Farabi in his book entitled Al-Horuf (the words) has mentioned three meanings for “existent” such as “categories”, “true” and “autonomous from the external essence” and maintains that the last two meanings are the main meaning of the “existent”. In order to preserve the philosophical position of the technical meaning of the “existent”, he believes the application of “existent” is as a connective between subject and predicate in decisive affirmative propositions, and in Arabic language is equivalent to the verbs کان/یکون. He also maintains the “existent” which means “autonomous from the external essence” has two kinds of essence, i.e. divided or undivided one. In the divided essences the existence of a thing with its whole essence is in an undetailed way (like human), and “existence” is either the whole essence in a detailed way (like intelligent animal) or components of essence (like animal or intelligent). He gathers all of the debates in (هل/ do/does). In philosophy, this question accompanies by the “existent” and it is either predicate itself or interconnector between subject and predicate. With regard to the meanings of the “existent” in both of these questions, there is a problem of truth in the first place. After knowing the truth, the question which starts with “هل” is used for the essentials of subject which consists of its nature and essence which causes its external autonomy from other beings.
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