AI Brains Will be Analog Computers, Of Course

December 4, 2014

That same interview with Jaron Lanier had a whole bunch of insightful comments by famous futurology-type people, and I thought one in particular was excellent. George Dyson pointed out something that should be totally obvious if people would only think about it – that a true AI machine that really thinks for itself can’t be a digital computer, but it must be an analog computer.

Autumn leaves in Kinuta Park - Nov. 23, 2013

Autumn leaves in Kinuta Park – Nov. 23, 2013. This year’s were different and not quite as good. (Enlarge) By the way, here are some fake autumn leaves outside a shop.

Here’s a quote from the actual comment that Dyson posted:

The brain (of a human or of a fruit fly) is not a digital computer, and intelligence is not an algorithm. … The brain is an analog computer, and if we are going to worry about artificial intelligence, it is analog computers, not digital computers, that we should be worried about.

Isn’t that obvious? Our brains are not digital, so why would we expect true AI machine brains to be digital?

Dyson also points out something less obvious – that intelligence is not an algorithm. He’s right on this point too because intelligence means the running of an algorithm in pursuit of a goal. There’s a big difference between an algorithm written down somewhere (sitting inert) and an algorithm in action, with the juices flowing through it.

It’s the same difference between a picture of a bird flying and an actual bird in flight. Or between a traffic light turning green and the traffic actually going. Vroom-vroom! It’s the difference between a symbol and the thing symbolized. Or as John Searle would say, it’s the difference between syntax and semantics.

The point is that we’re never going to build true AI by writing down instructions for AI behavior. The only way to succeed is by building an AI machine that will really behave, in the real world. Not instructions, but action.

How can we build an AI machine that acts on its own? First of all, it can’t be a conventional algorithmic computer program, but it must be a neural network. And it can’t be a neural network that we purposely train to serve our human purposes, but it must be a neural network that evolves by natural selection to pursue its own purposes.

In another comment, Lee Smolin asked, “Is there any concrete evidence for a programmable digital computer evolving the ability of taking initiatives or making choices which are not on a list of options programmed in by a human programmer?”

It sounds like Smolin is just waiting for it to happen, as if a computer can just start evolving all by itself. And that is never going to happen. In order for computer evolution to start, we need to set up the evolutionary environment in the computer circuits, and we need to spawn the first generation of neural network threads that will compete with each other.

So I’d like to rephrase Smolin’s question. Instead of asking whether it has happened, I would ask whether we have made it happen.


  1. Jeff says:

    The brain is not simply analog. The brain is both analog and digital. The neurotransmitters stimulating the dendrites of the neuron is certainly an analog process. However, the firing of the action potential along the axon is a purely digital process which leads to the release of neurotransmitters contributing to another analog process.

    An analog computer does not duplicate the process in the brain and neither does a digital computer.

    A limited self learning machine can be built, but duplicating the natural process of a brain, even an animal brain will occur by the techniques of molecular biology and genetic cloning, not by the wiring of electrical circuits together. Any attempt to duplicate the complicated biochemical and electrical activity of the brain with silicon and copper will fail.

    It would be far better to develop a direct interface between the computational and precision abilities of a digital CPU and the human brain.

    AI in a non biological system will never equal the abilities of the human brain. And pattern recognition is best left to humans, not machines.

  2. Mike says:

    I disagree. “the firing of the action potential along the axon is a purely digital process”. You are wrong on all points. The mind is akin to an analog process and there really is no digital aspect to it. You can emulate some of the processes in the human mind with a digital system. The process in the brain results in a concrete answer, and the digital system also gives you a concrete answer, but they arrive at the answer ( probably not the same one ) , in completely different ways. By the way any analog system will generate a result several orders of magnitude faster than a digital system. Understand that analog brains can approach a human-like thought process. The concentration has been on the digital mind and all of that is related to computation. The human mind does a lot less computation than people realize. Digital systems use computation and recall to create the illusion of thinking. Analog systems can actually think about things and consider things before making a decision. It’s mind blowing but true.