Unlike a machine, an economy was neither designed by anyone nor built in a factory. There are no plans… no owner’s manual… no guide to troubleshooting problems… and no website where owners go to talk about the problems they’ve had and the tricks they’ve used to fix them.
Not made by man… it cannot be repaired by man. But let’s look at why this is so.
First, an economy is a “complex adaptive system.” It has lots of moving parts, in other words, and each of these parts has information and desires of its own.
The farmer in Mississippi may know that his bottom 40 acres are too wet to plow. The Department of Agriculture has no idea. The plumber in Milwaukee may know that his business is slowing down. But how would Krugman know?
What machine has intelligent parts… each responding to its own information base, more or less independently?
Second… and perhaps more importantly… the parts have desires of their own. You build a machine to accomplish the desires of the designer. An economy, on the other hand, is merely a way for the constituent parts to achieve their own ends.
Imagine an automobile that goes where the steering wheel wants to go! Imagine a motor that runs faster when the carburetor feels frisky… and slows down when the valves get tired.
You can see that this is like no machine ever created. The parts want to go in different directions… at different speeds… for different reasons. The economy is much more like a flock of birds than a Boeing 747.
There’s more at the link. Highly recommended reading.