A defense (in Plantinga’s sense) against the logical problem of evil requires two components: a metaphysical component, which claims that a certain scenario is logically possible, and a value component, which claims that if the scenario in question were actual then it would be consistent with God’s goodness to weakly actualize a world containing evil. In Plantinga’s Free Will Defense (FWD), the scenario in question is one in which every creaturely essence suffers from transworld depravity (TWD). Now, in both The Nature of Necessity and God, Freedom, and Evil Plantinga’s focus is squarely on the metaphysical component, defending the coherence of Molinism and the possibility of every creaturely essence suffering from TWD. The value component is almost completely ignored. Plantinga supposes that, if every creaturely essence suffered from TWD, then God would create a world with evil, and this would not in any way impugn his goodness. But why does Plantinga think this? I suppose he probably endorses:
(1) God’s perfect goodness consists in his actualizing the best world he can
(2) If every creaturely essence suffered TWD, then the best world God could actualize would contain some evil.