Monday, April 3, 2006

Total Recall and the Sixth Day

Another interesting topic from the book Philosopher at the end of the universe. This time it is Arnold Schwarzenegger in the sci-fi movie Total Recall. The scene was on Mars. I love Mars and have watched almost all movie on Mars. There were quite a few in recent years, especially after NASA turned its attention from the Moon to Mars.

Schwarzenegger played Douglas Quaid, a construction worker in the mid-21st century. He was obsessed with dreams about Mars and visited the Rekall company, who implanted false memories of a vacation to Mars in his mind. The procedure went wrong, and Quaid found himself pursued by killers. He was presented with a video message supposedly from his "real" self, Hauser, who had been chief of security on Mars. Quaid had to go to Mars to find the truth.

With the help the mutant rebellion, Quaid discovered the hidden knowledge that he was in his previous life Hauser who was the chief security officer on Mars, and that Quaid was just a bunch of memories implanted on him. The plan of the evil character Cohaagen was to use Quaid to infiltrate the rebellion. The plan succeeded and Cohaagen then wanted to destroy Quaid by implanting back the memories of Hauser. The happy ending was that Quaid escaped his captors and freed Mars. The movie left a question on whether all the events were the Mars vacation memories implanted by ReKall company, or Quaid was a hero who defied changing back to the original Hauser. This is a question of personal identity; what makes you you.

The author started by quoting Heraclitus (赫拉克里特斯 540-480 BC) who said "You cannot step into the same river twice." A river is made up of water; but water is constantly flowing. The river will have changed all its water in a while. Our body is the same. All our cells are constantly being replaced. We do not have the same body as we did a few months ago. Aristotle (亞理斯多德 384-322 BC) had another view. He proposed that things change in two ways: essential changes and accidental changes. Things undergo accidental changes all the time but only essential changes could end the existence of things. Thus personal identity is still intact when accidental changes are going on. However, there is still the problem of defining the essential changes. With significant changes occurring to Quaid and Hauser, are they the same or different person?

In Total Recall, the theme is on the memory theory, that personal identity is made up of the memories of the person. Memories can be implanted into another body, but the person is still the same as he only remembers his own self and acts like he used to be. Or another bunch of memories can be implanted into the same body replacing the old ones, making the body in used by another person having the new memories.

An alternative to the memory theory is the soul theory, that each one of us is essentially a soul embodied in a physical vehicle. This theory stems from dualism that the body and soul are two distinct entities, and it therefore inherits all the problem of dualism. The problem is that the appeal to the soul makes it impossible for one to make any justifiable judgments about a person's identity, even when that person is yourself.

The opposite view to the soul theory is the body theory. According to this view, what you are, essentially, is your body. Here Heraclitus' line about the river implies that the body will not stay the same, although from Aristotle, the body and thus the personal identity, is still safe from accidental changes. However, the advance of science has made the same body hard to define. Body parts transplant is now common. Not only the replacement of limbs by artificial parts, many essential body organs, including the heart, may be replaced. This has shaken the body theory because we still recognize a person's identity even if a majority part of the body has changed.

An extension, or variation, of the body theory is the brain theory. We are just our brains. The body can be changed accidentally but the essential change lies in the brain. Our personal identity exists as long as we have the same brain functioning. An argument against this theory is that the brain, as a physical organ, is also constantly undergoing changes. It can be influenced and changed by drug or disease, but we still consider the person the same.

What we have in our brain are memories, which bring us back to Total Recall and the memory theory. The author admitted that memory theory is not a good term as the brain or the mind has things more than memories. There are various mental states such as beliefs, thoughts, emotions, hopes, fears, etc. A better term should be psychological continuity theory. A person's identity continues to exist and be recognised by others when the same psychological states persist. In this sense, when the memories, or psychological states, of Quaid and Hauser are implanted to the same body, they are different persons and have different personal identities.

The author went on to explore the problem of personal identity through another sci-fi movie by Arnold Schwarzenegger, The Sixth Day. On the Sixth Day, god created man. The movie is about a scientist who developed a method to re-create a person by cultivating a body in the laboratory and implanting the whole memory of that person through cerebral syncording. This fancy copy of a person's mind was recorded by taking a snapshot through the retina. The plot of the movie was that the scientist mistakenly re-created Adam Gibson, a helicopter pilot played by Arnold, thinking he was killed; and then there were two identical Gibsons running around in the movie.

The author called this problem fission of personal identity. If personal identity is based on the psychological continuity theory, what about two distinct bodies having the same psychological states. Are they the same or different persons? In the movie, both Gibsons had the same memories of "their" wife and children, same emotion towards the family, same knowledge and same life experience. However, "their" wife and children could not treat the two Gibsons as the same person if there were two persons in the house. At the end of the movie, one Gibson stayed home and the other went away. We may imagine that there is one person who, at a certain point of his life, go live two different lives. Isn't it mind boggling?

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