 Naturally, the act-set of ⟨opening the window &amp; shutting the door⟩ is the best that Tom can do in the circumstances he is in at the start on the warm day in question. Given Castañeda’s argument, Tom is obligated to ⟨open the window⟩ and he is obligated to ⟨shut the door⟩. But if he is obligated to do each of them, then ⟨opening the window⟩ must produce more net good than any alternative and ⟨shutting the door⟩ must produce more net good than any alternative. But, Castañeda claims, each of these acts cannot be uniquely optimific.