The main task of this paper is to come up with an epistemic theory that accounts for a reasonable disagreement in law. To fulfil that task two major steps have to be taken. First, the general epistemic account of a reasonable disagreement has to be developed. Second, this account may help analyse various types of legal disagreements (empirical and theoretical). Having taken these steps I finally argue that legal argumentation serves rather as an expression of our practical need to defend a particular position in legal disagreement, than as an objective instrument helping to reveal any metaphysical truth about law itself. This position however, backed by an appropriate epistemic theory (like A. Goldman’s “objectivity-­‐based relativism”), allows parties to construe this practical rationale of argumentation as theoretically important and thus wholeheartedly engage in reasonable legal peer disagreement (where due to epistemic requirements they should simply suspend their judgment).