Laughter … is a reflex that characterises man alone and has its own history … We do not laugh now as people once laughed … a definition [of the comic and of laughter] can be only historical.
Men have been wise in many different modes, but they have always laughed the same way.
NATURE AND CULTURE, BODIES AND MINDS
When ancient Greeks laughed, did they take themselves to be yielding to an instinct rooted in their animal bodies or displaying a characteristic they shared with their gods? Might they have imagined, for that matter, that they were doing both those things at the same time?
In broaching such large, scene-setting questions, it is hard to avoid taking initial orientation from Aristotle's famous obiter dictum in the Parts of Animals that humans are the only living things capable of laughter. This proposition – sometimes replaced in antiquity, and even conflated (as it occasionally still is), with the logically distinct idea of laughter as part of the essence of humans – addresses an issue which has continued to provoke debate right up to the contemporary study of animal behaviour. It would be unreasonable to expect Aristotle, for all his wide-ranging biological interests, to have anticipated the findings of the modern science of ethology, which claims to identify among other primates (and possibly elsewhere too) forms of behaviour that are physically and even socially analogous to laughter (and smiling) and that can help shed light on the evolution of these types of body language among humans.