The Nature of Consciousness

Piero Scaruffi

(Copyright © 2013 Piero Scaruffi | Legal restrictions )
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These are excerpts and elaborations from my book "The Nature of Consciousness"


The Machinery of the Mind

If i replace every neuron in your brain with an artificial neuron made of silicon that carries out the exact same function, are you still you? If you answer "yes", you just answered "yes" to the question whether machines can be as conscious as humans. This thought experiment is more than just a neuroscience variant on  Theseus's paradox that asked whether a ship rebuilt exactly the same with different parts is still the same ship.  When it comes to the brain, we're not only asking whether it's still the same brain, but also whether it's still an "i" (a mind, a conscious being) and, more importantly, whether it's still the same person. As chip implants will become common to replace parts of the brain that have been damaged, this will no longer be an academic question: you may have to decide whether to replace a piece of your brain with a piece of silicon that makes your brain work “perfectly well”, but is that thing that is “working perfectly well” you? Prosthetic limbs replace limbs that are not responsible for our conscious life. The brain, as far as we know, is. Replacing a piece of the brain with “prosthetic brain regions” implies a belief that our conscious life does not depend on the “stuff” the brain is made of, only on the processes that are going on, in which case one could build an entirely artificial brain that is a conscious being.

The fascination with the idea of building an artificial mind dates from centuries ago. Naturally, before building an artificial mind one should first figure out what kind of machine the human mind is like. The limit to this endeavor seems to be the complexity of the machines we are capable of building. Descartes compared the mind to water fountains, the Austrian psychologist Sigmund Freud to a hydraulic system, the Russian physiologist Ivan Pavlov to the telephone switchboard and the US mathematician Norbert Wiener to the steam engine. Today our favorite model is the electronic computer. Each of these represented the most advanced technology of the time. The computer does represent a quantum leap forward, because it is the first machine that can be programmed to perform different tasks (unlike, say, dishwashers or refrigerators,  which can only perform one task).

There is very little similarity between an electronic computer and a brain. They are structurally very different. The network of air conditioning conducts in a high-rise building is far more similar to a brain than the motherboard of a computer. The main reason to consider the electronic computer a better approximation of the brain is functional, not structural: the computer is a machine that can achieve a lot of what a brain can achieve. But that alone cannot be the only reason, as machines capable of representing data and computing data could be built out of  biological matter or even crystals. The real reason is still that the computer is the most complex machine we ever built. We implicitly assume that the brain is the most complex thing in the world and that complexity is what defines its uniqueness. Not knowing how it works, we simply look for very complex apparati. Our approach has not changed much since Descartes. We just have a more complex machine to play with.

It is likely that some day a more complex machine will come by, probably built of something else, and our posterity will look at the computer the same incredulous way that today we look at Descartes’ water fountains.


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