The proposed analysis should not make use of any term that is just as obscure in meaning as the term being analyzed. JFK died in 1963. The last dodo bird died in 1681. Feldman's apple tree died in 1986. P is dead if and only if P's entire brain has permanently ceased functioning.
P is dead if and only P's cerebral cortex has permanently ceased funtioning.
The respirator is invented and perfected. The Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death publishes its report in the Journal of the American Medical Association. What did and didn't follow. Given technological developments, C2 is now the most accurate way of determining whether the traditional criterion is met. C2 is an indicator of the cessation of systemic functioning which is also what C1 is suppose to be an indicator of.