in Undetermined Presumption of Equality enjoins that individuals be treated equally in the absence of discriminating information. My objective in this paper is to make this principle more precise, viewing it as a norm of fairness, in order to determine why and under what conditions it should be obeyed. Presumption norms are procedural constraints, but their justification might come from the expected outcomes of the procedures they regulate. This outcome-oriented approach to fairness is pursued in the paper. The suggestion is (...) that in the absence of information that would discriminate between the individuals, equal treatment minimizes the expected unfairness in the outcome. Another suggestion is that, under these circumstances, equal treatment also minimizes maximal possible unfairness, i.e., it is minimally unfair if ‘worst comes to worst’. Whether these suggestions are correct depends on the properties of the underlying unfairness measure. (shrink)