Abstract
Avicenna's Philosophia Prima occupies a relevant place in the history of metaphysics. In its first four chapters, we find a definition of metaphysics as wisdom and the more certain philosophy that highlights the scientific character that Avicenna seeks to give metaphysics. The elucidation of the subject matter of this discipline is developed in the debate among its Arab sources, but at the same time, it extends in the historical discussion on the place of God and being in metaphysics. This article presents the definition of metaphysics as the first science, and the establishment of the being as the proper subject of metaphysics, and God as what is sought.