The nineteenth-century French painter Gustave Courbet famously declared that he did not paint angels because he had never seen one. If artists of classical antiquity were ever troubled by such scruples regarding depictions of the supernatural, it is not (so far as I know) documented. This is not to say that the question of how an artist could represent, say, an Olympian deity, went completely unheeded: Dio Chrysostom's Olympic Discourse of ad 97 is one serious attempt to address that topic, with significant implications for the status of an artist (in this case, Pheidias) famed for ‘imagining’ the divine. Yet evidently the task of visualizing spiritual phenomena devolved no less to humble ‘craftsmen’ – as Hélène Collard shows in her monograph, Montrer l'invisible. This gathers a catalogue of 164 Athenian vases, mostly of the fifth-century bc, as case studies of the various formulations devised to show religious experience – many of them images upon objects, such as white-ground lekythoi, that may once have been used in particular rites and observances. Graphic traditions of mythology, and an established series of personification (e.g. Nike, Eros, Hypnos), assisted the process. However, many of the scenes collected by Collard do not apparently attempt to ‘show the invisible’. They seem, rather, to evoke the realities of regular practice – processions, libations, sacrifice, adornment of a stele. Such scenes only become ‘paranormal’ when invested with some extra knowing detail: for example, a large owl alighting upon an altar (presumably indicating the favour of Athena). And sometimes we simply have to look a little closer to apprehend the signs of divine agency. So a herm-head appears to lean forwards – as if to sip at the kantharos held up in propitiation – while the phallus of another herm seems distinctly to elongate in the presence of two ecstatic women.