The Seen and the Unseen
The simple yet profound explanation of why people get themselves into serious epistemological trouble and propose idiotic policies and harebrained ideas is that they ignore the Law of Unintended Consequences. Often enough, when considering a given idea, proposal, option, or policy, people will focus only its beneficial consequences and ignore the negative or damaging ones, which may be further off in time and harder to foresee. But practically every human action entails a substantial network of consequences, and so a rational assessment of any proposal ought to take into account all of its effects, the obvious and the non-obvious, the intended and the unintended, not just those that immediately leap to the eye.
The core notion was captured most clearly by the French economist Frédéric Bastiat, who in 1850 wrote an essay called "That Which is Seen and That Which is Unseen." In it he describes a little boy's accidentally throwing a ball through a shopkeeper's window. Bystanders console the shopkeeper by telling him that, despite his loss, the accident will be a boon to the glazier, who will replace the window for six francs. (Today this is known as "job creation.")
True enough, the glazier benefits. "But," says Bastiat, "that is only what is seen. It is not seen that as our shopkeeper has spent six francs on one thing, he cannot spend them on another. It is not seen that if he had not had a window to replace, he would, perhaps, have replaced his old shoes, or added another book to his library. In short, he would have employed his six francs in some way, which this accident has prevented."
This so-called "parable of the broken window" has been exploited by free-market economists to oppose many ostensibly "humanitarian" government interventions that, they argue, have negative unintended consequences further down the line. Rent control, for example, while keeping some housing affordable is said to reduce the livability and availability of apartments that landlords can no longer afford to maintain.
But the lesson of the seen and the unseen is far more encompassing in scope than its applications within the dismal science. For example, species are sometimes introduced to ecological systems with a specific, narrow purpose in mind, whereas their actual introduction is accompanied by ripple effects that go well beyond the original purpose it was intended to serve. A well-known example is the importation and breeding of cane toads in Australia in order to control the cane beetle, a pest that ravaged sugar cane crops. But not only didn't they control the cane beetle, the toads themselves soon proliferated so wildly that they became major pests in their own right, and had the further effect of converting kindly, animal-loving citizens into raging maniacs on public roads and highways on which drivers, day and night, would swerve right and left in order to run over and flatten (with a loud "pop") as many of the monsters as came into view. (In addition, a group of otherwise sane golfers placed powerful lights on golf courses to attract the toads so that they could hit them with golf clubs and propel these amphibian golf balls across the fairways to their deaths, a scheme that in any case didn’t work: "Nine times out of ten the cane toad will get up and hop away," said one unamused critic of the practice.)
More recently, ethanol has been added to gasoline with the intention of reducing our dependence of foreign petroleum. That is what is seen. As for what is unseen, consider the set of ripple effects described by a team of energy specialists (in a 2007 piece actually entitled "The Ripple Effect: Biofuels, Food Security, and the Environment"). Since ethanol was made from corn, the increased demand for corn caused prices to rise (to wit, from $2.60 per bushel in July 2006 to $4.25 per bushel in March 2007). Higher corn prices in turn meant higher prices for corn-fed beef. It also meant that a basic food crop was made more expensive for food-insecure people who could least afford a price rise. Further ripple effects were massive increases in farmland values (making new acreage more dear to farmers), and greater use of artificial fertilizers, with increased runoffs and negative implications for nitrogen and phosphorous losses to groundwater, surface water, and the atmosphere. And so on.
Moral of the story: When entertaining the merits of some grand new miracle idea, look beyond the obvious.