This article argues that Locke's views about the nature of knowledge, on the one hand, and about the proper regulation of probable judgment, on the other hand, give rise to a radical form of individual epistemic autonomy. Three theses are defended: First, Locke's conception of the nature of knowledge implies that the knowledge of other individuals has little (to no) influence on whether one knows something. Locke denies that knowledge is the kind of thing that could, even in theory, be (...) transmitted by testimony. Second, Locke's treatment of probability and probable judgment gives a specific role to testimonial evidence, but within such strict limits that the probable judgments of others should play no role in influencing the strength of one's own judgments. Third, in his New Essays Concerning Human Understanding, Leibniz recognizes the radicalness of Locke's position and sees this as reason to reject aspects of Locke's account of knowledge and his treatment of probable judgment. Finally, these views have implications for how Locke conceives of collective inquiry and the division of epistemic labor among inquirers. (shrink)