Date of Award


Document Type




First Advisor

Josh Fost


Consciousness, Neuropsychology, Anesthesia




Consciousness is difficult to pin down. Most human beings go about their days with full and more or less uninterrupted consciousness, without contemplating their own (or other peoples’) conscious states. To be in the world, and accomplish great acts takes little metaawareness of consciousness, but in the study of consciousness our inability to think outside of our conscious states creates controversies at the conceptual and methodological levels. As Victor Lamme states (2006), even when we set aside the more difficult (or more poorly defined) questions about conscious experience to focus on finding the neural correlates of consciousness (NCC), we face immense difficulties (Lamme, 2006, p. 494). Experiments designed to find the NCC often involve the manipulation of conscious states through anesthesia, the study of sleep, or brain lesion studies (Lamme, 2006, p. 494). However, even in the case of anesthesia, where we can voluntarily induce a reversible altered state of consciousness there does not seem to be a clear dividing line between consciousness and unconsciousness with any of the processed electroencephalogram (EEG) signals (Guzeldere, 1998, p. 1) such that the conscious and unconscious states are still confirmed behaviorally (Lamme, 2006, p. 494). This leads to a problem, as it must be decided what "behavioral measures 'count' as evidence for the subject having conscious experience (p. 494)" a problem that is not so simple as the ability to speak and respond, as will be more clear in a later discussion of intraoperative awareness. Furthermore, Guven Guzeldere points to the difficulty of defining what "the problem of consciousness" is, within and "across disciplinary boundaries (Guzeldere, p. 7)." The problems that philosophers of consciousness, cognitive scientists and neuroscientists address when they study consciousness are not inevitably going to be identical, but are shaped by disciplinary perspectives, methods and technologies.

Therefore, in this paper I am going to contrast two similar models of consciousness, Giulio Tononi’s Integrated Information Theory and Daniel Dennett’s Multiple Drafts Model, and evaluate them against the mechanisms of several anesthetics (Propofol, ketamine, and the inhalation anesthetics, including xenon), which will be summarized by a review of the literature. I have two goals in mind with this project: first, I have chosen two very similar models in order to demonstrate how small differences- such as Tononi’s engagement with the concept of qualia and Dennett’s deconstruction of it-- have large implications for what types of knowledge are possible when these models are applied; second, I am summarizing the literature concerning the study of anesthetics to show both that anesthetics are useful for the elucidation of the neural correlates of consciousness, and that there is a danger of conflating the neural correlates of unconsciousness with a full description of how consciousness arises, or what consciousness is. Moreover, I will argue that because Dennett’s model specifically addresses the importance of language in shaping human consciousness, despite the distance between his model and a full neurobiological approach, his model is more useful going forward. It must be emphasized that I am not arguing that Dennett’s model is the correct model of consciousness, but that he is thinking about consciousness in the right ways.


An undergraduate honors thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in University Honors and Chemistry

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