Possible-world theory, then, assumes that human thought and action are unlimited. Orr’s distinctly limited futurity means that the alternative worlds that he dreams fail to coincide with the principle of possibleworld theory—that certain conditions of the present world can be varied intentionally and in a controlled way without changing any other conditions. In the context of a strongly deterministic understanding of human nature—where, for example, God is constantly at work directing the most minute human actions—such possible-world thinkingwould be largely absurd. When Leibniz formulates possible-world thinking in part to explain how God has chosen the best of all possible worlds for us to inhabit, he certainly is proposing a certain kind of personal “substance” that includes “everything that has happened to him and marks of everything that will happen to him.” 14