On Mon, Sep 3, 2012 at 5:58 PM, Ivan Vodišek <
ivanv...@gmail.com> wrote:
> I think that human kind can do everything they can imagine.
I didn't say that AGI is impossible. I said that we aren't going to be
the ones to build it.
The value of making machines smart enough to do all the work that
people can do is equal to the world GDP ($70 trillion) divided by
market interest rates. That is about US $1 quadrillion. Don't you
think that other people have been working on this? Already, a lot of
the simpler work has been automated.
People that think there is a simple solution to AGI haven't done a
cost estimate. The best known solutions to hard problems like
language, vision, and robotics use neural networks. A human brain
sized neural network has 10^15 connections and runs at 10 Hz. A
computer simulation requires 10 petaflops and 1 petabyte. Such
computers exist. They fill a large building and use 10 MW of power. If
you wait about 25 years, Moore's Law should bring the cost down to
make it competitive with human labor and we can build several billion
of them to automate the labor force.
There is also software. The human brain is complex. Evolution has
programmed in a lot of optimizations and hacks, hard coding lots of
specific functions like the sneeze reflex, fear of heights and
spiders, and an unknown algorithm for recognizing humor and good music
that you would need to replicate if you want to automate the
entertainment industry along with the rest of the economy. The
complexity is upper bounded by the information content of your DNA,
which is at most 6 x 10^9 bits. An equivalent program is about 10M
lines of code, which would cost about $1 billion at $100 per line. But
you only have to write it once and make lots of copies. Well, almost,
because humans are not genetically identical. It takes about 1000 bits
to describe your DNA given your parent's DNA, due mostly to mutations.
Assuming 100 bits per line of code, then you need 100B lines to
describe the diversity of human brains, or $10 trillion.
But whether it's $1 billion or $10 trillion I don't care, because
either way it is insignificant compared to the cost of hardware and
human knowledge collection. Knowledge will be the most expensive
component once the hardware becomes affordable. People communicate
successfully with other people because they can guess what the other
person knows and how they will act. The reason computers don't
understand us is because they don't have models of our minds like we
do of other people. A model of a mind is a function that takes sensory
input and returns a prediction of your actions. With a model of you, I
could predict what would make you happy, or what would make you buy
something. If I programmed a robot to carry out those predictions in
real time, then I would have an upload of you. Already, companies like
Google and Facebook are building crude models of your mind every time
you write a message. They use these models to predict which emails or
posts or ads are likely to interest you and which ones to block, and
increasingly to understand our messages and respond intelligently.
We can estimate the cost of acquiring this knowledge. According to
Landauer (
http://csjarchive.cogsci.rpi.edu/1986v10/i04/p0477p0493/MAIN.PDF
) human long term memory capacity is 10^9 bits. About 99% of this
knowledge is written down or is known to other people. I estimate this
percentage based on the U.S. Dept of Labor's estimate that it costs 1%
of lifetime earnings to replace an employee. This leaves 10^7 bits
known only to you. It can only be learned through human communication
channels like speech, writing, or typing, which have a rate of about 2
to 5 bits per second each way over a 2 way channel. Human time is
worth about $5 per hour, assuming global per capita income of $10K and
2000 hours per year. Thus, it costs $10K per person, or $100 trillion
for the world population of 10 billion that is likely in 25 years.
That cost will rise as the economy grows and wages go up.
Clearly, AGI will require years of global effort. So we need to think
hard about what we actually plan to build.
-- Matt Mahoney,
mattma...@gmail.com