Sometimes animals may suffer more because of their more limited understanding. If, for instance, we are taking prisoners in wartime we can explain to them that although they must submit to capture, search, and confinement, they will not otherwise be harmed and will be set free at the conclusion of hostilities. If we capture wild animals, however, we cannot explain that we are not threatening their lives. A wild animal cannot distinguish an attempt to overpower and confine from an attempt to kill; the one causes as much terror as the other.

It is easy for us to criticize the prejudices of our grandfathers, from which our fathers freed themselves. It is more difficult to distance ourselves from our own views, so that we can dispassionately search for prejudices among the beliefs and values we hold

To give preference to the life of a being simply because that being is a member of our species would put us in the same position as racists who give preference to those who are members of their race.

Pain is pain, and the importance of preventing unnecessary pain and suffering does not diminish because the being that suffers is not a member of our own species.

The traditional view of the sanctity of human life will collapse under pressure from scientific, technological and demographic developments.

To turn the other cheek is to teach would-be cheats that cheating pays.

What one generation finds ridiculous, the next accepts; and the third shudders when it looks back on what the first did.