Moral rationalism has long been an attractive position within moral philosophy. However, among empirical-minded philosophers, it is widely dismissed as scientifically untenable. In this essay, I argue that moral rationalism’s lack of uptake in the empirical domain is due to the widespread supposition that moral rationalists must hold that moral judgments and actions are produced by rational capacities. But this construal is mistaken: moral rationalism’s primary concern is not with the relationship between moral judgments and rational capacities per se, but (...) rather with developing a conception objectivity normativity that avoids Platonism. In light of this, I develop an alternative approach to translating moral rationalism into the empirical domain that builds on the common rationalist view that normative requirements are explained by the relationship between agents and the social structures and practices in which they are embedded. I propose that this social conception of normativity can be translated into a scientific framework by interpreting it as a claim about the importance of constraint-based explanation when accounting for norm-governed behavior. In order to develop this point more concretely and show that it is empirically tractable, I turn to research on macaque social organization that highlights the ways in which normative standards are generated by empirically observable social structures. The insights garnered from the macaque case allow me to then locate moral rationalism’s core claims about the relationship between morality and the standards of practical rationality within an empirically plausible framework. (shrink)