[...] even if we were to prevent the infliction of suffering on animals only when the interests of humans will not be affected to anything like the extent that animals are affected, we would be forced to make radical changes in our treatment of animals that would involve our diet, the farming methods we use, experimental procedures in many fields of science, our approach to wildlife and to hunting, trapping and the wearing of furs, and areas of entertainment like circuses, rodeos, and zoos. As a result, the total quantity of suffering caused would be greatly reduced; so greatly that it is hard to imagine any other change of moral attitude that would cause so great a reduction in the total sum of suffering in the universe.

Arguments for preservation based on the beauty of wilderness are sometimes treated as if they were of little weight because they are 'merely aesthetic'. That is a mistake. We go to great lenghts to preserve the artistic treasures of earlier human civilistations. It is difficult to imagine any economic gain that we would be prepared to accept as adequate compensation for, for instance, the destruction of the paintings in the Louvre. How should we compare the aesthetic value of wilderness with that of the paintings of the Louvre? Here, perhaps, judgment does become inescapably subjective; so I shall report my own experiences. I have looked at the paintings in the Louvre, and in many of the other great galleries of Europe and the United States. I think I have a reasonable sense of appreciation of the fine arts; yet I have not had, in any museum, experiences that filled my aesthetic senses in the way that they are filled when I walk in a natural setting and pause to survey the view from a rocky peak overlooking a forested valley, or sit by a stream tumbling over moss-covered boulders set amongst tall tree-ferns, growing in the shade of the forest canopy. I do not think I am alone in this; for many people, wilderness is the source of the greatest feelings of aesthetic appreciation, rising to an almost spiritual intensity.