So why don't we make ourselves the last generation on earth? If we would all agree to have ourselves sterilized then no sacrifices would be required - we could party our way into extinction!

...the proposed air force and army experiments were designed so that many animals would suffer and die without any certainty that this suffering and death would save a single human life or benefit humans in any way at all; but the same can be said of millions of their experiments performed each year in the United States alone.

In appropriate circumstances we are justified in using humans to achieve goals (or the goal of assisting animals).

For most humans, especially for those in modern urban and suburban communities, the most direct form of contact with nonhuman animals is at meal time: we eat them.... The use and abuse of animals raised for food far exceeds, in sheer numbers of animals affected, any other kind of mistreatment.

Surely there will be some nonhuman animals whose lives, by any standards, are more valuable than the lives of some humans.

Sometimes we know the best thing to do, but fail to do it. New year's resolutions are often like that. We make resolutions because we know it would be better for us to lose weight, or get fit, or spend more time with our children. The problem is that a resolution is generally easier to break than it is to keep.

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.