In the comment thread to my last post there was a lot of discussion about computers and their relation to intelligence. This is my understanding about computers. They are just very powerful calculators, but they do not “think” in any meaningful sense. By this I mean that computer hardware is nothing but an electro-mechanical device for operating computer software. Computer software in turn is nothing but a series of “if then” propositions. These “if then” propositions may be massively complex, but software never rises above an utterly determined “if then” level. This is a basic Turing Machine analysis.
This does not necessarily mean that the output of computer software is predictable. For example, the “then” in response to a particular”if” might be “access a random number generator and insert the number obtained in place of the variable in formula Y.” “Unpredictable” is not a synonym for “contingent.” Even if an element of randomness is introduced into the system, however, the way in which the computer will employ that random element is determined.
Now the $64,000 question is this: Is the human brain merely an organic computer that in principle operates the same way as my PC?” In other words, does the Turing Machine also describe the human brain ? If the brain is just an organic computer, even though human behavior may at some level be unpredictable, it is nevertheless determined, and free will does not exist. If, on the other hand, it is not, if there is a “mind” that is separate from though connected to, the brain, then free will does exist.
This issue has been debated endlessly, and I refer everyone to The Spiritual Brain for a much more in depth analysis of this subject. For my purposes today, I propose to approach the subject via a very simple thought experiment.
First a definition. “Qualia” are the subjective responses a person has to objective experience. Qualia are not the experiences themselves but the way we respond to the experiences. The color “red” is the classical example. When light of wavelength X comes into my eye, my brain tells me I am seeing the color red. The quale (singular of “qualia”) is my subjective experience of the “redness” of red. Maybe the “redness” of red for me is a kind of warmth. Other qualia might be the tanginess of a sour taste, the sadness of depression, etc.
Now the experiment: Consider a computer equiped with a light gathering device and a spectrograph. When light of wavelength X enters the light gathering device, the spectrograph gives a reading that the light is red. When this happens the computer is programmed to activate a printer that prints a piece of paper with the following statement on it “I am seeing red.”
I place the computer on my back porch just before sunset, and in a little while the printer is activated and prints a piece of paper that says “I am seeing red.”
Now I go outside and watch the same sunset. The reds in the sunset I associate with warmth, by which I mean my subjective reaction to the redness of the reds in the sunset is “warmth.”
1. Did the computer “see” red? Obviously yes.
2. Did I “see” red. Obviously yes.
3. Did I have a subjective experiences of the redness of red, i.e., did I experience a qualia? Obviously yes.
4. Did the computer have a subjective experience of the redness of red, i.e., did it experience a qualia? Obviously no.
Conclusion: The computer registered “red” when red light was present. My brain registered “red” when red light was present. Therefore, the computer and my brain are alike in this respect. However, and here’s the important thing, the computer’s experience of the sunset can be reduced to the functions of its light gathering device and hardware/software. But my experience of the sunset cannot be reduced to the functions of my eye and brain. Therefore, I conclude I have a mind which cannot be reduced to the electro-chemical reactions that occur in my brain.