Matthew Yglesias waxes rhapsodic about being on the “back half of the chessboard” in terms of the exponential growth of computer technologies.
The point of this, in terms of technological progress, is that we’ve gotten so accustomed to Moore’s Law that we sometimes overlook the implication that the deeper we get into the chessboard, the bigger the changes. We all know that computers advanced a lot between 1991 and 2011, but we should expect the scale of change over the next 20 years to dwarf those changes.
The “back half of the chessboard” is a reference to the old story about the inventor of chess. As the story goes, when chess was presented to a great king, the king offered the inventor any reward that he wanted. The inventor asked that a single grain of rice be placed on the first square of the chessboard. Then two grains on the second square, four grains on the third, and so on. Doubling each time.
The king, baffled by such a small price for a wonderful game, immediately agreed, and ordered the treasurer to pay the agreed upon sum. A week later, the inventor went before the king and asked why he had not received his reward. The king, outraged that the treasurer had disobeyed him, immediately summoned him and demanded to know why the inventor had not been paid. The treasurer explained that the sum could not be paid – by the time you got even halfway through the chessboard, the amount of grain required was more than the entire kingdom possessed.
The king took in this information and thought for a while. Then he did the only rational thing a king could do in those circumstances. He had the inventor killed, as an object lesson in the perils of trying to outwit the king.
For the most part, this fable is used as a lesson in the power of exponential growth. From the one grain of rice on the first square of the chessboard, the amount increases to the point that by the time you get to square 64, there are over 18 quintillion grains of rice on the board. In mathematics, it’s a demonstration of extreme growth.
But in the real world, this story teaches a different lesson, and that lesson is this: exponential growth cannot be sustained. The inventor can’t be paid because well before you get to the end of the chessboard, you run out of grain! You’ve hit the physical limitations of the math, and as a consequence, the growth either leads to a dramatic downturn (as in a Malthusian system), or it simply levels off.
The same thing applies to technology. Very often, at the extreme ends of cutting edge research, you can see a dramatic increase of capabilities of a new technology very quickly – even over the course of decades. For example, take air travel. Before 1900, heavier-than-air flight hadn’t even been invented yet!
But once flight had been invented, a race began to see who could break the next air speed record. Airplane development, especially in the military, focused on making faster and faster planes. Take a look at the chart I made out of the air speed records below:
As you can see, at the beginning of flight, you see nice, linear growth in airspeeds. Then in the 50′s, the curve turns exponential. But then, as you get near the end of the 1960s, it levels off, and the airspeed record reached its pinnacle in 1976.
You read that right. The air speed record, made by the SR-71 Blackbird, has been unbroken for thirty-five years.
Why? Because at that point, you hit the physical limitations of airflight. It just became impractical to make a plane that could go any faster. That doesn’t mean that air travel hasn’t changed the world – it definitely has! Air travel has made it much more convenient and faster to travel, and people now travel more than they ever did. But they don’t travel at Blackbird speeds or even close to Blackbird speeds. It isn’t practical to do so. It uses too much fuel and eventually the plane can’t hold enough passengers to make it worthwhile. There aren’t even any commerical supersonic planes anymore now that the Concorde has been decommissioned.
You can even, to a certain extent, see this happening with information technologies. People like to say that the computer in their smartphones is faster than the giant one that guided the Apollo missions. That’s true. But it’s also much weaker and less capable than the computers most of us had on our desktops a half-decade ago. At the outer ends of performance and supercomputing, speed of computing is still moving at a breakneck speed. But in our day to day lives, it isn’t.
In point of fact, in our everyday lives, the trend isn’t towards faster computing – it’s towards mobile computing. That’s a different proposition altogether. I’m writing this post right here on a new laptop that isn’t as powerful as the budget, bare bones desktop I built for myself a year and a half ago. And that bare bones desktop rarely, if ever, uses more than half of its resources at a given time – and even then, that’s when I’m playing games.
For most of us, computing is simple: we want to surf the web, stream video, listen to music, play games, talk on Skype, and post on Facebook. For professionals, we might want to do a spreadsheet, some word processing, and write emails. The computing we have now is more than equal to those tasks – which is why those relatively weak smartphones and tablets can still amaze, even though we technically had better computers before.
But even with speeds getting faster on the margins, the fact of the matter is, eventually, Moore’s Law will end (indeed, some argue that it already has). Computing speeds will start to level off, and development will focus ever more on the refinement of capabilities and meeting human needs. In most of our day to day lives, the computers we use aren’t going to get exponentially faster – because they don’t have to.
That doesn’t mean that we won’t see remarkable innovation, or that computing technology won’t continue to change our lives. It definitely will. I’d say we probably have a long way to go to simply meeting the potential for computing that we have available to us now.
The bottom line, though, is that the day will come that the fastest computers start to slow down. It might be in a decade, it might be in half a century. But it will happen, because exponential growth in anything simply cannot continue indefinitely.
Eventually, you run out of rice.