Written by Kevin Drum on Mother Jones.
One statistic on this little piece right here caught my eye and made me wonder where the original source for it came from (the one about Lake Michigan having roughly as many fluid ounces of water as calculations in the human brain). So I snooped around and found this and
Suppose it's 1940 and Lake Michigan has (somehow) been emptied. Your job is to fill it up using the following rule: To start off, you can add one fluid ounce of water to the lake bed. Eighteen months later, you can add two. In another 18 months, you can add four ounces. And so on. Obviously this is going to take a while.
By 1950, you have added around a gallon of water. But you keep soldiering on. By 1960, you have a bit more than 150 gallons. By 1970, you have 16,000 gallons, about as much as an average suburban swimming pool.
At this point it's been 30 years, and even though 16,000 gallons is a fair amount of water, it's nothing compared to the size of Lake Michigan. To the naked eye you've made no progress at all.
So let's skip all the way ahead to 2000. Still nothing. You have—maybe—a slight sheen on the lake floor. How about 2010? You have a few inches of water here and there. This is ridiculous. It's now been 70 years and you still don't have enough water to float a goldfish. Surely this task is futile?
But wait. Just as you're about to give up, things suddenly change. By 2020, you have about 40 feet of water. And by 2025 you're done. After 70 years you had nothing. Fifteen years later, the job was finished.
IF YOU HAVE ANY KIND OF BACKGROUND in computers, you've already figured out that I didn't pick these numbers out of a hat. I started in 1940 because that's about when the first programmable computer was invented. I chose a doubling time of 18 months because of a cornerstone of computer history called Moore's Law, which famously estimates that computing power doubles approximately every 18 months. And I chose Lake Michigan because its size, in fluid ounces, is roughly the same as the computing power of the human brain measured in calculations per second.
In other words, just as it took us until 2025 to fill up Lake Michigan, the simple exponential curve of Moore's Law suggests it's going to take us until 2025 to build a computer with the processing power of the human brain. And it's going to happen the same way: For the first 70 years, it will seem as if nothing is happening, even though we're doubling our progress every 18 months. Then, in the final 15 years, seemingly out of nowhere, we'll finish the job.
And that's exactly where we are. We've moved from computers with a trillionth of the power of a human brain to computers with a billionth of the power. Then a millionth. And now a thousandth. Along the way, computers progressed from ballistics to accounting to word processing to speech recognition, and none of that really seemed like progress toward artificial intelligence. That's because even a thousandth of the power of a human brain is—let's be honest—a bit of a joke. Sure, it's a billion times more than the first computer had, but it's still not much more than the computing power of a hamster.
Y'know... this explains a lot.