Like the Trinity, the incarnation is often considered to be logically incoherent. While the incarnation may transcend our human understanding, it does not transgress the laws of logic. First, because God created humanity in his own image (Genesis 1:27), the essential properties of human nature (rationality, will, moral character, and the like) are not inconsistent with his divine nature. Though the notion of God becoming a clam would be absurd, the reality that God became a man is not.
Furthermore, it is crucial to point out that though the God-Man is fully human, he is not merely human. Though he took on all the essential properties of human nature, he did not take on that which is nonessential (e.g., sinful inclinations). Indeed, as Adam was created without a proclivity toward sin, so the Second Adam was untainted by original sin. As with his moral perfection, Jesus’ other divine attributes (omniscience, omnipotence, omnipresence, and so forth) were not undermined in the incarnation.
Finally, while Jesus Christ voluntarily refrained from exercising certain attributes of deity, he did not divest himself of a single divine attribute (John 1:14; Philippians 2:1–11; Colossians 1:15–20; Hebrew 2:14–18). With respect to his omniscience, for example, his human nature may have served as a filter limiting his knowledge as a man (e.g., Mark 13:32). Nonetheless, Jesus’ divine omniscience was ever accessible at the will of the Father. In sum, there is no incoherence in the biblical teaching that Jesus became and will forever remain one person with two distinct natures neither commingling his natures nor becoming two persons.
For further study, see Ronald H. Nash, Is Jesus the Only Savior? (Grand Rapids: Zondervan, 1994): pages 84–91; for the definitive philosophical work on this topic, see Thomas V. Morris, The Logic of God Incarnate (Ithaca, NY: Cornell University Press, 1986).