 but he gives no argument that the First’s existence entails the existence of other things. Rather, he seems to rely on the argument that since other things in fact exist, their existence must ultimately be caused by the First; his main concern is not to show that the First causes the existence of other things, but to show how it causes the existence of other things, and in particular to show that that by which the First causes the existence of other things is identical with its essence, just as that by which the First knows is identical with its  essence.[58]  As Fârâbî says, “it is not divided into two things, such that the substantiation of its essence is by one of them and something else’s arising from it is by the other” (Walzer 1985, 92,3–5): as he says a bit further down, the First does not require an accident or a motion in itself in order for something else to arise from it. (Nor is it affected or moved by something else’s arising from it, since it cannot be affected or moved at all.) Nor, more generally, does the First require anything other than its essence—whether an accident or motion that would inhere in the First itself, or an external instrument or material substrate that the First would cooperate with in producing some effect—in order for something other than itself to arise from it. The First does cooperate with external instruments and material substrata in producing some of its effects, and this is important for Fârâbî in explaining how it can produce a plurality of effects, and how it can produce more and less perfect effects, and how it can produce effects which are connected or “ordered” rather than independent of each other. But the First must be able to produce at least some first effect without an instrument or substratum, or it would not be able to produce anything at all, and in that first case the existence of the First must be a sufficient cause of the existence of its effect.