John Locke and René Descartes are two prominent philosophers for each of their philosophical theories. Each brought a new foundation to the subject of philosophy. Their own individual beliefs about personal identity, self, and consciousness have added to the many different perspectives in this field.
The idea of “self” as referred to in the Stanford encyclopedia of philosophy is “some sort of immaterial subject of consciousness” (1). This idea has two different viewpoints which are that our true self is our thoughts and the other view is that it is our feelings. The Stanford encyclopedia of philosophy also states, personal identity “deals with philosophical questions that arise about ourselves by virtue of our being people” (1).
Consciousness is a subject that is still up for debate and many philosophers have different definitions of it. Locke and Descartes have very different perceptions of self, identity, and consciousness. John Locke believed personal identity to be that a person’s memories is what makes them that person. He thought that if someone lost their memories that they were a different person all together.
For example, if a criminal lost his memories then he believed that the criminal should not be punished since they do not remember. Locke perceived that each time a person cannot remember an event that they are no longer the same person as they were. He viewed “self” to be a person’s consciousness or their mind. He believed that the mind is the true essence of a person. Locke said in his book, “We have the ideas but of three sorts of substances: 1. God. 2. Finite intelligences. 3. Bodies,” which means these are the three definite things that exist in life according to him (2).
He goes on to discuss that bodies exist but only that one of them can exist at a time. If there were to be a copy of a body which makes two bodies the exact same, that cannot be true since there can only be one according to Locke. He wrote, “… two things of the same kind should exist in the same place at the same time, we rightly conclude, that, whatever exists anywhere at any time, excludes all of the same kind, and is there itself alone” which explains that he believes that two things cannot exist at the same place and time (2).
If there were a way to copy and transplant memories of a person into other people then there would be multiples of the same person. This cannot happen since no two alike things can exist at the same time but if there are more than one person with the same memories then that makes this theory impossible. René Descartes believed personal identity to be that people only exist so long as they are thinking. He believed that “I think therefore I am” which is the foundation of his philosophical theory.
Descartes theorized that reality could be a dream and questioned if memories are real. Descartes wrote in his book, “… for whether I am awake or dreaming, it remains true that two and three make five, and that a square has but four sides; nor does it seem possible that truths so apparent can ever fall under a suspicion of falsity [or incertitude]” this is explaining that he questions the supposed facts of consciousness and mathematics (3). He questioned everything from religion to mathematics to the world itself.
Believing God may be making his mind believe he is on what he believes is Earth but it is really another planet. His thought process is that if God can make an entire world and everything on it that he could also make them believe whatever he wanted them to. Descartes believes God is real but also believes that God could be making everyone think they live in one reality when it is really another all together.
His main argument is that this is all a dream and no one can know for sure if it is or is not but that as long as people are thinking then they can know they exist. Descartes viewed the self as the mind in that without the mind there would be no dreams or thoughts which is all that the self is made of. He viewed that the mind is entirely different from the body in a theory he called dualism. He believed that the mind controlled the brain and the body was separate all together.
This means that the mind and brain occupied the same space but the mind was in charge of the whole operation. The body, according to Descartes, is just a functional way of getting the mind around and protecting it from the world. This theory has fascinated people for generations that the mind, brain, and body are separate. The difference between Locke’s view and Descartes’ view is Locke believed that memory was the core of personal identity while Descartes believed that the mind was the core of personal identity.
Both philosophers believe that the mind is the essence of what makes a person but Locke is more focused on memory while Descartes is focused on thoughts. John Locke thought that a person is what they remember so if they forget something then they are no longer that person. If someone could not remember when they took the trash out then they are a different person than the one who took the trash out. Descartes on the other hand, thought that as long as someone is thinking that they exist.
The moment someone stops thinking is when they stop existing. Descartes’ view is the much more logical perspective because his theory is that no one can prove if reality is a dream or not. No one can demonstrate that the lives we live are meaningful or that anything one person sees is the same as what other people see. His focus is on the mind and its thoughts rather than the body or memory.
Locke focuses more on memory which is a weak way to base life of off. Every person has thoughts and that is what makes them different from the rest of humanity. Thoughts let people know that they exist and there is a purpose to their lives. This world may be a dream or artificial but at least people know that they exist because they are constantly thinking about what to do next.
Descartes has a stronger foundation that he acknowledges that no one can prove any of this world or anyone’s lives exist. His basis is that thinking is the only part of life that truly matters. It is a sound argument to recognize that anything and everything could be fake and no one could ever know.
Producing thoughts constantly is the only existent factor in reality that we know is real. Locke’s view has flaws and holes in his theory because memory is not always reliable. No one can remember what they did at any certain time three weeks ago unless it was a monumental moment. According to Locke’s theory this means that a person changes every time they forget what they had for breakfast. People do change but they do not change that often. Memory is not reliable enough to base an entire reality of off. Eyewitness cases are almost entirely wrong because no one’s memory even when in a heightened state of emotion can remember every detail of a scene.
Locke also believes that a body can only be in one place and only one matter can exist. If there were a carbon copying machine that could copy a person’s body then that makes that person in the same place but two different bodies. This makes no sense because if someone were able to take out a person’s memories and display them then everyone would have those memories thus making everyone one person.
All of humanity cannot be one person but if everyone had the same memories then Locke says we are that person. His theories are too contradicting to base a foundation off of. These two influential philosophers paved the way for different ideologies for centuries to come. Both offered two unique perspectives on ways to view the world we live in. Descartes and Locke both valued the mind over the body as the crux of existence. Each of these great minds provided new ways to look at reality.
- Olson, Eric T. “Personal Identity.” Stanford Encyclopedia of Philosophy, Stanford University, 9 July 2015, plato.stanford.edu/entries/identity-personal/.
- Locke, John. An Essay Concerning Human Understanding. W. Tegg, 1690.
- Descartes, René. Descartes’ Meditations on First Philosophy. 1901.