Dr. Christian Barnard, the doctor who performed the first human heart transplant, said, "The principal aim of medicine is to alleviate suffering, not to prolong life. When medicine extends life that has ceased to have meaning for the patient, it is evil.  My concept of medicine is for doctors to give their patients a good life, and death is a part of life.  If we cannot give them life, let us give them a good death."

Whatever else Dr. Barnard meant, he put his finger on a significant truth.  The real enemy of life is not aging.  The real enemy of life is not even death.  The real enemy is not really being alive while you live. The important thing is the quality of life that we have.