Human interactions with nonhuman animals should be guided solely by the impact of these interactions with other human beings, and not upon any perceived impact upon nonhuman animals themselves. This argument is based largely upon Descartes' understanding of the essential difference between humans and nonhuman animals. Descartes' argues that the body is external to the mind, and that non-human animals do not possess the pure, thinking mind of humans. Thus, Descartes argues that nonhuman animals are simply machines, and that human treatment of animals should only be guided by the impact of such interaction upon other humans. In contrast, thinkers like Anthony Weston have argued that similarity of human and animal perception and experience means that human should treat animals as feeling beings. Similarly, Abram argues that the human connection with the natural world should govern our interaction with animals. Descartes' arguments for the uniqueness of human thought essentially counter both of these arguments. The Arguments of Descartes and Abram

Descartes' arguments about the nature of the world and nonhuman animals rest strongly on his underlying philosophy that the body is external to the mind. Through this argument, he notes that all that we can ever truly know about the world comes from our own thoughts. As such, humans learn about the external universe through a priori knowledge within our mind (Palmer).

To Descartes, the world was divided into the pure, thinking mind that was possessed solely by humans and unthinking, mechanical matter that was possessed by animals, plants, minerals, and the human body. In Animals are Machines, Descartes notes, "there are (no humans) so depraved and stupid, without even excepting idiots, that they cannot arrange different words together, forming of them a statement by which they make known their thoughts, while, on the other hand, there is no other animal, however perfect...

In Animals are Machines, Descartes argues that the behaviors observed in animals can be easily explained to be automatic and mechanical in nature. Thus, animal behavior can be explained without ascribing thought and consciousness to animals. Given that the principle of parsimony dictates that the best answer is the simplest answer, Descartes asserts that nonhuman animals are simply machines made up an intricate assembly of individual parts.
In The Spell of the Sensuous: Perception and Language in a More-Than-Human World, David Abram draws a fundamentally different picture of the human relationship to nonhuman animals, plants, and natural objects such as rivers and mountains. Abram argues that the development of human language created an abstract world that falsely caused a disconnection between humans and the natural world. Thus, Abram essentially argues that Descartes' dichotomy of mind and body (which are at the root of his belief that animals are purely mechanistic in nature) resulted from a great, and false, disconnect between humanity and the rest of nature. In contrast, Abram argues that the human mind and body stem from a larger connection with the natural world, and continue to depend on the reciprocal interaction with the larger natural world.

Treatment Nonhuman Animals

Descartes argument that animals are little more than intricate machines logically led to his conclusion that humans have little responsibility to nonhuman animals. To Descartes, humans would have no more responsibility to a cat or dog than they would have to a piece of machinery such as a dishwasher or car. Any responsibility that humans would have to animals or the natural world would rest only on how the treatment of animals or the natural world would impact…