 Fârâbî is particularly interested in applying the “sciences of the ancients”, and particularly metaphysics, to resolve the issues addressed and disputed by the “religious sciences” within Islam, especially kalâm or “dialectical theology”. These issues include whether the world was created in time or has existed from eternity, proofs of God’s existence and of his having no partner or contrary, God’s attributes (knowledge, power, will …) and his action in creating the world, and how his causality relates to the causality of creatures. (Fârâbî systematically addresses these issues, as well as kalâm issues about prophecy, the religious community, and the “return” or afterlife, in his Principles of the Opinions of the Perfect City: see  Section 4  below.) Fârâbî thinks that the arguments about these issues within the Muslim community (and other religious communities within the Muslim world) have been merely dialectical, so that it is equally possible to argue on both sides of each issue. He thinks that if the sciences of the ancients, especially metaphysics, can be reconstructed and practiced according to a demonstrative method, they will be able to resolve these disputes. He thinks, however, that earlier philosophers in the Muslim world, in practicing what they saw as Platonic or Aristotelian philosophy, have argued sub-demonstratively, and so have been unable to resolve the disputes. Fârâbî claims to be the first person in the Muslim world to have mastered Aristotle’s Posterior Analytics and so recaptured Aristotle’s demonstrative method. And he claims to be the first to have understood Aristotle’s Metaphysics, and to have mastered the science of being and its universal attributes which gives the only scientific foundation for making judgments about God and his causality.