Tuesday, July 25, 2006

the brain is not a computer

Ray Kurweil argues that exponential growth will lead predictably to a singularity, when humans transcend biology, technological change so rapid and profound it represents a rupture in the fabric of human history (the law of accelerating returns)

Technology and science are developing at an exponential rate. If this sort of progress doubles its rate every year then in 25 years (2030) we will have enhancements in the order of 1 billion fold compared with now.

Energy is not a worry because nanotechnology combined with solar power will solve that problem.

People will live much longer and poverty and pollution will continue to decline.

In response, Rodney Brooks challenges the idea that exponential growth in itself will automatically produce the dramatic changes envisaged by Kurzweil.

For example, AI has been working on generic object recognition for 40 years but still can't do it.

We don't have a conceptual model of how the brain works. Theoretical, conceptual breakthroughs are required. Growth itself, even though exponential, is not sufficient.
A long time ago the brain was a hydrodynamic system. Then the brain became a steam engine. When I was a kid, the brain was a telephone switching network. Then it became a digital computer. And then the brain became a massively parallel digital computer. About two or three years ago I was giving a talk and someone got up in the audience and asked a question I'd been waiting for — he said, "but isn't the brain just like the World Wide Web?"

The brain is always — has always been — modeled after our most complex technology. We weren't right when we thought it was a steam engine. I suspect we're still not right in thinking of it in purely computational terms, because my gut feeling is there's going to be another way of talking about things which will subsume computation, but which will also subsume a lot of other physical stuff that happens.
- Rodney Brooks


Anonymous said...

Great post. This goes to an idea that I've been thinking about lately, how teachers' definitions of human being impact their decision making. I posted a commentary on an idea of Kurzweil's the other day.

This definitional tension is being forced by technology, which challenges us to reach consensus about who and what we are as ethical considerations demand political resolution. I agree with your "the brain is not a computer" statement and I think that we need to be careful about the metaphors we apply to ourselves. Computer science has embraced cognitivist notions of the brain as essentially computational, and many (or most??) people naively follow suit. I appreciate your efforts to throw light on the assumptions that play in the background.

Bill Kerr said...

I've been thinking about kurzweil for a while and your post was a catalyst for me to take another step.

I've bought a book by rodney brooks ("Flesh and Machines: How Robots Will Change Us")who has a different view of AI it seems.