Why do reason, science, and history--our most trusted guides--collapse when separated from God? In Unreasonable Doubt, Sergiu Margan argues that the very frameworks skeptics use to dismiss God are only coherent because of him. Reason assumes an order it cannot explain, science presupposes laws it cannot ground, and history depends on testimony it cannot justify without trust. Strip away God, and each discipline falls into contradiction. This is not a book of slogans but a guided exploration of the deepest questions: Can moral values stand without a Lawgiver? Why does science rely on rational laws rather than chaos? How can history preserve truth if human testimony is dismissed? Written in clear, accessible language for seekers, students, pastors, and thoughtful skeptics, Unreasonable Doubt demonstrates that belief in God is not only intellectually sound but essential. It invites readers to see that the very pursuit of truth leads back to the Source of truth himself.