Contrary to a popular reading of his modal epistemology, Berkeley does not hold that inconceivability entails impossibility, and he cannot therefore argue the impossibility of mind-independent matter by appealing to facts about what we cannot conceive. Berkeley is explicit about this constraint on his metaphysical argumentation, and, I argue, does respect it in practice. Popular mythology about the ‘master argument’ notwithstanding, the only passages in which he might plausibly seem to employ the principle that inconceivability entails impossibility are those that (...) argue for the inseparability of primary from secondary qualities. However, an alternative reading of these texts is available that is both consistent with Berkeley's express modal epistemology and credible in its own right. (shrink)