What is involved in creating a rational plan for one's life? This article considers the idea of a “rational life plan” and argues that we should not consider a rational life plan as a blueprint for carrying out one's purposes and values. Instead, we should think of the task of living one's life rationally and purposefully as more akin to the project of navigation in unknown terrain, where a few overriding intentions about the intended direction of one's travel are mixed with timely adjustments to obstacles and opportunities. Rationality in living one's life involves thoughtful reflection and deliberation about one's enduring values and purposes, along with incorporation of course corrections as circumstances change.