Some have not taken into consideration the principality of existence that much, while some outstanding researchers have supported it and emphasized its extraordinary role. Mulla Sadra, the founder of that theory. himself has seriously defended it and presented several demonstrations in order to prove it. He considers that issue among most significant philosophical objectives. Determination, categories, specific forms, combination of matter and form, recognition of real affairs from mentally-posited ones, secondary intelligible and the problem of knowledge, universals, and natural universal are among questions revolutionarily influenced by the principality of existence- which are to be surveyed in this article.
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