Mystical and spiritual experiences have been reported throughout human history. Causal explanations for these range from psychopathology of mental illness, drugs such as hallucinogens, neurological disorders including temporal lobe epilepsy, and genuine mystical or spiritual awakening. There is a common core of phenomena in such experiences, as described both in historical accounts and recent research, but also evidence of cultural specificity. This article is a personal account of such an experience, which occurred in a postanesthetic state. A striking feature of the experience was noesis: a sense of revelation and complete understanding. I argue that while there must be a neural basis to these phenomena, it is difficult to reduce the subjective meaning of the experience purely to a brain dysfunction. Reconciling mechanism and meaning of such experiences remains a challenge for both neuroscience and philosophy.