Which argument posits that a perfect Being must exist because we can conceive of such an entity?

The argument that posits that a perfect Being must exist because we can conceive of such an entity is the Ontological argument. This philosophical argument asserts that if we can imagine or conceive of a perfect being, then that being must exist in reality. The reasoning behind this is based on the notion that existence is a necessary component of perfection. Therefore, if God, defined as the greatest conceivable being, can be imagined, then it follows that God must exist; otherwise, there would be a flaw in our conception of God as being the greatest.

Each of the other options relates to different foundational aspects of theology and philosophy. The Cosmological argument discusses the cause of the universe and insists that there must be a first cause, typically identified with God, but does not derive the existence of God from the concept of perfection. The Teleological argument focuses on design and purpose found in the universe as evidence of a designer but again does not rely on the idea of conceiving a perfect being. The Moral argument posits that moral values and duties must originate from a moral lawgiver, connecting morality to God's existence, but does not make the case based on the concept of perfection as the Ontological argument does.