Transformative experiences have long been a central interest for anthropologists studying spiritual phenomena. During fieldwork, many ethnographers have themselves undergone such experiences, caused by and fueling their confidence in radical participation as the soundest approach to understanding spiritual phenomena. These anthropologists inadvertently find themselves faced with the question of the ontological status of such phenomena, responses to which range from embracing them as ontologically real to steering clear of judgment. Arguments pertaining to the authority of the anthropologist follow a similar path, belief either framed as a precondition for understanding such matters or as undermining analytical validity. This article outlines the third position. Based on radically engaged fieldwork conducted with people dedicated to spiritual and mindfulnessmeditation training in Denmark, I explore doubt as a transformative experience. Doubt, I hold, destabilizes both ontological certainty and the alleged analytical invalidity of engaged anthropology, making doubt, I argue, a valuable anthropological disposition. [Denmark mindfulness-meditation epistemologyand methodology] Danish abstract Transformerende oplevelser har laenge vaeret et centralt emne for antropologer, der studerer spirituelle faenomener. Som radikalt-deltagende oplever mange af disse antropologer selv at blive transformeret i løbet af feltarbejdet, hvilket forstaerker deres vurdering af radikal-deltagelse som den mest egnede måde at undersøge spirituelle faenomener på. Samtidig rejser oplevelserne spørgsmålet om spirituelle faenomeners ontologiske status, og her deler vandene sig mellem dem, der omfavner faenomenerne som ontologiske sandheder, og dem, der afviger fra at afgive vurdering. Denne splittelse forplantes ligeledes i diskussioner om antropologisk autoritet, hvor tro enten ses som afgørende for at forstå spirituelle faenomener eller som underminerende for analytisk validitet. Denne artikel skitserer en tredje position. Baseret på radikalt-deltagende feltarbejde blandt mennesker i Danmark, som er dedikerede til spirituel og mindfulness-meditations traening, udforsker jeg tvivl som en transformerende oplevelse, der destabiliserer både ontologisk vished og den angivelige analytiske invaliditet, og argumenterer for tvivl som vaerende en vaerdifuld antropologisk disposition."Spirituality. I have no sensory experience of it." The words were Karen's. We were in the car, Karen, Camille, and I, talking about meditation, mindfulness, and, yes, spirituality. It was September 2017, and this was the first of many long conversations, in this car, together, on our way to our mindfulness and meditation training. We were in it together, but rather differently: Camille with a Catholic upbringing and childhood experiences of sensing malevolent spirits; Karen with a mother who throughout Karen's childhood was engaged in meditative practices, and a sister who showed signs of possessing "special abilities" from an early age; and me with parents who were politic...