I'm no expert in this area so I welcome corrections to my rough numbers below. Approximate number of human neurons: 1.0e11
Approximate number synapses in a human: 1.0e14
These are big numbers, but not impossibly big numbers. There are different kinds of
neurons, and signals on synapses are not simply binary. However, even with these
complications, the hardware needed to reach these scales isn't hard to imagine. Transistors in XBox One: 1.0e09
Brains are biological computers so they suffer from very slow switching speeds at the neural
level. Neurons run in parallel, but they are not fast: Approximate neural switching speed: 1.0e03/sec
Even if all of the synapeses could sustain this rate in parallel (they can't) and even if all of the brain was 100% occupied with solving a single task (it isn't) this would mean that we absolutely can't compute faster than: Speed * synapses (brain ops per second): 1.0e17/sec
For comparison, the fastest bitcoin hardware I see is advertised to operate at the
following speed: Minerscube 15 (hashes per second): 1.5e12/sec
And a regular GPU is capable of simple instructions that run at the following speed: AMD Radeon HD 6990 32-bit instructions: 2.6e12/sec
From this we can see that hardware is catching up with the raw computing ability of
the human brain. Now consider the problem of programming a brain. It isn't necessary to
program every synapse. The brain learns, and essentially programs itself. To see
why this is true consider the programming that we are born with: Bits of information in human genome: 1.0e10
This is far less than the number of synapses that we have. Therefore, the brain must
program itself, somehow.Now, to address the argument about evolution taking millions of years. First, we can
evolve programs much faster than nature can evolve humans. There have been, perhaps,
100 million generations of humans. Even if it takes six seconds of computing time to
run an evolutionary computation for a single generation it will take no more than
20 years to run over 100 million generations. Brute force evolution isn't the only way to build strong AI. A program can exhibit
behavior that we don't anticipate. I've written simple programs that beat me easily
at games such as Othello or Freecell. Finally, once machines get smart enough to design other machines there may be a
rapid acceleration of progress in this area as we employ them in designing subsequent generations. I feel that strong AI may pose a significant risk to humans; consequently, we should
proceed with caution. Here is a thought experiment. If a chimpanzee could be taught to drive, would you trust it to pick your kids up from school? What sort of value judgements would it make in the case of an impending emergency? Would you let an elephant baby sit for you? Even if was much "smarter" than a normal elephant? Strong AI will not be like us. It will learn and develop without a human body, and it will not interact with the world and society as we do and may end up being very foreign to us. Will it be sociopathic? Or will it be like whales, intelligent, but mysterious, perhaps spending all its time singing AI songs to other AIs. |