Abstract

Altered states of consciousness (ASC), especially hallucinatory ones, are philosophically and scientifically interesting modes of operation of the mind–brain complex. However, classical definitions of ASC seem to capture only a few common characteristics of traditionally regarded phenomena, thus lacking exact classification criteria for assessing altered and baseline states. The current situation leads to a priority problem between phenomena-based definitions and definition-based phenomena selection. In order to solve the problem, this paper introduces a self-mapping procedure that is based on a three-part analysis on certain aspects of hallucinatory altered consciousness. Starting with commonalities found in current definitions of ASC, issues with self-evaluation, sources of data, and baseline comparison are analyzed first. Next, the concept of alterations is examined with respect to temporal dynamics, change mechanisms, and mental subsystems. Finally, hallucinatory phenomena are discussed regarding various definitions, the relationship between “external” and “internal,” and the “trueness” issue of hallucinations. Conclusive to the analysis above, a technically based working definition of ASC and a stepwise operationalization procedure are also proposed.