A clinical diagnosis of Aedh’s erotic and other visions would doubtless have concluded that , whatever shaped them in his psyche, they were triggered by his reckless fasting. Hallucination as a result of extreme exhaustion, including that which has resulted from semi-starvation, is a well-established condition, though many more centuries would pass after Aedh’s time before this was recognised. But visionaries of every father at all stages of history have tended to be people whose lives are marked by exceptional austerity, and it is difficult to think of a single instance in which a holy man or woman has reported tempting, fearsome or inspiring manifestations, on a regime of ample food and sleep.
On one level there is nothing objectionable about the above. Moorhouse, whose book I greatly admire, is careful not the ascribed the visions to starvation per se, but as a triggering factor. I I am suspicious of retrospective diagnosis and also of transporting the clinical worldview outside its natural habitat But reading this passage, a brief thought occurs. For the vast majority of the time homo sapiens has been in existence “ample food and sleep” have not been the common condition of humanity. Indeed, a regime of ample food and sleep could be said to be as anomalous as complex societies themselves- as Tainter points out