The fifth and last essay is devoted to a criticism of the various philosophical systems known at the time of the author. Judah attacks by turns the Aristotelian cosmology, psychology, and metaphysics. To the doctrine of emanation, based, according to him, upon the Aristotelian cosmological principle that no simple being can produce a compound being, he objects in the form of the following query: "Why did the emanation stop at the lunar sphere? Why should each intelligence think only of itself and of that from which it issued and thus give birth to one emanation, thinking not at all of the preceding intelligences, and thereby losing the power to give birth to many emanations?"