This paper questions two core assumptions pervading the field of General Systems Theory (GST) in order to preserve the ideal of the unity of science advocated by its founding fathers. The author claims that an ontology of levels based on unquestioned emergentist and materialist assumptions leads to a disunity of systems. A metaphysics is proposed to inform GST which is based not on logics but on the nature of reality in order to transcend four antinomies of thought and explain the unity of systems. It is claimed that reality is animated by an internal force that permeates the entire universe, an endless craving for being referred as the will. The will manifests in the universe in the form of substances which have a dialectical charact...