 The case of SDA is also a bone of contention between theorists. Chellas (1975) and Fine (1975) first pointed out that SDA seems intuitively valid, against Lewis’s and Stalnaker’s theories. However, as pointed out by Ellis, Jackson, and Pargetter (1977), SDA and LLE together imply Monotonicity: from \(A&gt;C\), it follows that \(((A\wedge B) \vee (A\wedge \neg B)) &gt;C\) by LLE, and thus by SDA, \((A\wedge B) &gt;C\).