 For Stewart such enquiries are of practical importance, for by them “a check is given to that indolent philosophy, which refers to a miracle, whatever appearances, both in the natural and moral worlds, it is unable to explain” (Smith 1795, p. 293). Stewart uses the term ‘conjectural history’ for the sort of history exemplified by Smith’s account of the origin of language. Conjectural history works against the illegitimate encroachment of religion into the lives of people who are too quick to reach for God as the solution to a problem when extrapolation from scientifically established principles of human nature would provide a solution satisfying to the intellect. Knowing what we do about human nature, about our intellect and will, our emotions and fundamental beliefs, we ask how people would have behaved in given circumstances. Love and hate, anger and jealousy, joy and fear, do not change much through the generations. Much the same things, speaking generally, have much the same effect first on the emotions and then on behaviour. Dugald Stewart formulates the principle underlying conjectural history: it has “long been received as an incontrovertible logical maxim that the capacities of the human mind have been in all ages the same, and that the diversity of phenomena exhibited by our species is the result merely of the different circumstances in which men are placed” (Stewart 1854–58, vol. 1, p. 69).