In becoming embroiled in the period's great scandal of literary authenticity, Hugh Blair and Henry Home, Lord Kames developed a bifurcated way of thinking about the progress of human ‘manners’. The concept is commonplace in eighteenth-century discussions of the development of man to civilization, and the publication of the Ossian poetry around 1760 was an occasion for both men to articulate the duality at its core. On one hand, the word was taken to refer to the behaviour, cultural practices and proclivities of humankind at a given point in time. In the case of Ossian, this was around the third century. On the other hand ‘manners’ referred to the poetic language within which these actions are described. Given the controversy over the historical authenticity of the Ossian poetry, it is not surprising that some noted a clear disjuncture between these two ideas: between the antiquity being depicted and the modernity of the poetic style. Blair, believing in the authenticity of Ossian as ancient epic poetry, sought to demonstrate that no such disjuncture existed. In the first meaning of the word, in which ‘manners’ designated behaviour and ritual, he understood the word to refer to whatever is susceptible to historical determination, progress and decline. By contrast, the poetic (and more specifically, prosodic) ‘manners’ of this verse, for Blair, a strongly ahistorical valence. This is because Blair maintains that the Ossian verse emerged from the earliest forms of primitive gestural communication, and that it therefore retains an immutable ‘perspicuity’ that is not susceptible to the vicissitudes of time.