 According to Bulkeley, "Newberg and D'Aquili seem blissfully unaware of the past half century of critical scholarship questioning universalistic claims about human nature and experience".Matthew Day also notes that the discovery of a neurological substrate of a "religious experience" is an isolated finding which "doesn't even come close to a robust theory of religion".Recent studies evidenced the relevance of the default mode network in spiritual and self-transcending experiences.