We have seen in the foregoing chapters how Hume appeals consistently and across a variety of subjects to the concept of the imagination, which, though not delineated systematically, he takes to be composed of principles that are wide-ranging in scope and profound in effect. In this final chapter, we turn our attention to the role Hume takes the imagination to play in philosophy, the very activity through which the nature and effects of that faculty are made perspicuous. Philosophy, we should not be surprised to learn, itself depends on and is in certain respects governed by the same principles of imagination that it discovers. Central to Hume's approach is the distinction he draws between its ‘true’ and ‘false’ forms, epithets already applied in the context of history and religion. There are important differences in the way they operate in each case but, in general terms, they denote doctrines and beliefs that, on the side of the ‘true’, emerge from taking a disinterested attitude towards evidence and drawing conclusions that stay within the limits of experience; the same are ‘false’ when these criteria are not met. True or ‘philosophical’ history describes a narrative that preserves past events in their original form, due position and temporal sequence, achieved by historians when they take a critical approach to the testimony they encounter. True religion or ‘philosophical theism’ describes a modest or attenuated deism that involves assent to the experience of design and infers an original source of order that arises naturally from contemplating phenomena beyond our grasp. History is false, by contrast, when corrupted by prejudice of one sort or another, and the same is manifest in the religious sphere when superstition terminates in the corrupt forms of polytheism and popular theism.

As some commentators have rightly emphasised, in the course of applying ‘true’ and ‘false’ to the particular case of philosophy, Hume articulates a sort of proto-Hegelian dialectic, casting himself as a player in his own drama of doubt and self-critique. Philosophy aims at human self-understanding but when it finds itself governed by principles ‘inconsistent with human nature’ – as Livingston understands Hume's insight – ‘it must take account of this discovery and reform itself’ if it is to continue and complete its task.