Lately, nonhuman animals have been the topic of a great deal of social and professional discussion. Open questions concern animals' moral status as well as their mental lives. On the moral front, the animal protection movement in the past quarter-century has questioned traditional assumptions about animals—that they have little or no moral status, and that they may be used for practically any human purpose. But some have taken this movement to deny obvious moral differences between humans and animals. Spokespersons for professions that use animals have sometimes angrily asserted a fundamental, unquestionable gulf between humans and other animals. Who is right? How are we to understand the moral status of animals? Among the obvious differences between humans and animals, which, if any, are morally important? We have nothing resembling a consensus on these issues.

The jury is also out with respect to animal minds. As the scientific study of animal mentation gains respectability, the public is increasingly fascinated by this topic. Note the popular books speculating about waking and dreaming states of various domestic species (not to mention television commercials featuring cute animals drinking beer or driving trucks). While some see the increased attention to animal minds as hopelessly sentimental anthropomorphism, others take it to reflect the overdue demise of a prejudice against animals.

While intriguing and important in its own right, the mental life of animals is also crucial to the ethical study of animals—animal ethics, as it is now called.