thought experiment

ballistic

I just read this at http://www.artsci.wustl.edu/~philos/MindDict/siliconchip.html What do you think? This is one thing I have changed my mind on since being a JW.

silicon chip replacement thought experiment - A thought experiment proposed to support the notion of causal functionalism in Pylyshyn (1980)

To begin the thought experiment, imagine that you are the subject of some mental event--perhaps you are experiencing an intense pain. Now imagine that one of your neurons is replaced by a silicon chip prosthesis that has the exact same input/output profile as the neuron it replaces. At the core of this thought experiment is the presumption that such a replacement would be unnoticeable to you or to anyone observing your behavior. Presumably, you would continue to experience pain even though the physical realization of those mental events includes a silicon chip where an organic neuron used to be. Now imagine that, one by one, the rest of your neurons are swapped for silicon prostheses. Presumably there would be no change in your mental life even though your brain, which was once made of lipid and protein neurons, is now entirely composed of silicon neuronoids. The physical feature of your brain that has remained constant and in virtue of which you instantiate the same mental properties, is not the stuff of which it is made, but instead the causal relations that each part of the brain bears to the other. (The earliest mention of chip replacement thought experiments, as far as I know, is Pylyshyn (1980). For further discussion, see also Chalmers (1996),and Tye (1995).)

Pete Mandik

References

Chalmers, D.J. (1996) The conscious mind: In search of a fundamental theory. Oxford: Oxford University Press. [bookstore]

Pylyshyn, Z.W. (1980). "Computation and cognition: Issues in the foundation of cognitive science." Behavioral and Brain Sciences 3:111-32.

Searle, J. (1992). The rediscovery of the mind. Cambridge, MA, MIT Press. [bookstore]

Tye, M. (1995) Ten Problems of Consciousness: A Representational Theory of the Phenomenal Mind. Cambridge, MA: MIT Press. [bookstore]

Last updated: May 11, 2004

Elsewhere

I thought this was going to be about something like making soap using common household products.

SAHS

The functioning of the human brain?including all the cognitive aspects such as logic, memory, sensation, and emotion?however complex and profound, involves at its most basic level a system of Boolean constructs using binary states, namely ?1? and ?0,? ?on? and ?off.? Such relatively ?simple? binary functioning is the basic neurological ?common denominator? (analogous to the theoretical ?super strings? of the grand unified theory applied as the ultimate ?common denominator? of all matter and energy).

In other words, whether you are experiencing physical pain, an emotional euphoria, or are merely filling out some government form at a vehicle licensing office, or whatever you are doing or experiencing, however complex or abstract, it is really nothing more than the functioning of binary ?1?s and ?0?s. Granted, the algorhythms and processes of the human brain are a wee bit more complex than that which are employed in this Microsoft Word software I am using at this moment, but both are, nonetheless, still manifestation of those binary ?1?s and ?0?s (just much more of them in your noggin). So the very existence of our consciousness is actually the product of an elaborate arrangement of such binary data, which in our brains is in the form of the ?on?/?off? states of our neurons, and in computers exists as . . . well, you get the idea. (Thus lending to the idea that ?the sum is greater than the whole of its parts.?)

The physical feature of your brain that has remained constant and in virtue of which you instantiate the same mental properties, is not the stuff of which it is made, but instead the causal relations that each part of the brain bears to the other.

Actually, the above process is happening to you right now, but instead of your neurons being systematically replaced by some synthetic silicon counterparts, the cells in your entire body are going through a continual process of replacement as needed so that every seven or so years, your physical body has actually been ?replaced? on a molecular-biological level. I?m not sure if this replacement process also applies to the brain neurons, but I would imagine that at least some molecular components in those neurons end up being replaced or rejuvenated in some way, as they are, in fact, cells.

Now, think of this: If I were to burn a copy of this Microsoft Word onto a CD (I?m not sure if Windows would allow such unauthorized copying, but let?s just say for the sake of argument that it can be done), destroy my computer, load it into another computer somewhere else, and run it, then it would, would it not, actually ?be? that program (Microsoft Word) existing somewhere else. Moreover, if I were to (hypothetically!) somehow copy all the ?data? existing in your brain neurons onto some physical intermediary device (a real bitchin? hard drive), kill you, cremate your body, reload that data into another human brain?or even some kind of advanced computer system?then would you ?exist? again somewhere else? Would I have resurrected you? And then, at least relative to your situation, would I then become ?God??

(I apologize if anyone has read this post before having their morning coffee. You need those neurons to be firing efficiently for these thought experiments!)

?SAHS

ballistic

I get your point although I think you will find that adults brain cells do not replace themselves and merely die off.

What I find most interesting about looking at the brain this way, is it breaks down my belief in the brain being "special" in some way... my old belief that a computer cannot be built with conciousness and makes me ponder the meaning of conciousness itself.

sleepy

There is a large assumption there that nerons indeed can be replaced by a silicon chip and that all a neron is, is an input output machine.
The computer analogies never actually explain how we experience things such as sight and sound just how the information can be processed.

ballistic

After reading it I was thinking of a computer system - a large multiprocessor server. It could be given basic needs a bit like our needs for food, sleep and sex. And driving these needs is an underlying imperitive; the need to continue existing. (I'm not a psycologist but I guess we humans must have such an imperitive but what drives it I don't know). The computer would also have inputs, web cams for eyes, microphone etc. It must be able to use these senses to build a picture of it's outside world in order to fill it's needs. I would also say it needs a system of logic so it can formulate ideas on how to fullfill it's needs, and finally a language in order for it express the internal language whether it be to an observer, or just to itself.

Sorry if this sounds crazy - I'm just making it up as I go along!

sleepy

Not sure this would make it conscious, though maybe I am a robot.
exterminate exterminate...

SAHS

?ballistic?:

. . . I think you will find that adults brain cells do not replace themselves and merely die off.

I?m afraid you?re right. I think I remember now from the Creation book?brain cells are the only kind of cells that we retain from birth. Also, I think the brain is pretty much the same size from infancy to adulthood.

?sleepy?:

. . . maybe I am a robot.

Actually, in physical terms, on the most basic level, a person is a robot. If you were the ?First Cause,? and you made such a system as ?ballistic? described?with audio-visual inputs, processing ability, consciousness, and a drive to continue living?using raw materials of carbon, silicon, etc., then that?s exactly what you would end up with?one hum-dinger of a science project!

?SAHS

thought experiment

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