 The absurdity Spinoza points to is actually the putative absurdity of the non-existence of a being according to whose concept it is infinite and supremely perfect. But why accept that the concept of Spinoza’s God is internally consistent? If Spinoza fails to justify this assumption, his ontological argument would fall victim to Leibniz’s complaint that even if otherwise successful, (pre-Leibnizian) ontological arguments prove only a hypothetical truth: if God is a possible substance, then God necessarily exists. Spinoza’s argument, absent a justification of (16), fails to establish the possibility of God before asserting the necessity of God’s existence.