 Newton lay down the gauntlet in his well-known Query 31 to the Opticks (1704), namely that his methods for deciphering the natural world might prove efficacious in understanding the moral sphere. Many took up his plea to advance the moral sciences. In France, one could name Voltaire, Condillac and Condorcet, and in Britain, Hutcheson, Hume, and Smith. The common conviction was to identify sufficient uniformities to human nature that resulted in manifest patterns, whether in the economic or political sphere. Hume’s associationist psychology and the copy principle implied remarkable uniformity in the machinery of the human mind, while Smith treated the sympathetic regard as akin to gravitational attraction. Both believed that introspection meant that the moral sciences, including economics could become epistemically superior to the natural sciences. As both Hume and Smith pointed out, pre-modern philosophers had endorsed a geocentric universe for thousands of years and in modern times, mistakenly adhered to the system of Cartesian vortices for almost a century. Nothing compared to the occasionalism of Malebranche, that Hume deemed “a fairy land” (Hume 1748 [2000: 57]). In the moral realm, however, we could know right away if something is as fanciful as a system of vortices. Both Hume and Smith were fallibilists about all knowledge, but they each argued that we are more likely to know when we are wrong in the moral sphere than in the physical sphere. Introspection and experience of the world were important assets in this respect. But, as Hume averred, “nature will forever elude our grasp”, and even if we dig more deeply into the microphysical realm, this would simply expose the need for further investigations.