Imam Abu ‘Abd Allah (as) On Burhan-e-Inni and Burhan-e-Imkan

Hisham states that off the questions of the atheist from (Imam) abu ‘Abd Allah (as) one was ‘what is the evidence of His existence’? The Imam(as), answered:
”وجود الافاعيل دلت على ان صانعا صنعها ا لا ترى انك اذا نظرت الى بناء مشيد مبنى علمت ان له بانيا و ان كنت لم تر البانى و لم تشاهد“
translation: “The existence of the effects (activities) shows that someone has produced those effects and activities. Consider, when you see a well-constructed building you learn that there is someone who has built it even if you have not seen the builder with your own eyes” [Al-Kafi, kitab-ul-tawhid#215]

The essence [ماهية/ذات] of an existent [موجود] is either such that existence [وجود] is integral to [عين ذات] and inseparable from, it [essence], in which case it can never fail to exist and is said to be Necessary in Itself [واجب بالذات], or its existence is separable and distinct from its essence, in which case it is said to be contingent in itself [ممكن بالذات]. Now assuming the essence of that existent is Necessary in Itself and non-caused so this proves the existence of a Necessary Being [واجب الوجود]; and if the essence is assumed to be contingent in itself, so contingency [امكان ذاتى] is the negation [نفى] of two necessities namely the necessity of existence [وجوب وجود] and the necessity of non-existence [وجوب عدم], which means that an essence is said to be contingent in itself if it is neither necessary for it to exist nor is it necessary for it not to exist, meaning that such an essence is neither inclined towards existence nor is it inclined towards non-existence [عدم], but both existence and non-existence are possible [ممكن] for it; such an essence is in a state of equilibrium, oscillating between being and non-being and therefore is in need of an external agent [فاعل] or a cause [علت] for necessitating its existence by granting preference [ترجيح] to the possibility of its existence over the possibility of its non-existence, and without this preference granting cause or agent [مرجح], there can be no preference of the possibility of existence over the possibility of non-existence and consequently the essence would continue to remain in a state of equilibrium; now the same question reverts to the essence of that agent or cause, such that if its essence is non-caused so it would be Necessary in Itself, but if its essence is contingent so it would also be in need of a cause for its existence and so on, but since infinite regress is impossible so this causal chain must ultimately cease at an existent whose existence is identical and integral to its essence and it is therefore needless of a cause for its being, since it itself is the very Reality of existence [حقيقة الوجود] and a Necessary Being; therefore the existence of the entire contingent realm [عالم امكان] is proof of the existence of a Necessary Being as is mentioned by the Imam (as) “the existence of the effects shows that someone has produced [caused] those effects”.