In his introductory essay on the philosophical sources of The Guide of the Perplexed, Shlomo Pines points out a well-known contradiction between two conceptions of God in Maimonides' theology. On the one hand, Maimonides borrowed the Aristotelian definition of God as the intellect that cognizes itself; on the other, in line with Avicenna's Neoplatonic theory of attributes, Maimonides denied the possibility of saying anything positive about God. Pines proposes two possible solutions; first, that Maimonides was well aware of the contradiction, or, second, that he fell into the contradiction inadvertently. As Pines himself admits, however, neither solution is satisfactory.