The predation problem or predation argument refers to the consideration of the harms experienced by animals due to predation as a moral problem, that humans may or may not have an obligation to work towards preventing. Discourse on this topic has, by and large, been held within the disciplines of animal and environmental ethics. The issue has particularly been discussed in relation to animal rights and wild animal suffering. Some critics have considered an obligation to prevent predation as untenable or absurd and have used the position as a reductio ad absurdum to reject the concept of animal rights altogether. Others have criticized any obligation implied by the animal rights position as environmentally harmful. Responses from animal ethicists and rights advocates have been varied. Some have rejected the claim that animal rights as a position implies that we are obligated to prevent predation, while others have argued that the animal rights position does imply that predation is something that we should try to avert. Others have asserted that it is not something that we should do anything about now due to the risk that we could inadvertently cause significant harm, but that it is something that we may be able to effectively take action on in the future with improved knowledge and technologies. Historical views Problem of evil Predation has historically been viewed as a natural evil within the context of the problem of evil and has been considered a moral concern for Christians who have engaged with theodicy. Natural evils have been sometimes thought of as something that humans should work towards alleviating, or as part of a greater good which justifies the existence of this type of evil. Thomas Aquinas advocated the latter view, arguing that "defects" in nature such as predation led to the "good of another, or even to the universal good" and that if "all evil were prevented, much good would be absent from the universe". Within Christian and Hebrew Scripture, there are several prophecies which describe a future Heaven or Earth where predation is no longer a feature of nature, including Isaiah's prophecy that "[t]he wolf shall live with the lamb, the leopard shall lie down with the kid, the calf and the lion and the fatling together, and a little child shall lead them." In his notebooks (written between 1487 and 1505), Leonardo da Vinci questioned why nature was not structured in a