Hakim Omar Khayyam was a peripatetic philosopher but he belived in originality of essence and mentality of existence.
In some of his works he offered three arguments in support of this theory and tried to answer six objections against it. According to Ollar Khayyam, since the concept of existence is a common attribute and the
most evident concept that we have, it is taken as the subject of philosophy. In this theory, the concept of existence is an analogical notion which refers to real, mental and all other form of beings.
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