We tested and validated the German version of a new instrument for measuring "wakefulness," defined as "an expansive, higher-functioning, and stable state of being in which a person's vision of and relationship to the world are transformed, along with their subjective experience, their sense of identity and their conceptual outlook" (Taylor, 2017, p. 22). In order to test the construct validity of the new instrument (Inventory of Secular/Spiritual Wakefulness; WAKE-16), we performed a parametric comparison between a group of expert meditators (n=36) with a history of predominantly meditating in silence and demographically matched non-meditators (n=36) for the WAKE-16 and two conceptually related questionnaires of mindfulness and emotion regulation. Significantly higher scores for the meditators on the WAKE-16 indicate construct validity of the new instrument. Meditators scored higher on the two mindfulness subscales "presence" and "acceptance," as well as on the SEE subscales of emotion regulation and body-related symbolization of emotions. Within the group of meditators, there were significant correlations between wakefulness and mindfulness, accepting one's own emotions, and experiencing overwhelming emotions. The only significant correlation in non-meditators was found between wakefulness and accepting one's own emotions. The new instrument shows construct validity by discriminating between the two groups. Correlations between wakefulness and related psychological constructs indicate convergent validity. Future studies could attempt to increase discriminatory accuracy of the definition of wakefulness, as well as finding objective methods of measuring.