In Palamite theology, there is a distinction between the essence (ousia) and the energies (energeia) of God. It was first formulated by Gregory Palamas (1296–1359) as part of his defense of the Athonite monastic practice of hesychasmos against the charge of heresy brought by the humanist scholar and theologian Barlaam of Calabria. In layman's terms, God's essence is distinct from God's energies in the same manner as the Sun's essence and energies are distinct. The Sun's essence is a ball of burning gas, while the Eastern Orthodox hold that God's essence is incomprehensible. As the Sun's essence is certainly unapproachable and unendurable, so the Eastern Orthodox hold of God's essence. As the sun's energies on Earth, however, can be experienced and are evidenced by changes that they induce (ex. melting, hardening, growing, bleaching, etc.), the same is said of God's energies—though perhaps in a more spiritual sense (ex. melting of hearts or strength, hardening of hearts, spiritual growth, bleaching to be "white as snow," though more physical and psychological manifestations occur as well as in miracles, and inspiration, etc.). The important points being made are that while God is unknowable in His essence, He can be known (i.e. experienced) in His energies, and such experience changes neither who or what God is nor who or what the one experiencing God is. Just as a plant does not become the Sun simply because it soaked up the light and warmth and grew, nor does a person who soaks up the warmth and light of God and spiritually grows ever become God—though such may be called a child of God or "a god." Eastern Orthodox theologians generally regard this distinction as a real distinction, and not just a conceptual distinction. Historically, Western Christian thought, since the time of the Great Schism, has tended to reject the essence–energies distinction as real in the case of God, characterizing the view as a heretical introduction of an unacceptable division in the Trinity and suggestive of polytheism. (en)