This article presents an analysis of David Hume's epistemological position faced with explanatory gap problem. What did Hume do? Did he resolve the explanatory gap problem or made it insurmountable? The text falls into two main parts: In the first the author tries to show that Hume's attempt to surmount explanatory gap by his analysis of reason's functions was completely unsuccessful. In the second author outlines an extremely interesting role of so called qualia in Hume's gnoseology, defining it as axiological. Namely qualia of affective segment of mind are treated as constituents of moral and aesthetic values and also as causes of actions in physical world.