Can we avoid assigning greater value to some human lives than to others?

Each and every human life, is equally sacred or is of infinite worth or of infinite intrinsic value. To regard the life of a severely and irreparably retarded human being as less valuable than the life of a normal human, those who take this position will suggest, is to violate this fundamental notion of human equality. Capacities to reason, to anticipate the distant future, to communicate in a sophisticated way, to plan their lives, to be as fully self-conscious as humans are: all these things one might say, mark off the normal mature human from most if not all other species. The basic principle being discussed, the principle of the sanctity of life, is being eroded by greater critical reflection outside the religious framework in which it most naturally fits. To regard the life of a severely and irreparably retarded human being as less valuable than the life of a normal human.