Answer: Existence is an aspect of actuality and non-existence (potentiality) is an aspect of lackness, privation and that which has ontological lackness, albeit these two words (non-existence and potentiality) are not synonymous with each other but unless necessitated by a cause, since it is demonstrated that the necessary being is the source of all-that which exist, but existence is gradational as in arabic parlance it is (إن الوجود هُوَ متشكك) the pinnacle of that existence is necessary being (God) meanwhile the latter one being the creation that emenates from him. Necessary being (God) is not composite as composition implies dependence which is privation and possible with respect to existence. But this possibility is not sufficient for the quiddity to enter the realm of existence, because quiddity qua-itself is not merely possible in itself with respect to existence but is also possible in itself with respect to non-existence, therefore, if mere possibility were sufficient, so the quiddity would both exist and not exist simultaneously which is a contradiction not just contradiction but a conjunction of contradiction.
When it is proven that necessary being (God) is devoid of composition it necessarily follows that whatever emenates directly from necessary being (God) is also devoid of multiplicity but not at the plane of its cause, it is first intellect (which realizes itself) that has emenated from that necessary being and it is perfect, because of having mutual affinity (سنخيّة) with the necessary being and it is a known principle that when there is mutual affinity (as there is between every cause and effect) there is privation of existence, being existentially less nobler than its cause (أضعف من علته) as refered to in arabic by the philosphers, but to posit here that the more less-affinity there is, there is weakness that occurs from ontological aspect, because this casual series is infinite but not in the sense that third effect cannot be the primary cause of itself since a causal series consisting of only three parts such that the first term is the cause of the second term without itself being the effect of any cause and is therefore a pure cause and the intermediate part is the effect of the first and is also simultaneously the cause of the end term, this was an explanation with the relation to infinite regress, nonetheless to continue from where we left, that effect is less-nobler than its cause, material realm is the lowest in this hierarchical series hence being most less-affinity with necessary being (God) and being imperfect, but to mention that this is due to affinity as said above that the latter is less nobler and weaker and for God it is impossible from him to emenate plurality or multiplicity (of existents) so the intellects are intermediate cause of the material realm. Since human does not exist beyond material realm except for having a metaphysical (مجرّد) soul and it can be actualized once the affinity and connection (إتصال) increases between the soul and the necessary being.
— Haider Jaffery
Neoplatonic Philosophy 