Abstract
Are institutional principles of justice subject to a minimal realism constraint to the effect that, in order to be valid, they must not make wildly unrealistic demands? Most of us say “yes.” David Estlund says, “no.” However, while Estlund holds that 1) institutional principles of justice are not subject to a minimal realism constraint, he accepts that 2) institutional principles of justice are subject to an *attainability constraint* to the effect that, in order to be valid, they must not make demands we are unable to meet; and 3) what he calls “institutional proposals” are subject to a minimal realism constraint. I argue that these three theses do not represent a plausible combination, at least given Estlund’s account of the principle/proposal distinction. Given this account, Estlund is either wrong to reject a minimal realism constraint on institutional principles of justice, or wrong to accept an attainability constraint on institutional principles of justice and/or a minimal realism constraint on institutional proposals. Either way, this has significant implications for the plausibility of his overall case against the minimal realism constraint on institutional principles of justice.