it would naturally reveal theological truth.Mandeville looked for acts of public virtue and could not find them, yet observed that some actions (which must then be vices) led to beneficial outcomes in society, such as a prosperous state.