of speciesism (which he termed 'humanism'), arguing that "Why are fancy properties which are grouped under the label of personhood "morally relevant" to issues of destroying a certain kind of animal, while the property of being a human being is not?" Williams states that to respond by arguing that it is because these are properties considered valuable by human beings does not undermine speciesism as humans also consider human beings to be valuable, thus justifying speciesism. Williams then states that the only way to resolve this would be by arguing that these properties are "simply better" but in that case, one would need to justify why these properties are better if not because of human attachment to them. Christopher Grau supported Williams, arguing that if one used properties like rationality, sentience and moral agency as criteria for moral status as an alternative to species-based moral status, then it would need to be shown why these particular properties are to be used instead of others; there must be something that gives them special status. Grau states that to claim these are simply better properties would require the existence of an impartial observer, an "enchanted picture of the universe", to state them to be so. Thus Grau states that such properties have no greater justification as criteria for moral status than being a member of a species does. Grau also states that even if such an impartial perspective existed, it still would not necessarily be against speciesism, since it is entirely possible that there could be reasons given by an impartial observer for humans to care about humanity. Grau then further observes that if an impartial observer existed and valued only minimalizing suffering, it would likely be overcome with horror at the suffering of all individuals and would rather have humanity annihilate the planet than allow it to continue. Grau thus concludes that those endorsing the idea of deriving values from an impartial observer do not seem to have seriously considered the conclusions of such an idea. Objectivist philosopher Leonard Peikoff stated: "By its nature and throughout the animal kingdom, life survives by feeding on life. To demand that man defer to the 'rights' of other species is to deprive man himself of the right to life. This is 'other-ism,' i.e. altruism, gone mad." Douglas Maclean agreed that Singer raised important questions and challenges, particularly with his argument from marginal cases. However,