The ultimate Harvard committee-the ad hoc Committee on Death-has come under fire from philosophers and theologians.

The Committee, chaired by Henry K. Beeches, Dorr Professor of Anesthesiology Emeritus, was convened in 1968 to formulate a new definition of death to replace the classic Black's Law Dictionary (written in 1891) which says a person may be considered dead when he stops breathing and his heart stops beating.

The committee issued a report defining death as the point at which the brain stops functioning. A patient in irreversible coma could be considered dead under this definition, even though his heart and lungs were working fine.

In a paper presented to the annual meeting of the American Association for the Advancement of Science, in Chicago last month. Beeches said that some philosophers and theologians had termed his definition "callous," "unsavory," and "dangerous."

Crities say the definition would make it easier for doctors to give dying patients, in need of transplants, vital organs from patients who are alive under current laws, by pronouncing them in an irreversible coma. After the organs have been removed, of course, the patients would cease breathing and heart action would stop.

"We hope our definition will be adopted in legal practice," Beecher said yesterday. "Doctors have accepted it as an ethical definition."