 Mill’s claim that the value of freedom of expression lies in keeping true beliefs from becoming dogmatic reflects his view that freedoms of thought and discussion are necessary for fulfilling our natures as progressive beings (OL II 20). For instance, Mill appeals to a familiar distinction between true belief, on the one hand, and knowledge, understood as something like justified true belief, on the other hand (II 22; cf. Scanlon 1972; Ten 1980: 126–28). Progressive beings seek knowledge or justified true belief, and not simply true belief. Whereas the mere possession of true beliefs need not exercise one’s deliberative capacities, because they might be the product of indoctrination, their justification would. One exercises deliberative capacities in the justification of one’s beliefs and actions that is required for theoretical and practical knowledge. This is because justification involves comparison of, and deliberation among, alternatives (II 6, 7, 8, 22–23, 43). Freedoms of thought and discussion are essential to the justification of one’s beliefs and actions, because individuals are not cognitively self-sufficient (II 38, 39; III 1). Sharing thought and discussion with others, especially about important matters, improves one’s deliberations. It enlarges the menu of options, by identifying new options worth consideration, and helps one better assess the merits of these options, by forcing on one’s attention new considerations and arguments about the comparative merits of the options. In these ways, open and vigorous discussion with diverse interlocutors improves the quality of one’s deliberations. If so, censorship, even of false belief, can rob both those whose speech is suppressed and their audience of resources that they need to justify their beliefs and actions (II 1).