Why Rationality does not Matter in a Cross Species Comparison

Too often are nonhuman animals discounted in moral deliberations simply due to the fact that they are not “fully rational.” The capacity forrational human rational thought, then, is what is often said to entitle a being to serious moral consideration. The belief that animals have an inferior status to humans , or perhaps no moral status at all, often stems from Kant who wrote that nonhuman animals “are not self-conscious and are there merely as a means to an end. That end is man… Our duties towards animals are merely indirect duties toward humanity.”

While we might grant that rationality is a distinguishing feature of human life, we might pause to question whether this feature entails the moral superiority of humans over animals. We might ask why it just so happens that the distinguishing mark of human life is necessarily the most “superior feature”? There are also distinguishing features of animal life that are rarely considered- for example, bears are said to have an incredible sense of smell (the best sense of smell of all animals) and a cheetah is the fastest land animal (they can run approximately 3X faster than the best human runner-113km/h).

bear incredible sense of smellSo rationality is the distinguishing feature of human life, smelling is the distinguishing feature of bear life, and speediness is the distinguishing feature of cheetah life: how then, are we entitled to conclude that rationality is the best feature of the three: the feature that makes human beings more valuable than animals?

We might first ask who exactly is this feature (rationality) “good for”? While we can admit that rationality is a good characteristic for humans to possess, we might stop to consider whether it is a good thing for a bear or a cheetah to possess and if it makes sense to claim that if a bear or cheetah does not have it, they are somehow morally inferior to beings who are rational.

When we claim that humans are superior to animals because animals “lack rationality,” we make, according to Rush Rhees, a category mistake. Rationality contributes to value in human life, but it is not necessarily valuable in bear life; thus to say that a bear “lacks rationality” (and is thus inferior to the human is a category mistake)—there is nothing a bear qua bear is missing.

Rhees goes on to point out that there are cases where certain humans, i.e. marginal human beings such as infants, the senile, severely cognitively disabled, are without rationality; in such cases it makes sense to say that a marginal human lacks rationality because there is something a marginal human being qua human is missing. While a marginal human being might be said to be defective for lacking rationality, we cannot say that a nonhuman animal is defective for lacking something that is only part of the fabric of human life- not bear life.

So while we might accept that the fabric of human life is different from the fabric of nonhuman animal life, we can’t then jump to the conclusion that human life is “more superior.” The fact that humans are “different” than animals in regard to their capacity for rationality does not entail that humans are superior to animals any more than the fact that bears are “different” from humans in regard to their capacity to smell does not entail that bears are superior to humans. It just does not follow that lacking a feature, like rationality, which is valuable within human life, then makes animal life less significant.

Difference, then, does not equal superiority.

In conclusion, we should stop making cross species value comparisons between animals and humans by evaluating both humans and animals according to a characteristic that is a valuable feature of only human life. The fact that an animal does not possess rationality does not entail that it is morally inferior- it just entails that there is a difference in the shape of human and animal lives.


**This post was motivated by (and can be viewed as a blending of) the ideas in the documentary The Superior Human and the writings of Rush Rhees.