This book has delineated the nature of Hume's own visions of the Enlightenment as an on-going movement in his contemporary Europe, and the ways in which he committed to several central issues of the Enlightenment while keeping his spirit of scepticism alive throughout his political, social and historical analyses. In order not to exaggerate the idiosyncrasy of Hume by presupposing a naïve and caricatured notion of ‘the Enlightenment’, I provide a more enlarged definition of this intellectual movement. The provisional definition of Enlightenment that I have proposed aims, not to exclude, but rather to encourage investigations undertaken on an individual basis, without missing the larger picture. As demonstrated in this book, not a few of Hume's particular arguments were indebted to his predecessors and shared with his contemporaries. Because every philosopher is unique in one way or another, the point is to elucidate as much as possible on what point, in what way, and to what degree we can differentiate Hume's arguments and others’, while recognising the concepts, discourses, mind-sets, sensitivities, prejudices and values they shared with one another. As is the case with almost every thinker, Hume's commitment to some key issues in the Enlightenment discourses should be seen as a matter of degree, but as such it is most revealing. This leads us to investigate the ‘historical’ Hume. What Duncan Forbes observes in his Hume's Philosophical Politics seems still worth listening to: ‘The history of ideas would be easier to write about, more dramatic, if what looked like chiaroscuro did not nearly always on closer inspection cease to be so. The colours always run, and the picture becomes complex and messy’ (Forbes 1975b: 308).

If Hume's ‘spirit of scepticism’ plays a central role in his social, political and historical writings, his singularity as an Enlightenment thinker can be best described, I believe, by delineating the ways in which he remains faithful in his mitigated scepticism throughout the various topics he addresses. I have termed this the ‘Sceptical Enlightenment’ and tried to understand the ‘historical’ Hume through this concept, while endeavouring to avoid the error of explaining this concept by exploiting his ideas.