sexism. Ryder stated in the pamphlet that "[s]ince Darwin, scientists have agreed that there is no 'magical' essential difference between humans and other animals, biologically-speaking. Why then do we make an almost total distinction morally? If all organisms are on one physical continuum, then we should also be on the same moral continuum." He wrote that, at that time in the United Kingdom, 5,000,000 animals were being used each year in experiments, and that attempting to gain benefits for our own species through the mistreatment of others was "just 'speciesism' and as such it is a selfish emotional argument rather than a reasoned one". Ryder used the term again in an essay, "Experiments on Animals", in Animals, Men and Morals (1971), a collection of essays on animal rights edited by philosophy graduate students Stanley and Roslind Godlovitch and John Harris, who were also members of the Oxford Group. Ryder wrote: In as much as both "race" and "species" are vague terms used in the classification of living creatures according, largely, to physical appearance, an analogy can be made between them. Discrimination on grounds of race, although most universally condoned two centuries ago, is now widely condemned. Similarly, it may come to pass that enlightened minds may one day abhor "speciesism" as much as they now detest "racism." The illogicality in both forms of prejudice is of an identical sort. If it is accepted as morally wrong to deliberately inflict suffering upon innocent human creatures, then it is only logical to also regard it as wrong to inflict suffering on innocent individuals of other species. ... The time has come to act upon this logic. Spread of the idea The term was popularized by the Australian philosopher Peter Singer in his book Animal Liberation (1975). Singer had known Ryder from his own time as a graduate philosophy student at Oxford. He credited Ryder with having coined the term and used it in the title of his book's fifth chapter: "Man's Dominion ... a short history of speciesism", defining it as "a prejudice or attitude of bias in favour of the interests of members of one's own species and against those of members of other species": Racists violate the principle of equality by giving greater weight to the interests of members of their own race when there is a clash between their interests and the interests of those of another race. Sexists