Naturalists don't accept metaphysics as ana priori knowledge, prior to science, and believe that there is no extrascientific route to metaphysical understanding. In this view, science, as an empirical study, is prior to metaphysics andmetaphysicians' aim to do metaphysics is wholly within the bounds of contemporary science. In this paper, we aim to show that naturalist's position is not justifiable. In fact, we offer two arguments that show naturalist's position is self-defeating. We shall also show that scientific theories, historically, don't arise according to naturalist's position.