As neuroscience gives us new abilities to do what we never dreamed possible, it also creates profound challenges in ethics and law. When we cannot do something, there is little or no point in asking whether we should do it. But when neuroscience (or any other science) makes it possible to do something novel, then we need to ask whether, when, why, and how we should exercise this ability. One recent example of this trend is the ability to detect consciousness in patients who have suffered severe brain damage and show no outward sign of consciousness. In the past, families and doctors never imagined that they could communicate with these patients. Then, in 2006, a groundbreaking paper showed that an original method could be used to detect consciousness in patients who had previously been thought unconscious and unreachable. A follow-up paper in 2010 showed that such patients could even answer questions. One patient who had shown no outward sign of consciousness for 5 years answered five autobiographical questions correctly by thinking of motor imagery for “Yes” and spatial imagery for “No.” The answers could be detected by brain scanning, although it was impossible to communicate with the patient in any other way. These findings surprised and confused many readers. The first confusion concerns the precise condition of these patients. We need to distinguish persistent and permanent vegetative states from death, coma, minimally conscious states, and locked-in syndrome. We also need to ask whether consciousness has been or is likely to be found in patients whose current condition is a result of anoxia, brain disease, or traumatic brain injury. The proper diagnosis of these conditions is a complex and uncertain medical issue.