Philosopher Hilary Putnam famously proposed a thought experiment in which you are actually a brain nestled in a vat that has been hooked up by an evil scientist to a computer that perfectly simulates the experiences of the outside world. How can you tell that you are not, in fact, a brain in a vat?
Researchers at Yale University have taken a step toward making something like that thought experiment possible by successfully reviving some of the biological functions of brains from pigs slaughtered hours earlier. The researchers achieved this milestone by pumping into these dead pig brains their BrainEx formula, "a hemoglobin-based, acellular, non-coagulative, echogenic, and cytoprotective perfusate that promotes recovery from anoxia, reduces reperfusion injury, prevents edema, and metabolically supports the energy requirements of the brain."
It has long been medical dogma that brain cells cut off from oxygen die within minutes. In this case, revived brain cells began metabolizing again. This research raises two ethical issues: (1) how might this effect organ donation, and (2) should we worry about disembodied pig consciousness?
In 1968, a committee of ethicists and physicians convened at Harvard to define brain death as irreversible coma in which patients have no discernible central nervous system activity. The organs of such brain dead individuals could be harvested for transplantation into other patients. But what if something like BrainEx could, in the future, revive the brains of folks who heretofore have been declared brain dead? That might well reduce the number of potential organ donors from the 10,000 or so whose organs are harvested every year in the United States.
What about pig consciousness? Regulations that cover animal experimentation do not apply to dead animals. Nevertheless, the Yale researchers dosed their BrainEx with chemicals to block neural activity in the pigs' brains to try to ensure they never became conscious. They were also ready to administer anesthesia if the brains exhibited any electrical activity that would suggest communication between the revived neurons. No signs of porcine consciousness were detected.
What would a "conscious" pig brain in a vat experience? Likely not pain, since brains do not have pain receptors. If a brain is receiving no outside sensory information, would that induce terror or satori?
One other implication of this research is that improved versions of BrainEx could make possible whole body transplants of the sort being proposed by Italian neurosurgeon Sergio Canavero.