In 1990, Terri Schiavo suffered a heart attack and fell into a coma. According to her doctors she was in a vegetative state without any possibility of recovery. Her husband wanted her feeding tube removed, so she could be allowed to die, but her parents believed she was still conscious. Their legal battle wound through the courts for years, becoming a media sensation. At one point, President George W. Bush signed a legislative bill specifically to keep her feeding tube in place. The drama ended only when a federal appeals court finally ordered her feeding tube removed. She died in 2005 after fifteen years in a coma.
The autopsy showed that her brain was severely damaged. Among other notable changes, nearly all her cortical pyramidal neurons were gone. Pyramidal neurons are the brain’s long-distance communicators. Without them there is no possibility of a functioning network, and no possibility of anything we would consider human thought.
To me, the Terri Schiavo case shows the powerful tendency of humans to attribute consciousness to each other.
Philosophers sometimes amuse themselves with an intellectual puzzle: I know I’m conscious, but can I ever really know whether someone or something else is conscious? One popular approach is the Turing test, where you talk to an entity and try to figure out whether it’s a machine or a person. But the Turing test doesn’t apply to a case like Terri Schiavo’s, because she couldn’t talk. The Turing test represents intellectual deduction based on evidence, whereas in Terri’s case something more fundamental and emotional was going on. Her parents experienced a gut wrenching, raw perception—they knew she was conscious. They felt her presence in the room when they sat next to her. In trying to explain their certainty to others they sometimes resorted to rationalizations, for example pointing out the subtle movements of her eyes. The doctors offered alternative explanations: Low-level, brainstem circuits must be triggering the occasional random movements. Schiavo’s parents were unimpressed.