The doctrine of R. Cordovero is a summary and a development of the different trends in Kabbalah up to his time, and his whole work is a major attempt to synthesize and to construct a speculative kabbalistic system. This is done especially in his theology, which is based on the Zohar, and in particular on Tikkunei Zohar and Ra'aya Meheimna. Since R. Cordovero considered these texts to be by one and the same author, he felt constrained to harmonize their different and at times even opposing conceptions. R. Cordovero follows Tikkunei Zohar in his conception of G-d as a transcendent being: G-d is the First Cause, a Necessary Being, essentially different from any other being. In this concept of G-d, R. Cordovero is obviously drawing upon the sources of medieval philosophy (especially Maimonides). In accordance with the philosophers, R. Cordovero maintains that no positive attribute can apply to the transcendent G-d. In his opinion, the philosophers had attained an important achievement in purifying the concept of G-d of its anthropomorphisms. Yet, R. Cordovero stresses that the essential difference between Kabbalah and philosophy lies in the solution of the problem of the bridge between God and the world. This bridging is made possible by the structure of the Sefirot ("Emanations") which emanate from G-d.