 This argument has a general premise: “the cause of the existence of a thing exists along with it” (Ilāhiyyāt, VI, 2, 1, 264–265, 5; VIII, 1, 327, 11); its structure is taken directly, and almost verbatim, from Aristotle. The causal chain is composed—as in Metaph., α, 2, 994 a 1–19—of three elements: the cause (al-ʿilla), and then the effect (or what is caused: al-maʿlūl) and the intermediary or medium (al-mutawassiṭ), which both have a “relationship” to the cause “that consists in being caused” (nisba maʿlūlyya; see  section 4.1).  In a nutshell, the argument is simple: the existence of an effect (which is the cause of nothing) cannot be explained without evoking a First Cause; a cause that is cause and effect at the same time and therefore a medium, would in turn refer to a cause: therefore, no matter how many intermediate terms it includes, the series must always imply an absolutely First Cause: a cause that is a cause for each element of the series and exists together with them.