This essay examines the role that the theory of “first principles” plays in Newman's critique of Locke's cognitive-ethical norms. The first section examines in detail Newman's strategy against Locke and argues that there are, in fact, two distinguishable strategies, each with a different concept of the nature and epistemic function of “first principles.” The second section retails examples of what Newman considered to be “first principles” and discusses Newman's claim that our acceptance of these principles is “instinctive.” The final section raises the question of the justifiability of “first principles” and, by reintroducing the distinctions drawn in the first section, argues that Newman can distinguish between “first principles” and unwarranted prejudices and, simultaneously, maintain his criticisms of Locke.