Why do recent photographs show Bernard Madoff smiling? Why doesn’t he seem overwhelmed with guilt and shame – for hurting so many people and damaging so many meritorious institutions? For being a crook and a liar? A traitor to his fellow Jews and to his fellow human beings?

Confidence men like Madoff – they exist because of other people’s confidence in them – probably have a philosophy, a rationale: Never give a sucker an even break. Suckers supposedly deserve to be taken – because they are so greedy or because they’re so dumb and guileless.

What did Harry Lime (Orson Welles) say about the little dots (people) he could see from high up on a Ferris wheel in the film “The Third Man”? They look like ants. Why be concerned about them – why be concerned that the penicillin Lime was selling was ineffective?

Madoff might have been friendly with people who felt the same way: Never give a sucker an even break. I recall hearing an advertising man say that his ads were exaggerations (if not lies), but if people were stupid enough to believe them, that was their fault, not his. “You can’t cheat an honest man” – the title of another W.C. Fields film – means that the only people you can cheat are dishonest.

So much for the con artist’s philosophy. What about his or her motives?

Of course, some – to an extent – believe their own stories. (Snake oil, after all, sometimes actually works.) Still others might be adventurers, seeking excitement; others may turn to confidence games because it’s the only fairly decent money-making occupation open to them; and some fall in with other confidence people and assume that whatever their pals do is acceptable.

Besides which, it’s far easier to perpetrate a Ponzi scheme, as Madoff allegedly did – keep borrowing from Peter to pay Paul – than to actually make a regular profit in the investment markets.

A plausible possibility, of course, is that con artists have little or no conscience. Like Iago in Shakespeare’s “Othello,” they are guilty of “motiveless malignity.” In fact, Iago, according to a noted student of psychopaths, Robert Hare, “was a classic psychopath.” So, Hare argues, was Harry Lime. (Of course, Lime – while deficient of conscience – had as a motive a desire to make money.)

Conning other people, indeed, is considered a key marker for psychopathy. Hare, a Canadian psychologist, has created a 20-item Psychopathy Checklist, and among the markers is “conning.” Others include “parasitic lifestyle,” “pathological lying,” “proneness to boredom,” “shallow emotions,” and “lack of empathy.”

This information about psychopathy comes from an article by John Seabrook in the Nov. 10 issue of The New Yorker. That article also quotes an American psychiatrist, as having argued (back in 1941) that “the individualistic, winner-take-all aspect of American culture nurtures psychopathy.”

Psychopaths, in Hare’s view, can be found among lawyers, military men, politicians, and physicians. But the “most agreeable vocation” for psychopaths, he believes, is business. He has argued, in Seabrook’s summary, that “many traits that are desirable in a corporate context, such as ruthlessness, lack of a social conscience, and single-minded devotion to success, would be considered psychopathic outside of it.”

No one is sure what causes psychopathy. One hypothesis: For some reason or other, psychopaths don’t fear punishment. Indeed, whether or not psychopathy is even a mental disorder is unsettled.

The question of whether Madoff is actually a psychopath might receive some sort of answer if he were to take Hare’s 20-item Psychopathy Checklist. Meanwhile, it’s only an interesting possibility.

How to protect yourself against con artists?

Finley Peter Dunne (1867-1936), an American humorist, gave perhaps the best advice: Trust everyone, but cut the cards.