Translating to 'an investigation', this is the first of two 17th century ethical and rational treatises from present-day Ethiopia. Zera Yacob (Zär'a Ya'eqob, Wärqe) is most noted for his philosophy surrounding the principle of harmony. He asserted that an action's morality is decided by whether it advances or degrades overall harmony in the world. While he did believe in a deity, whom he referred to as God, he criticised several sets of religious beliefs. Rather than deriving beliefs from any organized religion, Yacob sought the truth in observing the natural world. In Hatata, Zera Yacob applied the idea of a first cause to produce a proof for the existence of God, thus proposing a cosmological argument. "If I say that my father and my mother created me, then I must search for the creator of my parents and of the parents of my parents until they arrive at the first who were not created as we [are] but who came into this world in some other way without being generated." However, the knowability of God does not depend on human intellect, but "Our soul has the power of having the concept of God and of seeing him mentally. God did not give this power purposelessly; as he gave the power, so did he give the reality." Yacob's work was continued in a second Hatata by his pupil and patron's son, Walda Heywat (Wäldä Hewat).
Comment: This is a treatise that covers several philosophical themes such as the morality of actions, the proof of the existence of God and a critique of religious beliefs as presented in the religious systems of the modern era. This text provides a good basis for developing knowlege of Ethiopian Philosophy. Therefore, it could be used as a starting point to introduce students to the areas of African and Ethiopian Philosophy. It may also be useful as a tool to explore enlightenment ideals as they predated work by European philosophers, such as Descartes and John Locke.