marvel that the high priest of free-market capitalism, once a disciple of the radically unsentimental libertarian Ayn Rand, should be talking not just about “corporate-governance checks and balances” but about a deadly sin. The last time Greenspan nailed a cultural mood with a pointed phrase–“irrational exuberance”–he was warning against a tulip craze; it didn’t even amount to a venial sin. Now, as that word “infectious” suggests, he was diagnosing a terminal spiritual disease.

Just months ago, before the wave of corporate scandals, what’s now called greed was called enterprise, ambition, savvy or gumption. By the end of last week, when the stock market dropped like an elevator vetted by a bribed building inspector, nobody needed to hear strictures against greed anymore. (Their own greed, that is. Other people’s greed? Lock ’em up.) Greenspan was delivering a temperance lecture to an audience hugging the toilet. For some executives, the problem had suddenly changed from whether to build that third home in Aspen or Aruba to whether they’d end up in bankruptcy or the slammer. (For congressmen with wetted fingers in the wind, the answer was, why not both?) Greed–whose etymology suggests literal hunger–is a craving, by its very nature insatiable, for more than you need. You can be greedy only when you’re already sitting pretty.

But to fix the boundary between greed and honest sufficiency is as hard as driving a Lincoln Navigator through the eye of a needle. Aquinas said greed was “a sin directly against one’s neighbor, since one man cannot over-abound in external riches, without another man lacking them.” (Of course, this was when we thought economics was a zero-sum game, before the rising tide postulated by the trickle-down theory lifted all boats, especially 200-foot yachts.) The unworldly would argue that since the average annual pay in the United States in 2000 (the latest available figure) was around $35,000, even folks making $70,000 ought to be ashamed of themselves. But if greed is a perversion of the wired-in human impulse toward self-protection–gathering and hoarding against hard times to come–where, exactly, does it cross the line? If you’d been an Enron worker bee, wouldn’t you have tried to pump up your 401(k) with inflated company stock? Everyone around you was doing it; too soon they’d be bidding up the cost of a decent retirement. If you’d been WorldCom CEO Bernie Ebbers, with the well-being of thousands of employees and millions of customers in your hands, would the $11.1 million you made in 2000 seem like enough when A-Rod was making $25.2 million playing shortstop for the Texas Rangers? It’s the nature of addiction to sneak up on you in apparently harmless increments: during the initial stages, life would be about right if you could just add on that two-car garage. Toward the middle, it seems a little hard if you can’t have a Lexus and a Boxster in it. Near the end you’ve got a Learjet and life is still intolerable.

Here’s a story about greed from one of those past generations Greenspan mentioned–about its insidious seductiveness, its insatiability, its ultimate pointlessness. In Tolstoy’s parable “How Much Land Does a Man Need?” a peasant named Pahom thinks, “If I had plenty of land, I shouldn’t fear the Devil himself.” The Devil, sitting hidden behind the stove, grants his wish. Pahom scrapes together enough money to buy 40 acres, and is content for a while. But his landless neighbors begin trespassing, and after quarrels and legal cases, he moves away and buys 125 acres–which still turns out to be insufficent. Then he hears about a far-off territory where the locals have more virgin land than they know what to do with. They offer him a bargain price for as much land as he can circumambulate in a day, and he walks on and on, taking in more and more rich grasslands and damp, fertile hollows. But he goes too far, exhausts himself getting back and collapses, dead, at his starting point. You already know the ending: “Six feet from his head to his heels was all he needed.” If the avenues to express greed have grown twistier–from raising corn, cattle and flax to manipulating virtual information about imaginary money–they lead to just the same place.