 Monotony states that consequences are robust under the addition of information: if \(\phi\) is a consequence of \(\Sigma\) then it is also a consequence of any set containing \(\Sigma\) as a subset. Most of scholarly attention has been paid to the type of dynamics underlying defeasible reasoning that results in violations of Montony due to the retraction of inferences in view of conflicting new information. It has been called the synchronic  (Pollock 2008)  or the external dynamics  (Batens 2004)  of defeasible reasoning. 