If possessing a higher degree of intelligence does not entitle one human to use another for his or her own ends, how can it entitle humans to exploit non-humans?

When children see animals in a circus, they learn that animals exist for our amusement. Quite apart from the cruelty involved in training and confining these animals, the whole idea that we should enjoy the humiliating spectacle of an elephant or lion made to perform circus tricks shows a lack of respect for the animals as individuals.

The newspapers do little better. Their coverage of nonhuman animals is dominated by "human interest" events like the birth of a baby gorilla at the zoo, or by threats to endangered species; but developments in farming techniques that deprive millions of animals of freedom of movement go unreported.

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

If we all think only of our own interests, we are headed for collective disaster - just look at what we are doing to our planet's climate.

Once we ask why it should be that all human beings - including infants, the intellectually disabled, criminal psychopaths, Hitler, Stalin, and the rest - have some kind of dignity or worth that no elephant, pig, or chimpanzee can ever achieve, we see that this question is as difficult to answer as our original request for some relevant fact that justifies the inequality of humans and other animals.

Capitalism is very far from a perfect system, but so far we have yet to find anything that clearly does a better job of meeting human needs than a regulated capitalist economy coupled with a welfare and health care system that meets the basic needs of those who do not thrive in the capitalist economy. If we ever do find a better system, I'll be happy to call myself an anti-capitalist.