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?

Somebody who eats twice as much factory-farmed products as he or she needs to is clearly doing twice as much damage to the planet. From a utilitarian point of view, that's twice as bad.

When the death of a disabled infant will lead to the birth of another infant with better prospects of a happy life, the total amount of happiness will be greater if the disabled infant is killed. The loss of happy life for the first infant is outweighed by the gain of happier life for the second. Therefore, if killing the hemophiliac infant has no adverse effect on others, it would, according to the total view, be right to kill him.

If penicillin had been judged by its toxicity to guinea pigs, it might never have been used by man.

Habits of thought lead us to brush aside descriptions of cruelty to animals as emotional, for "animal-lovers only"; or if not that, then anyway the problem is so trivial in comparison to the problems of human beings that no sensible person could give it time and attention. This too is a prejudice - for how can one know that a problem is trivial until one has taken the time to examine its extent?

Do business managers have a commitment to anything more than the success of their company and to making money? It would be hard to say that they do. Indeed, many business leaders deny that there is any conflict between self-interest and the interests of all.

Forests and meat animals compete for the same land. The prodigious appetite of the affluent nations for meat means that agribusiness can pay more than those who want to preserve or restore the forest. We are, quite literally, gambling with the future of our planet – for the sake of hamburgers