Jan,
Good post and some good questions.
If that is the case, then surely a recently deceased, and in tact body could be brought back to life, either by repair or new parts, in the same way one could repair a (dead) computer.
Yes that is true and we are seeing that happen far more frequently in recent times. Usually heart failure meant permanent death but modern resuscitation techniques are able to restart hearts under such conditions. Repairs can then take the form of heart bypass surgery and similar techniques. We also have seen heart transplants and more recently complete artificial hearts.
Kidney failure is another area where death would result but kidney dialysis can solve that problem. Cancer used to be a sure killer but surgery and chemotherapy can often solve some of those problems.
But meaningful resuscitation does depend on accessing the patient very quickly before the brain patterns undergo irretrievable decay. There are cases where the body can be kept alive by machines but the brain patterns had decayed meaning there is no control function left. When the support machines are turned off the patient’s shell then simply dies.
then a computer, such as the type you mentioned, which is just around the corner, will have consciousness. This is where I have my doubts.
Ok and that I think is a fair comment.
If a computer is executing a highly complex program, where would the computers consciousness reside?
And here I think will be the crux of our discussion. We need to agree on what is meant by consciousness, and it doesn’t seem to as intuitive as many believe. I’ll come back to this.
But first I’d like to finish the comparison between computers and the brain, as this will lead directly into how consciousness can be achieved on a computer.
From what is understood about digital computers, the CPU will be carrying out only one instruction at any given time, and the millions of instructions comprising the rest of the program will exist only as an inactive record in the computer’s memory. So it can’t suddenly have a brainwave, a change of plan, like us. In what way can we correlate this systematic activity with the conscious perception of thoughts and feelings?
You are both right and wrong. Yes a given CPU only executes one instruction at a time. Well almost. Most modern CPUs pipeline many instructions in parallel, but yes ultimately the one at the end of the pipe is executed before the others.
Parallel Processing Systems.
But most business computers have multiple CPUs. These are configured as SMPs (Symmetric Multi Processors), or MPP (Massively Parallel Processors). In an SMP multiple CPUs operate independently and access a common memory. The programs that run on such systems are designed so that they can fork multiple tasks that can execute in parallel. An MPP consists of a cluster of single CPUs each with its own dedicated memory but a very high bandwidth communication bus links the CPUs. In such systems programs also run in parallel and can independently process their own data that is often merged together as an end result.
You should think of each neuron in the human brain as being a small CPU, capable of functioning independently. And memory in the human brain is not held in one place but seems to be dispersed. The computer equivalent to the human brain will be the Massively Parallel Processor (MPP) architecture.
The Complexity of the Human Brain.
The human brain contains somewhere around 100 billion neurons and 100 trillion synapses. That's the hardware. The software of the human brain is the result of millions of years of evolution and contains perhaps tens of thousands of complex functional adaptations. The brain itself is not a uniform lump but a highly modular supersystem; each of the two hemispheres of the cerebral cortex is divided into 52 areas, most of which can be further subdivided into five or six maps. The evolutionarily ancient subcortical structures are more modular still.
Human neurons fire approximately 200 times per second, using signals that travel at a maximum of 100 meters per second. By comparison, my computer's CPU operates at 850 million clock cycles per second, and the speed of light is 300 million meters per second; the reason a human brain has around a hundred million times as much raw computing power as my computer is that a human brain has 100 billion neurons and 100 trillion synapses operating in parallel.
But when we build a computer to the same power of the human brain we would not need to have 100 billion CPUs. A neuron is really very slow compared to existing CPU power, and especially compared to the CPU power that is expected in a few years. This means that with just simple time-sharing techniques a single high power CPU will be able to easily perform the same tasks as thousands of neurons in the same time frame.
Building the machine to duplicate brainpower is not going to be the problem, and notice that it will not be difficult to exceed human brainpower very quickly; a millionfold is well within projected technical limits.
Massive Parallelism and Consciousness.
And if the human being is nothing more than a machine, then how comes we are conscious and are able to?
How come we are capable of abstract and subjective thought, which has clearly been demonstrated time and again, to be sudden and unplanned?
And here we return to the real issue.
I hope I have shown you that we can build the hardware to do the same as the brain, but what really matters is the software. And this is where it is very important for to forget the current relatively primitive power of modern computers, they are some 100 million times slower than your brain.
A few years ago IBM’s Deep Blue beat Kasparov at chess. When beaten, Kasparov stormed out because he detected Deep Blue using subtle strategies and subjective techniques that he had never seen in a machine before, he was convinced there were humans really making the moves.
Deep Blue did make the moves but it had not been programmed with any AI techniques, it simply used raw power to consider many more combinations of moves than the human brain was capable. In short Deep Blue was capable of apparent subjective thought.
Now consider these steps.
1. Deep Blue with 100 million times the power built as an MPP system.
2. Software written that specifically exploits AI techniques based on human brain neural networks.
While I can’t prove that the result will be the equivalent to what we call human consciousness but I think there is a good chance that it will.
I am not challenging you, I would like to get to the bottom of whether or not we are primarily an entity, outside of this manifestaition, which links itself with matter which then becomes animated. The missing link, if you like.
So what I am suggesting is that Massive Parallelism that we see in the brain can be accurately replicated in computer hardware, and that properly designed and written AI software will achieve the equivalent of human consciousness.
Here is a link to an AI project dedicated to the creation of friendly AI.
http://www.singinst.org/CFAI/index.html
Will we be able to create the equivalence of human consciousness (whatever that means) on a computer? I don’t really know, but I hope so since I believe my long-term future depends on this.
Is there a supernatural soul that provides human consciousness? I don’t know that either, but based on my studies I don’t think so.
I hope you are still with me at this point and I haven’t bored you too much with my computing lecture. You might like to know that I manage a research and design department for a major computer manufacturer here in Silicon Valley, specifically in the area of MPP systems.
Cris
But sure, having eternal life could be wonderful.