• Consciousness
• Killing

Wade describes diagnostic and prognostic uncertainties encountered in trying to categorise patients with a prolonged disorder of consciousness (DOC). That DOCs are diagnostically controversial is well documented.1 Nonetheless, Wade's paper provides informative details and a neurologist's insights. But exactly what follows from difficulties in reliably diagnosing DOCs? Wade ‘concludes that this arises because consciousness forms a spectrum, so that no single test will ever define someone's state with certainty’. In other words, DOCs are impossible to diagnose because consciousness is a spectrum of awareness along which everyone is moving.

This is highly questionable. Although it is clearly true that ‘awareness … covers a range from heightened awareness to complete unresponsiveness’, it does not follow that everyone's level of awareness is in a constant state of flux. Colours form a spectrum, but it does not follow that everything is constantly changing colour. Likewise, the position on a spectrum of consciousness occupied by some DOC patients could now be fixed.

Not only is this possible, it is highly probable. For one thing, it is a priori feasible for a human brain to be malformed or damaged in such a way that consciousness is permanently either lacking or minimal. And there are real world instances: an anencephalic infant lacking a cerebrum and cerebellum does not have a fluctuating level of awareness; nor does a …