Post-Comatose Disorders of ConsciousnessAn important backdrop to the taxonomic developments in this field concerns a current
debate about how best to understand “global” states of consciousness. Many authors embrace a
level-based conception of global states, according to which alterations in an individual’s global
state of consciousness are to be understood in terms of changes in their level of consciousness
(e.g. Laureys 2005). Those who endorse this conception typically assume that VS patients have
a lower level of consciousness than MCS patients, and that MCS patients in turn have a lower
level of consciousness than patients who have returned to “full consciousness.” However, a num-
ber of authors have argued that this conception of global states of consciousness is problematic
(Bayne et al. 2016; Bayne and Hohwy 2016; Klein and Hohwy 2015). For one thing, genuine
VS patients (that is, patients who have sleep/wake cycles but no standing capacity for conscious-
ness) are completely unconscious, and thus it is misleading to describe them as possessing any
“level” of consciousness. Even when we restrict our attention to post-comatose patients who are
conscious, it is far from clear that talk of “levels of consciousness” is helpful. Although many of
the cognitive capacities that are associated with consciousness can be graded (for example, one
patient might be more responsive to perceptual stimulation than another), it is unclear whether
consciousness itself can be graded. To be conscious is to possess a subjective perspective, and that
is not a property that seems to admit of degrees.
Instead of assuming that all (conscious) post-comatose patients can be assigned to a single
“level of consciousness,” we think that a multidimensional approach to consciousness is more
likely to do justice to the variation exhibited by post-comatose patients (Bayne et al. 2016;
Sergent et al. 2017; Peterson and Bayne 2017). This approach promises to provide a more fine-
grained framework that captures the variation in cognitive and behavioral capacities exhibited
by post-comatose patients, without suggesting that this variation must correspond to variation
in degrees of consciousness. A key question, of course, concerns the nature of the dimensions
employed by any such taxonomy. We expect that this issue will be on the agenda of theorists in
this field for some time.
8 Ethical Dimensions of Post-Comatose
Disorders of ConsciousnessWe turn now to some of the many ethical issues raised by the findings that have been surveyed
in this chapter (Weijer et al. 2014; Fins et al. 2008). What implications might covert consciousness
have for the moral and legal protections that we should afford to post-comatose patients? In what
ways might it change the attitudes that medical professionals and family members ought to take
toward patients? Would the discovery of covert conscious give us a reason to provide a patient with
life-sustaining treatment, or might it instead give us a reason to withdraw life-sustaining treatment?
At the heart of these questions lie issues of moral status. A being has moral status if we owe
it moral consideration for its own sake. Violation of a being’s moral status results in harm to it. A
corpse has no moral status, for although there are moral (and indeed legal) constraints on what
can be done to a corpse, we do not owe a corpse moral consideration for its own sake—a corpse
cannot be harmed. You, by contrast, can be harmed, and are thus owed moral consideration for
your own sake.
What difference—if any—might the ascription of consciousness make to the moral status of
post-comatose patients? There is little doubt that the presence of consciousness should make a
difference to moral status, but there is debate about precisely what kind of difference it makes
and why it makes the difference it does.
Let us begin with what we regard as common ground in the literature: things matter to con-
scious patients in a way in which they don’t matter to unconscious patients. A conscious patient is