 Fârâbî does not accompany the initial thesis of the Perfect City, “The first being [mawjûd] is the first cause of existence [wujûd] to all other beings [mawjûdât]”, by any explicit proof. What is his strategy for convincing the reader to accept it? On the face of it, there are several ways in which this thesis could be falsified. There might be no first being, because every being has another being prior to it, ad infinitum. Or there might be many beings each of which is “first” in the weak sense that it has nothing prior to it; in which case no being will be “first” in the strong sense that it is prior to everything other than itself. (We might also want clarification of what priority-relation Fârâbî is talking about. He does not explicitly say, but he seems to mean roughly what Aristotle calls priority in being by contrast with priority in time and priority in definition. X is prior to Y in being if X can exist without Y existing but not vice versa, or if neither can exist without the other existing but X is the cause of Y’s existing.) If there is some X which is “first” in the strong sense that it is prior to everything other than itself, Fârâbî seems to think it will be clear that X is the first cause of existence, either immediately or by a chain of intermediate causes, to any other being Y, because every being other than the first will have some cause (distinct from itself) of its existence, and because, if (as Fârâbî assumes) there can be no circles or infinite regresses of such causes, the chain of its causes can only terminate in the first being X. Fârâbî says nothing here about the infinite regress problem (although he is certainly aware of the issue, and we can make plausible guesses about why he thinks the objectionable infinite regresses do not  arise).[47]  But he has a clear (although not obviously successful) strategy for showing that there cannot be many things each of which is “first” in the weak sense that it has nothing prior to it, and therefore nothing which is prior to everything other than itself. Fârâbî does not immediately draw this conclusion: rather, it is supposed to follow from a series of inferences he makes about what anything that is “first” must be like.