To the man who is truly ethical all life is sacred, including that which from the human point of view seems lower in the scale. He makes distinctions only as each case comes before him, and under the pressure of necessity, as, for example, when it falls to him to decide which of two lives he must sacrifice in order to preserve the other. But all through this series of decisions he is conscious of acting on subjective grounds and arbitrarily, and knows that he bears the responsibility for the life which is sacrificed.
Albert Schweitzer, Charles Rhind Joy (1947). “Albert Schweitzer: An Anthology”, Boston : Beacon Press