In this paper, I argue that Nietzsche’s published works contain a substantial, although implicit, argument for the will to power as ontology—a critical and descriptive, rather than positive and explanatory, theory of reality. Further, I suggest this ontology is entirely consistent with a naturalist methodology. The will to power ontology follows directly from Nietzsche’s naturalist rejection of three metaphysical presuppositions: substance, efficient causality, and final causality. I show that a number of interpretations, including those of Clark, Schacht, Reginster, and Richardson, (...) are inconsistent with Nietzsche’s naturalism, because they presuppose efficient or final causality. In contrast, I argue that the will to power is not an explanatory theory, but a description of the basic, necessary character of reality, designed to critically reveal and minimize metaphysical presuppositions—to reject false explanations of reality and human behavior. It avoids substance-metaphysics by describing reality as will, a causal process without discrete efficient causes or agents. It eliminates efficient causality by describing events as maximal manifestations of power, rather than as agent-actualized potentialities. Finally, it opposes teleology by describing life as tending toward the activity of resistance as such, rather than toward explanatory end-states, such as the accumulation of power or overcoming of resistances. (shrink)