Sayyid Ṣ adr al-dī n Moḥ ammad Dashtakī Shī rā zī seems to be the inventor of the division of composition into unified composition and composition by join in Islamic philosophy. With this division, Dashtakī has expressed a new theory about the composition of material objects from matter and form, as well as the composition of man from soul and body, and considers these compositions as a unification, not simply the parts joining to each other. In this paper, we will present Dashtakī ’ s arguments for the theory of unified composition. We will also examine three objections to this theory and his responses. Finally, we will examine the background of this theory in Bahmanyā r's phrases. Dashtakī believes that when the components in a compound have a real plurality, i. e. each one exists separately from the other, a composition by join is created, such as the composition of a house from numerous clays. But if the components in the compound are united and none of them exists actually and seperately from the others, the resulting composition will be an alliance and union. He believes that in the unified composition, every component is identical to any other component and is identical to the whole. In order to achieve a composition, a plurality is needed and in order to form a single composition, there must be plural components related to each other. An important question is that, principally how is a composition possible, if unified composition comes to existence only when the components are made united with each other and with the whole? In other words, unified composition is not possible, because the first condition, i. e., the plurality of the constituent components, cannot be satisfied. Dashtakī , in order, strives to express a difference between the components in the union compound. He believes that the conditions of the realization and the survival of the components are different, and that is enough for them to be different. In Dashtakī 's point of view, in the unified composition the components are analytical, so are not separated in reality. In other words, the components do not have actual and "in-the-world" plurality, which means that it is our intellect that separates them and looks at them as independent objects. Therefore, unity and identity are in-the-world and plurality and discernibility are analytical and intellectual. Dashtakī 's first argument for his theory in general is as follows: the three major material objects (body, plant and animal) are undoubtedly real compounds. But in these compositions, components exist potentially, and in a unified composition, components do not exist actually. Therefore, these objects are unified compounds. His second argument is that the accuracy of predication implies unity. In the unified composition, the components are identical with the whole, and therefore, the components can be predicated to the composition. In Dashtakī 's view, if A is predicated to B, then it could be concluded that they are identical and unified. The first objection to this theory is that the unity is incompatible with causality. From the perspective of the Peripatetics, form is the cause of the matter, and this is incompatible with the union of the two. In reply, Dashtakī states that in case of causality, there is no need for cause and effect to be two different and discernible entities, but a single entity may be from one aspect the cause and, from another, the effect. In other words, the foresaid causality is analytical causality. When mind analyses something, and then finds analytical components, it can see between those analytical and intellectual components, causality, and find some of them as the cause of the others. The second objection is the incorrectness of the unity in compounds with components not being similar. Only in the compounds having similar parts such as glass, the objection goes, one can accept the unity of matter and form. For example, in compounds such as horses, it is not possible to accept the union of matter and form, because in horses, there are components with different natures, such as bones, flesh and nerves. Unity of these parts with each other and with the whole is not plausible. Dashtakī ’ s reply is to concede that the horse is also a natural unit and has no actual plurality. Components having similar or different natures does not make any difference. According to the theory of unified composition, the horse's components are united with the horse's form and have only analytical plurality. Horse’ s components are just analytical components, not actual, independent ones. The third objection is the incompatibility of the actual existence of components with their unity. But Dashtakī maintains that a unique actual personal entity cannot have actual plural components. He states that compounds such as horses exist objectively, but objective and real existing is divided into two kinds: dependent existence, and independent existence as a single real thing. Therefore, the two characteristics of "being a component" and "being independent" are incompatible and do not come together in a real being. Dashtakī has also quoted phrases from Bahmanyā r to confirm his point of view. Bahmanyā r states that the properties of an animal belong to the whole and compound, not to each component. For example, it is a horse that feels, not its bone or brain, as the eye is also a compound, but seeing is the work of the eye, not the work of any of its components. Therefore, the animal, which is something compound, has characteristics that none of its components have. So the animal is something over and above its components. Bahmanyā r thinks the components in the animal exist potentially. Then he states a general rule: any compound in which unity is real, its components do potentially exist. Therefore, Bahmanyā r considers the body parts of a living organism as a potential being and generally believes that the components of any compound that have true unity are potential. The potentiality of the components in a real compound does not mean that the components are destroyed and a new thing is produced. The components are also available, but they do not have the effects they had separately before the composition comes into existence. In other words, the components form an identity together and therefore have a new effect. It seems that Bahmanyā r has expressed the same idea that Dashtakī is looking for in the theory of unified composition. Therefore, it can be said that before Dashtakī , Bahmanyā r has come up with the thought of a unity. Nonetheless, Bahmanyā r has not explained more about this idea and its effects in the other problems of his first philosophy. Dashtakī is the first who has organized and developed this idea as a philosophical theory.