February 20, 2017
What is consciousness, and what is a good measure of it? Grinnell College philosopher Joseph Neisser sought to approach this issue from a scientific lens in a CMBC lunch discussion. Dr. Neisser traced the history of thinking about consciousness, introduced Integrated Information Theory as a new attempt to address the problem of measuring consciousness, and discussed limitations and future directions of this line of research.
Consciousness has been studied from a variety of perspectives and disciplines. Philosophical and psychoanalytic perspectives that attempt to account for a first-person perspective of consciousness lack quantitative measures of consciousness, because introspection is an unreliable and difficult-to-measure variable. Dr. Neisser outlined an empirical stance towards consciousness, which aims to coordinate a theory of consciousness with current data models of neural activity without making experiential, a-priori, and/or moral claims about consciousness.
What Dr. Neisser describes as the general theory of consciousness called Phi (ɸ) attempts to account for this problem by defining consciousness as a system of dynamic complexity and neural integration. This perspective, developed by mathematicians, allows scholars to measure the degree of consciousness of a system quantitatively from an objective third-person stance. Proponents of the theory of phi have used it to assess degree of consciousness in coma and related states, such as deep sleep, patients under anesthesia, and individuals in permanent vegetative states (PVS).
This research is important to clinicians and patients because individuals diagnosed with PVS vary in their levels of consciousness. Phi can quantitatively assess degrees of consciousness in these patients. Neural responses to transcranial magnetic stimulation in these patients can assist doctors in making a determination on whether to keep these patients alive, as some patients may have more functional integration of various brain systems than others, completely independent of their behavior or responsiveness to stimuli.
A community of scholars in psychology, neuroscience, and the humanities enjoyed a fruitful discussion on the many questions this position on consciousness raised. Does phi measure level of arousal of a subject, rather than consciousness itself, and is this distinction important? Some attendees argued that this theory is necessary but not sufficient to understanding consciousness, as responsive neural networks may not be equivalent to the phenomenological experience of having sensory experiences in the world.
Given that this approach is such a departure from our historical and lay perspectives on what consciousness is, what about the content of consciousness? Do first-person perspectives, subjectivity, narrative, and knowledge play a role? Some philosophers, such as John Searle, argue that these are essential attributes of human consciousness. Proponents of phi and empirical studies of consciousness think that our intuitions about consciousness erroneously define what its attributes are. They believe that the content of what people experience from a first person experience is less relevant than how coordinated or integrated the brain is in processing the experience.
I am especially interested in thinking about the moral ramifications of this work on PVS patients. Bioethics is an emerging field that engages discussion on contemporary medical issues such as genome editing, disease containment, and right to life. On one hand, it can be argued that there is a moral imperative to help apparently vegetative patients that are discovered to be minimally conscious. However, clinicians also must consider other challenges such as cost of care and perspectives of family members when making these determinations— no easy feat. It is important for scholars making empirical claims in their research not to lose sight of the human impact of their work.
See the discussion handout created by Dr. Neisser here: Consciousness from an Empirical Stance