 Subjectivists, who reject the PoI and allow any assignment of initial probabilities as long as it obeys the probability axioms, may respond that it’s perfectly permissible to assign a high initial probability to the hypothesis that our senses are (say) 95% reliable. But they must also admit that it is permissible to assign a high initial probability to the hypothesis that our senses are 0% reliable, i.e., wrong all the time. Subjectivists can say that belief in the external world is justified, but they must allow that skepticism is justified too. Some foundationalists may be able to live with this result, but many seek to understand how experience justifies external world beliefs in a stronger sense—in a way that can be used to combat skeptics, rather than merely agreeing to disagree with them.