In French, the verb "to live" designates both being alive and the experience of something. This ambiguity has a philosophical meaning. The task of a phenomenology of life is to describe an originary sense of living from which the very distinction between life in the intransitive sense and life in the transitive, or intentional, sense proceeds. Hans Jonas is one of those rare authors who has tried to give an account of the specificity of life instead of reducing life to categories that are foreign to it. However, the concept of metabolism, by which Jonas characterizes vital activity, attests to a presupposition as to life: life is conceived as self-preservation, that is, as negation of death, in such a way that life is, in the end, not thought on the basis of itself. The aim of this article is to show that life as such must be understood as movement in a radicalized sense, in which the living being is no more the subject than the product. All living beings are in effect characterized by a movement, which nothing can cause to cease, a movement that largely exceeds what is required by the satisfaction of needs and that, because of this, bears witness to an essential incompleteness. This incompleteness reveals that life is originarily bound to a world. Because the world to which the living being relates is essentially non-totalizable and unpresentable, living movement can not essentially complete itself. Thus, in the final analysis, life must be defined as desire, and in virtue of this view, life does not tend toward self-preservation, as we have almost always thought, but toward the manifestation of the world.