To know the future with certainty is the most ardent desire of humankind. It’s terrifying to think the future isn’t knowable, and so we do what we can to reduce the fear. The problem these days is that fewer and fewer people can stake a believable claim to being a soothsayer. And we have grown terribly dependent on those who speak and write with absolute assurance about where we’re going.

The questions that most of us who write about politics and policy are asked more than any other begin with the words: “What do you think is going to happen with . . .” You can fill in the rest: the health-care bill, or the 2010 election, or cap-and-trade. What our interlocutors want from us is confidence, assurance; they think that since we do this sort of thing for a living, we can offer them an anchor in unsteady waters. That may be truer than ever today, even though the record of the recent past should teach us all that prognosticators are not to be trusted.

I know someone who has been an intimate adviser to elected officials at all levels, offering advice and counsel about what to do. He does what he does armed with all manner of facts and data. He’s very, very brilliant. The problem is that half of what he predicts comes to pass and half turns out to be laughable; the same is true of the solutions he proposes. But it’s not his track record that seduces the politicians who come to rely on him. It’s his certainty.

Over the past 15 months, people who had spent the previous 25 years riding the wave of an economy that tripled in size and a stock market that rose nearly 18-fold have lost confidence in their own judgment. They confess they are at a loss to understand what the true condition of the economy is and the direction in which it will go. Perhaps the massive stimulus will continue to keep things afloat through 2010 until the private sector can make its way back; perhaps we are in for a second dip into recession; perhaps we are in for a very long period of very slow growth. And so they smile ruefully, hedge their bets, and look for cheap deals.

Back in the 1980s, the screenwriter William Goldman revolutionized the discussion of the motion-picture business when he observed that studio executives never had the foggiest idea which films would hit and which would miss. Goldman’s three-word formula was astonishingly simple: “Nobody knows anything.” This is the abashed mood of the nation, and it seems entirely appropriate.

The only people in America who are moving ahead heedlessly and without regard to the terrible economic uncertainty that has gripped us are the leaders of the Obama administration and their acolytes. Throughout 2009, they have moved relentlessly, accumulating unprecedented levels of public debt, nationalizing the auto industry, setting salary levels at banks, and pushing a health-care package that will require the imposition of huge tax increases on the middle class.

Before the economic meltdown, only the most radically minded leftist would have believed that a severe downturn was the proper moment to be forcing through a cascade of new imposts, onerous regulations, and a massive increase in the size of the public sector. Had Barack Obama inherited a booming economy, his effort to push one or two of these major changes in the relation between the citizenry and the government could have been easily defended as an appropriate use of national wealth. But all of them at once? He would have been criticized, properly, and by some members of his own party, for endangering the nation’s prosperity.

Now that America seems less prosperous, it is even more astonishing that this should be the course Obama has set. His unlikely rise to the presidency is an example of the validity of the “nobody knows anything” theory. He should have heeded it instead of giving in to a false certainty that might threaten the nation’s future and imperil his own.