This paper argues that Rawls’ original position entails an inadequate conception of knowledge and enquires how this affects the robustness of the the impartiality model. A view of knowledge as separate and detachable from (a too independent) mind as it appears in the original position is contrasted with a more constitutive approach Rawls has had in his first article Outline for a decision Procedure in Ethics. There, the competent judges are intellectually virtuous rather than simple possessors of knowledge. First, I argue that a more constitutive approach is inconsistent with the requirement of symmetry and that even if Rawls implicitly recognizes it in Political Liberalism, he will not however revise, and consequently weaken, the original position requirements. Secondly, a view of an independent mind affects the original position: presented as a guide of reasoning it specifies not only how to conduct our judgement but also which knowledge is permitted to us and which is disallowed. But if direct doxastic voluntarism is false the original position simply could not guide our reasoning this way. Therefore, provided that arguments of the paper hold, the original position could hardly succeed in expressing the pure procedural justice.