Ideal interpretation is understanding a text in the best possible way. It is usually used when the text has a canonical status, such as the Bible or the U.S. Constitution. We argue that Zhu Xi’s view about interpreting the Four Books and Ronald Dworkin’s view about constitutional interpretation are examples of ideal interpretation and that their basic principles are similar. Each holds, roughly, that their target text contains moral truth; that the author’s mind requires the mediation of learning; that the purpose of interpretation is not only to lead the reader to the moral truth but to become a better person; that all propositions are about the same moral truth or about political justice; that the interpretation ultimately must come from oneself, purged of prejudices; and that the only correct interpretation is one that captures the original meaning.