For the Enlightenment ‘science’ was a powerful weapon to hurl against the forces of darkness. Nowhere was this potency more evident than in the achievements of natural science. In a celebrated snatch of verse Alexander Pope captured the impact of the greatest scientist:

For thinkers of the Enlightenment, with Scotland at the forefront, Newton's achievement was both a model and a challenge. He had shown what could be done and how to do it. The challenge was to emulate his work; to achieve for the moral or social sciences what he had done for natural science. Newton himself speculated on precisely these lines. In his Optics he remarked that if, through pursuit of his method, natural philosophy becomes perfected, so, in like fashion, ‘the bounds of Moral Philosophy will be also enlarged’ (Qn. 31 (1953: 179)). Clear proof that this remark did not go unheeded is provided by its presence on the title-page of George Turnbull's The Principles of Moral Philosophy (1740). (Turnbull even worked it into his Treatise on Ancient Painting (1740): 134.)

Turnbull was not alone in following Newton's agenda. What this shared aspiration reveals is that the social theorists of the Scottish Enlightenment should not be identified as a breed apart from social scientists. For the Enlightenment as a whole any sharp such division would have seemed perverse. Of course some discrimination can be made. There is a difference between the laboratory-based experimental science of Cullen or the mathematical investigations of McLaurin and the work of Turnbull. Nevertheless it is important to appreciate that the Scottish social theorists were engaged in a scientific enterprise as they understood it. The assumptions and character of that enterprise are the subject of this chapter.

A: Baconianism

The Enlightenment was the heir of the ‘scientific revolution’ of the seventeenth century. In Scotland this legacy can be plotted via the changes in university curricula. For example, in Aberdeen between 1660 and 1670 Aristotle was replaced with Descartes and Cartesianism was in turn superseded by Newton between 1690 and 1710 (Wood 1993: 6-7). The story is much the same in the other Scottish universities (cf. Shepherd 1982). Newton was not alone; Locke and Bacon also made an impact.