There is an unresolved stand-off between ontological naturalism and phenomenological thought regarding the question whether normativity can be reduced to physical entities. While the ontological naturalist line of thought is well established in analytic philosophy, the phenomenological reasoning for the irreducibility of normativity has been largely left ignored by proponents of naturalism. Drawing on the work of Husserl, Heidegger, Schütz, Stein and others, I reconstruct a phenomenological argument according to which natural science (as the foundation of naturalization projects) is itself (...) a part of the essentially normative life-world to the effect that ontological naturalism faces a bootstrapping problem. I aim to demonstrate that this stand-off is grounded in a deep disagreement about the possibility of reduction. I close by arguing that this deep disagreement turns on the question which conception about the nature of (natural) science is true. This result pits a perfectionist model of science (implied by ontological naturalism) against a pragmatist conception of science (in favour of the phenomenological argument). The motivation is that transforming the disagreement about the controversial principle into a disagreement about conceptions of science may help to offer a foundation for different attempts at solving the stand-off. (shrink)