 According to Pritchard, the evidence set of a normal zoo-goer standing before the zebra enclosure will typically include, above and beyond E3, the background proposition that (EB) to disguise mules like zebras would be very costly and time-consuming, would bring no comparable benefit and would be relatively easy to unmask. Suppose s knows P3 on the basis of her evidence set, and competently deduces Q3 from P3 thereby coming to believe Q3. Pritchard’s evidential transmission principle apparently accommodates the fact that s thereby comes to know Q3. For her evidence set — because of its inclusion of EB — sufficiently supports Q3. But the principle of epistemic transmission is not satisfied. Although (i) s has justification for P3 and (ii) she knows that P3 entails Q3, she has justification for believing Q3 in virtue of, not (i) and (ii), but the independent support lent to it by EB. 