Quite a few recent models are rapidly introducing new concepts describing different levels of consciousness. This situation is getting confusing because some theorists formulate their models without making reference to existing views, redundantly adding complexity to an already difficult problem. In this paper, I present and compare nine neurocognitive models to highlight points of convergence and divergence. Two aspects of consciousness seem especially important: perception of self in time and complexity of self-representations. To this I add frequency of self-focus, amount (...) of self-related information, and accuracy of self-knowledge. Overall, I conclude that many novel concepts (e.g., reflective, primary, core, extended, recursive, and minimal consciousness) are useful in helping us distinguish between delicate variations in consciousness and in clarifying theoretical issues that have been intensely debated in the scientific literature—e.g., consciousness in relation to mirror self-recognition and language. Ó 2005 Elsevier Inc. All rights reserved. (shrink)

Within theoretical and empirical enquiries, many different meanings associated with consciousness have appeared, leaving the term itself quite vague. This makes formulating an abstract and unifying version of the concept of consciousness – the main aim of this article –into an urgent theoretical imperative. It is argued that consciousness, characterized as dually accessible (cognized from the inside and the outside), hierarchically referential (semantically ordered), bodily determined (embedded in the working structures of an organism or conscious system), and useful in action (...) (pragmatically functional), is a graded rather than an all-or-none phenomenon. A gradational approach, however, despite its explanatory advantages, can lead to some counterintuitive consequences and theoretical problems. In most such conceptions consciousness is extended globally (attached to primitive organisms or artificial systems), but also locally (connected to certain lower-level neuronal and bodily processes). For example, according to information integration theory (as introduced recently by Tononi and Koch, 2014), even such simple artificial systems as photodiodes possess miniscule amounts of consciousness. The major challenge for this article, then, is to establish reasonable, empirically justified constraints on how extended the range of a graded consciousness could be. It is argued that conscious systems are limited globally by the ability to individuate information (where individuated information is understood as evolutionarily embedded, socially altered, and private), whereas local limitations should be determined on the basis of a hypothesis about the action-oriented nature of the processes that select states of consciousness. Using these constraints, an abstract concept of consciousness is arrived at, hopefully contributing to a more unified state of play within consciousness studies itself. (shrink)

This paper argues that the many and various conceptions of consciousness propounded by cognitive scientists and philosophers can all be understood as constituted with reference to four fundamental sorts of criterion: epistemic (concerned with kinds of consciousness), semantic (dealing with orders of consciousness), physiological (reflecting states of consciousness), and pragmatic (seeking to capture types of consciousness). The resulting four-fold taxonomy, intended to be exhaustive, suggests that all of the distinct varieties of consciousness currently encountered in cognitive neuroscience, the philosophy of (...) mind, clinical psychology, and other related fields ultimately refer to a unified natural process, analysed under four general aspects. The proposed taxonomy will, it is hoped, possess sufficient clarity to serve as a sound theoretical framework for further scientific studies, and to count as a significant step in the direction of a properly formulated unified concept of consciousness. (shrink)