The concept of divine simplicity, historically a central doctrine in Christianity, Judaism, and Islam, holds that God is not composed of parts or attributes but is a simple, undivided, and irreducible being. The history of this idea begins with ancient Greek philosophers like Aristotle and Plotinus, was adopted and developed by early Christian thinkers like Irenaeus and Augustine, and was further refined by medieval theologians such as Thomas Aquinas. The doctrine was considered foundational for distinguishing God from created things, upholding God’s self-existence, and providing a basis for monotheism and Christian Trinity doctrine.Â