 Any genuine consequence relation ought to enable reasoning by cases. If I would infer \(\gamma\) irrespective of what I learned about \(\alpha\), I should be able to infer \(\gamma\) before the matter of \(\alpha\) has been decided. In full generality, Or says that if \(\gamma\) follows defeasibly from both \(\alpha\) and \(\beta\), it ought to follow from their disjunction. Any consequence relation that satisfies Reflexivity, Right Weakening and Or must also satisfy the following principle: