Abstract
Thomas of Aquino, from the time he wrote his commentary on the ’Sentences’ through writing the ’Summa of Theology’, recognized how far beyond Aristotle’s was the rational theology of Avicenna. After perfecting his approach to proving the existence of God in the "five ways," Aquinas further developed Avicenna’s organization for treating God’s nature by simplifying Avicenna’s often convoluted thought and added his own developments in content and order. In sum, Aquinas’s treatment of God’s nature depends closely upon Avicenna’s treatment of the subject in his ’Metaphysics’ 8.3-7, even more so than upon Aristotle. This conclusion can be seen by comparing the doctrines of Aristotle, Avicenna and Aquinas on the divine nature