An Avicennan argument for the existence of a Necessary Being

If an essence exists so it self-evidently cannot be impossible in essence because had it been essentially-impossible for it to exist so it could never have existed in the first place, therefore it must either be Necessary or Contingent; now if it is Necessary so this establishes the above assertion, but if it is contingent then it would ultimately lead to a Necessary Being since both circular-causation and infinite regress are impossible. Circular Causation implies that an existent becomes the cause of its cause or in other words that an existent causes its own cause and thereby necessitates its own existence, for instance if 'A' causes 'B' that in turn causes 'A', so by causing 'A', 'B' is actually acting as the cause of its own existence since 'A' is assumed to be the cause of 'B', and by doing so 'B' is actually necessitating its own existence or causing itself by itself, which is impossible since nothing can be the cause of its own existence as that violates the principle of non-contradiction according to which a thing cannot both exist and not exist in the same respect simultaneously, and to assert that 'B' brings into existence the cause of its own existence namely 'A' is tantamount to asserting that 'B' causes itself or that 'B' exists before it exists, and this is inadmissible. Infinite Regress is impossible as it assumes the possibility of a chain of existents every member or part of which is an effect of some prior cause and so on without this chain ending in an existent that is a pure-cause without being an effect of another, but this is impossible because an infinite chain of existents every member or part of which is an effect of some prior cause, and hence contingent in essence, has no reality over and above its parts namely the individual members or effects that constitute it, meaning that any infinite chain of beings will be dependent upon its individual members or parts for making what it is, since it is a composite, and that which depends upon a contingent is itself also essentially-contingent, therefore any such infinite chain despite its infinity will remain a contingent-existent and every contingent is in need of a cause to come into existence. Moreover if 'a' causes 'b' and 'b' causes 'c' so in such a chain 'a' is a pure-cause without being an effect of another, and 'c' is a pure-effect without being the cause of any, and 'b' is both a cause and an effect; now it makes no difference if 'b' is finite in number or infinite, it cannot come into existence unless necessitated by a pure-cause meaning an non-caused cause or 'a'. Now that both circular causation and infinite regress have been demonstrated as being impossible it becomes evident that the existence of a Necessary Being is a necessity.