In spite of the considerable literature nowadays existing on the issue of the moral exclusion of nonhuman animals, there is still work to be done concerning the characterization of the conceptual framework with which this question can be appraised. This paper intends to tackle this task. It starts by defining speciesism as the unjustified disadvantageous consideration or treatment of those who are not classified as belonging to a certain species. It then clarifies some common misunderstandings concerning what this means. Next, (...) it rejects the idea that there are different kinds of speciesism. Such an idea may result from confusion because there are (1) different ways in which speciesism can be defended; and (2) different speciesist positions, that is, different positions that assume speciesism among their premises. Depending on whether or not these views assume other criteria for moral consideration apart from speciesism, they can be combined or simple speciesist positions. But speciesism remains in all cases the same idea. Finally, the paper examines the concept of anthropocentrism, the disadvantageous treatment or consideration of those who are not members of the human species. This notion must be conceptually distinguished from speciesism and from misothery (aversion to nonhuman animals). Anthropocentrism is shown to be refuted because it either commits a petitio principia fallacy or it falls prey to two arguments: the argument from species overlap (widely but misleadingly known as “argument from marginal cases”) and the argument from relevance. This rebuttal identifies anthropocentrism as a speciesist view. (shrink)