2.5.4: The Ontological Chain of Being

In the western tradition, views on animals can be traced back to the ancient Greeks. Notable ancient Greeks who extended moral consideration to animals include Pythagoras and Plutarch. However, it was Aristotle’s ideas that dominated most of western civilizations views on animals. He argued that humans are most aptly defined by their rational social nature. Humans fulfill their natural and optimal function by reasoning and reflecting with other humans. Non-human animals, in contrast, lack the capacity to reason, and therefore are of lesser moral value. For Aristotle, the fact that animals lacked reason disqualified them as being the type of creatures who could possess moral virtues, and thus not apt to share equal moral considerations. However, being a proto-biologist, Aristotle viewed humans and non-human animals as sharing similar natural interests and dispositions, and thus different in degrees. Nevertheless, the power of reason for Aristotle proved to be a sufficient condition for humans to have dominion over animals, and thus, arguably, opened the door for the exploitation of animals for the next two centuries, especially as he influenced canonical philosophers in their views on animals.

The 18th century Enlightenment philosopher Immanuel Kant developed an ethical system using categorical imperatives, which remains influential in moral philosophy. Succinctly stated, the imperatives hold that humans ought to always be treated as ends in themselves and never as means to ends. Kant argued that only those beings who have the capacity to deliberate on their actions meet the minimum criteria for moral consideration. For Kant, non-human animals lack a good will to deliberate on right (and wrong) actions, and thus humans do not have direct moral duties towards them. However, he also thought that we ought to refrain from animal cruelty because those individuals perpetrating such cruel acts would harm their own moral sensibility. Ethical considerations towards animals are indirect considerations. Thus, Kant is typically interpreted as holding a welfarist position concerning animal ethics.

Aristotle used the “ontological chain of being” arguments to arrive at his position. He situated plants, animals, and humans in a hierarchy where humans sit on top as masters, and animals, plants, and inanimate objects linger on lower levels of being, each descending into lesser forms of being. Kant pushed the power of human reason to the level of a self-governing power, which can be interpreted as drawing a further hierarchical divide between humans and animals. We still live under the veil of the Aristotelian and Kantian view on animals. There are notable deserters of the tradition, however.

British 18th century philosopher Jeremy Bentham found the ontological chain of being argument odious because it presented irrelevant facts regarding the moral consideration and status of animals. He commented that, “... the question is not, Can they reason? nor, Can they talk? but, Can they suffer?” Bentham disavows the idea that an ontological hierarchy of being warrants justification to have absolute and unabashed power over animals. His critique represents an early version of utilitarianism utilized to argue for animal welfare. For Bentham, moral consideration is founded on the basis and capacity to have interests as sentient beings. Thus, Bentham argued that animal capacity to suffer meets the minimum criteria for moral consideration. His work paved the way for animal welfare rights and served as intellectual fodder for future animal rights arguments.