Divine simplicity is the concept that God does not exist in parts but is wholly unified, with no distinct attributes, and whose existence is synonymous with His essence. The doctrine of divine simplicity is related to the doctrines of divine aseity, transcendence, and unity. Augustine, Anselm, and Aquinas all defined and promoted the doctrine.
According to divine simplicity, as traditionally understood, God is the center of all divine attributes, without form or physical representation. Divine simplicity is the argument that God does not possess qualities; He is those qualities. For example, God does not have existence; He is existence itself. Omniscience is not something God has; God is omniscience. First John 4:16 says, in part, “God is love, and the one who abides in love abides in God, and God abides in him.” Divine simplicity sees that statement as validating the point that God does not possess loving attributes; rather, He defines the very concept of love.
Further, divine simplicity teaches that what seem to be God’s various traits are in reality indivisible and indistinguishable. God’s love is the same as His mercy, which is the same as His knowledge, which is the same as His justice. This would have to be true, because of the principle of transitivity: if a = b and a = c, then b = c (if God = love and God = existence, then love = existence).
Traditional theists (those who believe that a God or gods do exist) and deists (those who believe that God created the universe and then left it alone) may have few objections to the concept of divine simplicity, but there are some serious difficulties with it. Dr. William Lane Craig has dissected the four major claims of divine simplicity (www.reasonablefaith.org/divine-simplicity, accessed 6/5/2017):
1. God is not distinct from His nature. This claim can be accepted as true because it also describes angels. Heavenly beings are who they are, without a sin nature and the qualities that follow that sin nature.
2. God’s properties are not distinct from one another. This claim cannot be truth, because God is a Person, though Spirit, and as such expresses different characteristics in different situations. For example, rejection and acceptance cannot be present simultaneously. God rejected Eliab from being king (1 Samuel 16:7). He could not at the same time accept Eliab as king. Those properties are distinct from one another. Also, existence cannot be identical to omniscience, since there are many things that exist yet are not omniscient.
3. God’s nature is not distinct from His existence. This statement is also problematic. Existence is a characteristic of God, but it does not define God. If God’s nature were identical to His existence, then He would be simply the act of existing; in other words, God would not really have an essence at all. This idea, says Craig, “is unintelligible.”
4. God has no properties distinct from His nature. This claim appears to be the most troublesome, as it implies that God’s qualities, including the choices He makes, exist unrelated to outside elements. For example, God willed that the Son die for sin (Isaiah 53:10). But the question arises, what if God had not created the world? Would the Son’s death still be part of God’s will? Divine simplicity says, yes, because His nature would be unchanged.
Divine simplicity is true in that God is simple enough for a child to accept (Luke 18:17). But His nature is complex and multi-faceted. As has been said, if God was small enough to fit inside the human brain, He would not be big enough to be God.
The major problem with the concept of divine simplicity is that it portrays the Lord as an idea, rather than a Person. The Person of God presents Himself to us in human, not metaphysical, terms. He calls Himself a Father (2 Corinthians 6:18). He uses earthly comparisons to describe His attributes (Luke 13:34; Hosea 1:2). And He documents His range of emotion and responses to our obedience or rejection of Him (2 Kings 22:17; Zephaniah 3:17). When Jesus came to earth (Philippians 2:4–11), He shattered any ideas that God was merely a concept. Jesus brought the complexity of the Creator into a humble carpenter’s home, with hands and feet, eyes and mouth. He showed us what God is like, and faith means we take Him at His word (John 10:30; 14:9–11).