When I was a kid, I loved watching “Happy Days,” even at its shark jumpiest. A big part of the appeal was the adolescent power fantasy of Arthur Fonzarelli, a disco-era caricature of a 1950s motorcycle hoodlum-with-a-heart-of-gold. As the series progressed, Fonzie developed an almost mystical aura, becoming somebody who could make almost anything happen through the sheer power of his cool.

The Fonz could knock down doors with a slap of his hand, summon any girl with a snap, and most often on the show displayed his classic power of fixing the jukebox by banging on it. It’s a seductive fantasy that one might be able to fix a complex piece of machinery through an application of blunt force, without having to worry about the intricate mechanisms that actually allow the machine to work.

Unfortunately, this is the mentality that has reigned for decades in applied public policy.

Is the economy broken? Bang on it. That’ll get it chugging along again. Wait, that didn’t work? You didn’t bang it hard enough. Or maybe your leather jacket needs to be a little cooler next time. At any rate, it’s your fault. If you’d only smacked the economy the way that Fonzie showed you, it totally would have worked.

Economic prescriptions thereby stem from a non-falsifiable tenet of faith in a grown-up power fantasy.

This kind of magical thinking convinces many because it is accompanied by a veneer of rigorous thought. There are even equations! Surely, equations are scientific! But as economist Don Boudreaux pointed out at Cafe Hayek:

The ability to write letters on a board in the form of an equation, to give those letters names that seem to correspond to some imaginable economic things, and to assemble quantitative data on those things, is not necessarily good science.

Keynesian macroeconomic variables lump heterogeneous goods and services into undifferentiated masses, no longer to be understood as the complex workings of a dynamic system of social cooperation. But just because you can gather a bunch of statistics and aggregate them into a variable doesn’t mean that the variable has a meaningful application to the real economy.

If you want to fix a jukebox in real life, a mechanic might be able to get the job done by tinkering with the machinery until each piece once again functions correctly. It’s easy for people who have a facility with physical forms of engineering to take a similar view of the economy, thinking that if only the right people were in charge, they could tweak policy here and there to ensure successful outcomes for everyone. Adam Smith explained why the economy can’t be successfully engineered in such a way:

The man of system, on the contrary, is apt to be very wise in his own conceit; and is often so enamoured with the supposed beauty of his own ideal plan of government, that he cannot suffer the smallest deviation from any part of it. He goes on to establish it completely and in all its parts, without any regard either to the great interests, or to the strong prejudices which may oppose it. He seems to imagine that he can arrange the different members of a great society with as much ease as the hand arranges the different pieces upon a chess-board. He does not consider that the pieces upon the chess-board have no other principle of motion besides that which the hand impresses upon them; but that, in the great chess-board of human society, every single piece has a principle of motion of its own, altogether different from that which the legislature might chuse to impress upon it. If those two principles coincide and act in the same direction, the game of human society will go on easily and harmoniously, and is very likely to be happy and successful. If they are opposite or different, the game will go on miserably, and the society must be at all times in the highest degree of disorder.

Even though an economy can’t be planned, or even tailored, successfully from on high, that form of scientism is at least understandable. It at least takes into account a small measure of the complexity of decentralized economic activity, even if it doesn’t — indeed, can’t — consider the rest. Keynesian macroeconomics is far worse, shunning even the scientistic attempt to grapple with at least some heterogeneous microeconomic factors as being the causal source of economywide trends. Instead, they insist that policymakers expropriate as much cash as humanly possible and wallop the economy with it as hard as they can.

Economist Steven Horwitz summed up the real prescription for economic recovery:

Being too focused on Keynes’s aggregates can also mislead us as to the best ways to get out of the recession once we’re in it. It may look as if all we need more is investment or more jobs. But once we understand that the “fundamental mechanisms of change” have to do with the boom’s microeconomic misallocation of capital and labor, we see that what is needed is a reallocation of resources not just more of them. Capital needs to move out of unproductive lines and back toward productive ones, and the same is true of labor.

Stimulus spending, bailouts, and extension of unemployment benefits only prevent the fundamental mechanisms of change from doing their work in unwinding the errors of the last decade. The cure for macroeconomic discoordination is freeing up the entrepreneurial market process to reallocate and coordinate resources. But 80 years after Hayek first made the point, the fascination by economists and politicians with Keynes’s aggregates continues to conceal the fundamental mechanisms of change, and in so doing, also continues to block the processes through which a sustainable recovery can take place.

In the end, the economy is not a jukebox, and neither a mechanic nor Ben Bernanke in the coolest leather jacket ever made can save it from its turmoils. Instead, the economy is made up of hundreds of millions of people with billions of plans, many of which fail but some of which succeed. Nobody knows for sure which plans will pan out in advance — not the people making them, and certainly not their public officials.

Only by letting individuals, alone or in voluntary association with others, respond to local conditions with unique knowledge can the best plans be discovered, expanded, and replicated. That process is made much more difficult when they face continual interference from central planners who only pretend they can know what’s best.

[Cross-posted at Shrubbloggers.]