It was Rene Descartes who coined “Cognito ergo sum” -”I am thinking therefore I exist” or more popularly “I think therefore I am”.
What Descartes is trying to prove is that there is a Élan Vital, A soul, a metaphysical essence that exists as a separate entity from the body. This is known commonly as Dualism. Descartes’ reason for this was to establish firm knowledge. Without going into too much detail, he needed to prove God existed, as a guarantor of firm knowledge. So, his taking up of Dualism was part of a long argument to establish that we can have firm knowledge.
I will first discuss some context before considering whether or not this idea has been proved. The origins of the doctrine of Dualism, generally, traces back to ancient Greece. More specifically to the religion of Orphism. Orphism held that humans have souls, that Transmigrated after death, presumably into other human beings. Pythagoras, I believe, was a member or at least followed this religion. He further elaborated on the idea of a soul, as timeless, eternal and otherworldly. Plato was greatly influenced by Pythagoras , and in turn greatly influenced Christianity and the early church thinkers.
It would seem that most cultures have this idea of a soul, however, (ie there is a “real me” behind my eyes ). The other day I read an anecdote concerning an African tribal custom. When two tribes were in dialogue with one another, they would send a emissary to walk from village to village, when the emissary arrived he would take the rest of the day to rest, (he had, perhaps, only walked a few miles) the reason was to let his soul catch up (imagine what our lives would be like if we believed this!)
There is one major world religion or philosophical tradition that differs on this issue, and that is Buddhism. There is, however, a contradiction lurking within Buddhist thought. Buddhism posits no soul, or Atman. There is no thinker behind the thoughts, no seer who sees. Thoughts are impermanent and insubstantial. At first look this would mightily disagree with Descartes, Christianity and our common sense, indeed it does. However, there is a problem. If there is no soul, no distinct self, then what about Nirvana? (The idea of souls or essences transmigrating) It would appear that Buddhism has contradicted itself before it’s even tied its shoes. This does seem to be the case, but, Buddhism was influenced by Brahmanism (which believe in a soul) and, probably, picked up the Nirvana idea from them. It would seem that the Nirvana idea was grafted onto Buddha’s thought and hence Buddhist theology. As Laplace would say “it works fine without that assumption”.
Buddhism, however, is unique, fantastically so, in recognising that there is no “Ghost in the Machine”. I might be begging the argument here, but the vast majority of philosophers and scientists especially scientists working on the brain reject Dualism. Why? Well for Buddhists they argue that thoughts and feelings are generated by a process of cause and effect. The way our language, cognitive perception and emotions operate-- producing a by-product- an impression of a self. This self or ego is really a response to fear, hatred and desire. Thoughts come up and we latch onto them believing thoughts or impressions as expressing our true selves (little homunculi in the brain or the soul.). Buddhism, however, sees these thoughts as empty, they appear and then dissipate. Buddhists see this process in meditation and claim to be able to be free from the prison of thought by attaining enlightenment. So, rather than saying “I am angry, and I am angry at him” they frame it “this body is experiencing anger, and it is experiencing anger by my expectations of how this person should behave.” In short, a famous saying in Zen is “don’t believe your thoughts they are not real”.
There are a few notable exceptions. The Stoics had a similar belief to the Buddhists. David Hume, a Scottish philosopher, seemed to have transcended dualism, Hume’s “bundle theory”. I believe in short, that Hume believed that we notice impressions, “thoughts, feelings, sensations” but it is superfluous to put forward that there is someone who is experiencing the sensation. Ie there is simply the impression without the added thought that it is happening to someone.
The problems with the theory of Cartesian Dualism.
The problems with the Cartesian theory are. 1. It is circler. If there is someone or something who resides in the brain that is watching, who watches it? 2. Casper the friendly ghost paradox. Ever wonder how Casper is able to both fly through walls and hold sticks of wood in his hand? Neither do I. Descartes holds that the soul is immaterial, but how does immaterial interact with the material while staying immaterial? This paradox leads me to. 3. Where is the captain of our ship? Where is the soul? Where is the part of the brain that houses the place where I think? Where does the élan vital reside? I am reminded of the joke Douglas Adams made. A modern day scientist explains to someone from the past how a TV works. He opens it, showing that there is no “little men” inside. He explains how the TV works, but in the end the man says “there is probably still a few little men in there”. This leads me to- 4. Redundancy. Most, if not all, brain scientists explain the workings of the brain, and hence our sense of selves in purely material and naturalistic terms. Bringing up Laplace, again,--we don’t need that hypothesis. Leibniz in response to Descartes, conceived of the brain like a barn with lots of different machinery and processes, taken together they produced an effect--the impression of a self. Nowhere though, could any person point and say “there is where I reside, this is the part of the brain which makes me a person”.
Most people, reading this, will probably conclude that this is a lot of sceptical nonsense. And in one way they are right. This calls for a good error theory. Ludwig Wittgenstein was asked how could so many people be wrong about the earth rotating the sun. His famous reply was well how would it look if the earth was rotating the sun?
In terms of our everyday interaction with people, we perceive people (and animals) as agents. Agents that want something, that have goals, aspirations and beliefs. They are agents with intention, they also show regular features. Ie personality “I don’t like coffee, and tennis is my favourite sport I play it every Saturday” and memory “I remember when we were all at school, I was a quiet lad and did not get into trouble.” Rocks don’t have intentions nor do they have memories, hence we don’t think they have selves and hence we can throw them about with abandon (hopefully not near windows alas).
I am a self. To clarify this, I mean I am a person who has unique personality and memories different from other people. This is a perfectly fine definition. The problem is when we start to go in search on where this SELF IS. We will not find it, its not there. So its not I think therefore I exists, its rather I exist therefore I think.
If we define personhood in terms of unique personal experience and memories. Then it follows that, if we alter and remove those features that make a person a person or a human body a unique individual then that person is no longer the same person.
Lets say we have X, and A and B constitute X necessarily and sufficiently. If we remove A and B then X is no longer X. lets say we want X to be Z, and factors D and E make up Z. So if we implant D and E into the entity that was X then it becomes Z.
Who cares? Well this is a potential problem. Lets call it the Clockwork Orange Paradox.
Imagine that Science can do this. Science can alter memories and personality. Imagine then, that child rapists and murders can be changed in this way. Their memories of the crime, and the personalities and life experiences that led them to commit the crimes have been altered. So, the person is no longer guilty of the crime and is free to carry on a new life.
I am sure you feel uneasy at this possibility (such possibilities are not that fanciful). And there is good reasons to oppose such an idea. However, logically and empirically it would be true that the person (the child killer) no longer exists, but this is counterintuitive to the very innate ideas we have of personhood (souls and invisible essences and so on.) So to clarify, we have reached a “repugnant conclusion”. A conclusion that, although justified rationally, is still offensive, disgusting, or “repugnant” to our emotions or perceptions.