Jason Castro in Aeon:
What is the distance between the scent of a rose and the odour of camphor? Are floral smells perpendicular to smoky ones? Is the geometry of ‘odour space’ Euclidean, following the rules about lines, shapes and angles that decorate countless high-school chalkboards? To many, these will seem like either unserious questions or, less charitably, meaningless ones. Geometry is logic made visible, after all; the business of drawing unassailable conclusions from clearly stated axioms. And odour is, let’s be honest, a bit too vague and vaporous for any of that. The folksy idea of smell as the blunted and structureless sense is at least as old as Plato, and I have to confess that, even as an olfactory researcher, I sometimes feel like I’m studying the Pluto of the sensory systems – a shadowy, out-there iceball on a weird orbit.
In recent years, however, things have changed dramatically, and understanding what one might call ‘the geometry of smell’ is a field that now enlists task forces of neuroscientists working together with mathematically trained theorists and artificial intelligence (AI) experts.
More here.