 Even if the use of abduction in Boyd’s argument might have led to the conclusion that abduction is not reliable, one may still have worries about the argument’s being rule-circular. For suppose that some scientific community relied not on abduction but on a rule that we may dub “Inference to the Worst Explanation” (IWE), a rule that sanctions inferring to the worst explanation of the available data. We may safely assume that the use of this rule mostly would lead to the adoption of very unsuccessful theories. Nevertheless, the said community might justify its use of IWE by dint of the following reasoning: “Scientific theories tend to be hugely unsuccessful. These theories were arrived at by application of IWE. That IWE is a reliable rule of inference—that is, a rule of inference mostly leading from true premises to true conclusions—is surely the worst explanation of the fact that our theories are so unsuccessful. Hence, by application of IWE, we may conclude that IWE is a reliable rule of inference.” While this would be an utterly absurd conclusion, the argument leading up to it cannot be convicted of being viciously circular anymore than Boyd’s argument for the reliability of abduction can (if Psillos is right). It would appear, then, that there must be something else amiss with rule-circularity.