DEUT203 What is the method for investigating the true nature of God's unity? What knowledge must one have, before one investigates the unity of God? If one seeks knowledge about anything whose existence is in question, one must first ask whether it exists or not. Once the truth of its existence is established, one must then inquire about it: What is it? How is it? Why is it? About the Creator, however, one may only ask whether He exists. Once His existence is verified by way of rational investigation, one then inquires whether He is one or more than one. Once it is established that He is one, one examines the meaning of this oneness, and the different senses in which the term is used. This way, one achieves the perfect assertion of God’s unity, as it says in Scripture: “Listen, Israel: Hashem is our God, Hashem is one” (Devarim 6:4). Therefore, one must first investigate whether or not the world has a Creator. Once it is established that the world has a Creator, Who created it and brought it into existence from nonexistence, one then inquires whether He is one or more than one. After it is established that He is one, one that examines the meaning of “the absolute one” and “the relative one,” and what attributes may be ascribed to the true nature of the Creator. In this way, the acknowledgement of God’s unity-- in one's mind and heart--will be complete, with the help of God. There are three premises from which it can be deduced that the world has a Creator, Who brought it into existence from nonexistence: 1. A thing does not make itself. 2. Causes are limited in number; since their number is limited, they must have a first cause before which there is no other. 3. Anything that is composite was brought into existence. After these three premises are established, the inference to be drawn from them--by one who knows how to apply them and combine them--will be that the world has a Creator, Who brought it into existence from nonexistence, as will become clear, with the help of God, from what we will explain.