 On the face of it, the “skeptical” upshot of Hume’s study stands in stark contrast to the strong sense of enlightenment optimism with which the Treatise begins (compare the “Introduction” of the Treatise to Book I’s “Conclusion”). But Locke, for example, is more consistently optimistic. His discussion of the nature and extent of human knowledge is, like Hume’s, preceded and informed by psychological theorizing based—to the best of his ability—on good observational reasoning. Further, Locke insists that it is “[f]olly to expect demonstration in everything” (Locke 1690: IV.XI.10), and he defends the information of the senses as giving us “an assurance that deserves the name knowledge” (ibid., IV.XI.3), notwithstanding the theoretical possibility of our being deceived. This runs counter to Descartes’ infallibilism, of course. But it also illustrates the above-mentioned shift, characteristic of NE, away from perfectly general questions about the nature and possibility of knowledge to understanding human knowledge, given the facts of our powers and situation: