Even those sceptical about supernatural and transcendent realms should take seriously the possibility of psychedelic-assisted knowledge gain. I have suggested that psychedelics may afford the gaining of factual knowledge (of one's own mind, others' minds, abstract patterns in one's life, and novel solutions to specialist problems); of ability knowledge (especially knowledge how to let go and accept inner experience); and of greater understanding via new modes of presentation. I have also offered some suggestions about how to test these hypotheses. The epistemic claims of psychedelic subjects should not be accepted uncritically, but nor can they be refuted from the armchair. Specific proposals about psychedelic epistemology must be considered in their own right and subjected to rigorous interdisciplinary inquiry. Mounting evidence for the therapeutic efficacy of psychedelics behoves us urgently to understand the mechanisms of this strikingly novel treatment modality. One pressing question is whether it is a form of therapy based on genuine insight. I think it probably is — but only further research will tell. Most generally, we need to appreciate that there is a viable third way between traditional conceptions of psychedelics as entheogens disclosing transcendent supernatural realms, and as hallucinogens or psychotomimetics whose epistemic effects are solely detrimental.