 Fârâbî in the Perfect City and Political Regime claims to have shown that there is indeed exactly one such first being, which enters as an essential cause into the quiddities of other things. The claim is not that the First acts on each quiddity, from “outside” the quiddity, to give that quiddity actual existence, but rather that whatever immediately depends on the First is essentially constituted by its act of cognizing the First, so that a full account of what the Second is necessarily involves the First; and lower things are essentially constituted by their relations to these higher things, and so are essentially dependent on the First.