In Dialogues Concerning Natural Religion, Hume explores whether religious belief can be rational. Because Hume is an empiricist, he thinks a belief is rational only if it is adequately supported by experiential evidence. Through discourse, three philosophers, Demea, Philo, and Cleanthes, debate the nature of God's existence. Whether or not these names reference specific philosophers, ancient or otherwise, remains a topic of scholarly dispute. While all three agree that a god exists, they differ sharply in opinion on God's nature or attributes and how, or if, humankind can come to the knowledge of a deity.