"An altered state of consciousness (ASC) may be defined as a temporary change in the overall pattern of subjective experience, such that the individual believes that his or her mental functioning is distinctly different from certain general norms for his or her normal waking state of consciousness". Farthing (1992, p. 205) He lists fourteen dimensions of changed subjective experience. To account for an ASC, multiple dimensions need to be altered. A recent working definition for empirical research is based on these previous definitions and provided by Schmidt. [Translated from German]: As a working definition for neuroscientific research, it might suffice to presume that most people have a strong intuition concerning which variability in their everyday wakeful state feels normal to them. This variability of experience is considered as normal fluctuation, while any state that is experienced to diverge significantly from it can be called an ASC. From an experimental perspective, it is also reasonable to compare ASC conditions to a baseline state – a state subjectively judged as average, or normal. The comparison with a 'normal' baseline requires that the ASC under investigation is of relatively short duration (minutes to hours), which differentiates ASCs from most pathological conditions. Importantly, it has been emphasized that an ASC is not a mere quantitative change in a single cognitive function (e.g. elevated arousal). Instead, it is a multidimensional phenomenon. Thereby, the relative intensity of multiple consciousness aspects constitutes a 'phenomenological pattern' characterizing a particular state. Such 'patterns' have also been referred to as relative changes in the '(basic) dimensions of consciousness'. For empirical research, such patterns correspond to a multivariate combination of independent 'consciousness factors', which can be quantified via questionnaires. The 'phenomenological pattern' results from the factor structure of the applied psychometric assessment, i.e. the individual ratings, or factor scores, of a questionnaire. History History of utilization of ASCs Altered states of consciousness might have been employed by humans as early as 30,000 years ago. Mind-altering plants and/or excessive dancing were used to attain an ecstatic or mystic state. Examples of early religious use of altered states of consciousness are the rites of Dionysos and the Eleusinian Mysteries, as well as yoga and meditation. Followers of various shamanic traditions "enter altered states of consciousness in order to serve their community." Terence McKenna has suggested that the use of psychedelic mushrooms in prehistoric times has led to the "evolution of human language and