Anthropologist: It has been claimed that religious prohibitions against eating certain types of food are evidence against the belief that all cultural phenomena have a purely economic explanation. After all, the reasoning goes, only a moral or spiritual motive could persuade people to forgo readily available sources of nutrients. But the species whose consumption is prohibited are usually essential elements of ecosystems containing other species that are used as food. The preservation of the prohibited species thus tends to help preserve the other species. Ttherefore, such prohibitions do indeed have an economic motivation. The reasoning in the anthropologist's argument is flawed because the argument ['takes for granted that people could have a reason for adopting a certain policy and nevertheless not realize what that reason is', 'uses the key term "prohibition" in two different senses', 'infers, merely from the claim that a practice has a certain desirable consequence, that this consequence must provide a motivation for the practice', 'infers, merely from the claim that a certain cultural phenomenon has no economic explanation, that the explanation of this phenomenon must be spiritual or moral']