A recurring objection confronting utilitarianism is that its dictates require information that lies beyond the bounds of human epistemic wherewithal. Utilitarians require reliable knowledge of the social consequences of various policies, and of people's preferences and utilities. Agreeing partly with the sceptics, I concur that the general rules of thumb offered by social science do not provide sufficient justification for the utilitarian legislator to rationally recommend a particular political regime, such as liberalism. Actual data about human preference-structures and utilities is required to bridge this evidentiary gap. I offer two arguments to support the availability of such information. First, I contend that ordinary human beings have a clear method of epistemic access to reliable information about commensurable preference-structures. Second, in an attempt to shift the onus of philosophic argument, I show that the utilitarian legislator's requirements do not differ in kind from those implicitly called upon by the sceptical deontic liberal.