‘Expression’ is less a self-explanatory concept today than a placeholder for a gaping uncertainty. Used as shorthand for the appearance of an ‘inner life’, the term ‘expression’ demarcates a vague terrain where aesthetic form and psychological feeling are inextricably, even unsettlingly entangled. Understanding expression in fact demands a complex triangulation of knowledge between aesthetics, psychology and biology. As a mediating concept between the natural and artificial, it raises important questions about nature’s own aesthetic manifestations. For nature, too, produces ‘images’. Does it, then, ‘express’ itself? To what degree can expression be understood as a sign of life, or a trace of mind? How do atmospheres, landscapes, animal, vegetal, mineral life strike the human viewer as ‘expressive’, and why? What would an expressivity without a subject, intentionality or interiority look like?