 I noted that Spinoza could explain why a particular finite mode exists by appealing (in part) to other particular finite modes, namely its actual causes. But Spinoza could not explain why this series, as opposed to some other series, exists by appealing to other particular existing modes. This would be akin to explaining why an entire series of causes exists by appealing to one of those very causes. We aren’t asking why any particular mode exists, but why this whole series, and not some other series, exists. Appealing to yet another contingent fact appears to get us nowhere towards accounting for the  entire set of contingent   facts.[12]