A naturalistic impulse has taken speculative analytic metaphysics in its critical sights. Importantly, the claim that it is desirable or requisite to give metaphysics scientific moorings rests on underlying epistemological assumptions or principles. If the naturalistic impulse toward metaphysics is to be well-founded and its prescriptions to have normative force, those assumptions or principles should be spelled out and justified. In short, advocates of naturalized or scientific metaphysics require epistemic infrastructure. This paper begins to supply it. The author first sketches (...) her conception of suitably naturalized or scientific metaphysics. She then lays out a number of candidate epistemic principles centring around the notion of theoretical constraint. The author offers several arguments for the principles, based on statistical likeliness, agreement, falsity avoidance, and methodological efficiency and inefficiency. Finally, she shows how scientific metaphysics satisfies the epistemic principles and is therefore preferable to its traditional rivals. (shrink)