Rene Descartes and David Lewis have both tried to define a person, and how we can differentiate between those who are and are not a person. I argue that they are both wrong, and that a person is a sentient being, who is self-aware. Apart from those criteria, a person must also live by and follow some sort of moral code or set of rules. Finally, personhood ought to be measured in varying degrees, like a gradient, as opposed to absolutes. Personhood is a very tricky term to define. Descartes and Lewis both try to define it in very abstract ways. Descartes dedicates his sixth meditation to try to answer this question among others. Through his reason he finds that a person is the duality of mind and body, the senses and reason working together to help us shape our realities. Lewis describes personhood in a very similar way, he defines it in terms of mental states and the body’s reactions to those states. Unlike Descartes view, Lewis uses this definition to describe how humans interact with the world, and everything in it. While these views are not incorrect in it of themselves, they are not the whole picture. Following this logic, one could conclude that an animal or an alien are also people, as long as their senses and mind function similarly to how they work in humans. In the essay “Persons and Non-Persons”, Mary Midgley defines “legal person” and “natural person”. Anyone and anything can be classified and seen as a legal person, but natural people are only those that are