THE WORLD AS I FOUND IT By Bruce Duffy Ticknor & Fields. 546 pp. $19.95 SAINTS AND SCHOLARS By Terry Eagleton Verso. 145 pp. $14.95

BRUCE DUFFY, a 34-year-old writer from Takoma Park, and Terry Eagleton, England's best-known Marxist literary critic, are both first novelists, but neither is the first to recognize that Ludwig Wittgenstein -- the giant of 20th-century philosophy and the central figure in both Duffy's The World As I Found It and Eagleton's Saints and Scholars -- pursued truth a little too colorfully to be left on the non-fiction shelves.

Iris Murdoch's first novel, Under the Net (1954), featured a barely disguised portrait of him in Dave Gellmann, anti-metaphysician. Austrian writer Thomas Bernhard retooled Wittgenstein as a suicidal mathematician in his novel, Correction (1975). Randall Collins, in The Case of the Philosopher's Ring (1978), dispatched Sherlock Holmes to probe the theft of Wittgenstein's brain.

The man plainly attracts novelists like fleas. And the reason is simple -- he was a walking soap opera.

Born in 1889 in Vienna, the son of steel magnate Karl Wittgenstein, Wittgenstein bounced on Brahms' knee as a child. As a young man, his brilliance in logic led him to study with Bertrand Russell in Cambridge, where Russell called him "the most perfect example I have ever known of genius as traditionally conceived."

Wittgenstein's ideas about language's link to the world seemed to jibe with Russell's, and Russell tried to make him a disciple. But Wittgenstein resisted. Haughty, eccentric and obsessive, he clashed with both Russell and G.E. Moore, both of whom believed that philosophical work should end at 5 p.m.

Indeed, Wittgenstein's personal life teemed with unconventionality. Three of his brothers committed suicide, and Wittgenstein often threatened the same. He renounced his fortune and lived in Spartan lodgings. He disparaged philosophy and urged admirers to leave it. According to one controversial biography, W.W. Bartley III's Wittgenstein, he was a self-loathing homosexual, given to bouts of promiscuous cruising that revolted him.

During World War I, he fought in the Austrian Army and wrote the only book published in his lifetime, the Tractatus. After the war, he decided to teach elementary school in Austrian villages. In 1929, however, he returned to Cambridge. The so-called "later Wittgenstein" rejected the "early" one's theories, writing that all philosophers could do was identify "bumps" that the understanding suffers by "running its head up against the limits of language." He died in 1951, hugely influential.

DUFFY'S ambitious approach fully exploits the known facts on Wittgenstein, Russell and Moore, imagining anything necessary to fill in the gaps. The World As I Found It should be welcomed as manna by many readers starved for intellectual content in their fiction. But a book that strives as hard as Duffy's to be literature also asks to be judged by high standards. Here, alas, it fails.

Because Duffy regularly bloats his story with the beliefs and histories of minor characters, the book lacks "the severe criteria of harmonious balance" that Duffy recognizes in Wittgenstein's own work. The World As I Found It pans from Wittgenstein to Russell to Ottoline Morrell (Russell's mistress) to David Pinsent (Wittgenstein's friend) to Pinsent's mother to D.H. Lawrence to Dora Russell to Russell's mistresses and even, most ludicrously, to the dog at Russell's school, Beacon Hill.

Duffy, in short, can't seem to decide where he wants to go with his material. The novelist who chooses a great thinker as his protagonist usually has a tool for a client -- we expect an ulterior message. Duffy's is unclear.

An even more damaging misstep is Duffy's wordiness, deeply antithetical to the elegant styles of his three philosophical stars. At one point, Duffy's Moore tells Wittgenstein, apropos of the Tractatus, that "it seems as if it was painful for you to say even one word more than was necessary to express your meaning." Duffy, instead, regularly wallows in poetic overkill while straining after epiphanies: "Now the picture of his life cast its shadow across the world. Bitterly, he thought of how fiercely he had fought to save himself. And for what? Flatulent heart. Fraudulent life. The shadow ran through a sieve, spilling lies in the vain hope of distilling even a few grains of truth."

Elsewhere, when not dyeing his thinkers purple, Duffy encases them in prosaic packages. Typical is this size-up of Wittgenstein: "The irony was that he was at the height of his intellectual powers and he knew it, which should have been liberating but was instead a sorrow, when he saw how little had been achieved for all his efforts." The man who asked what is left when we "subtract the fact that my arm goes up from the fact that I raise my arm," did not think in such cliche's.

Eagleton's short, funny Saints and Scholars is more of a romp. The author chooses an Irish cottage in the year 1916 as the setting for his sitcom. To it, he efficiently lures an unlikely crew: Irish revoltionary leader James Connolly, Wittgenstein, Nikolai Bakhtin (brother of Mikhail, the Marxist esthetician) and Leopold Bloom, on the lam from Ulysses.

Like Duffy, Eagleton takes famous Wittgensteinian phrases and inserts them into dialogue, paying even less mind to historical accuracy. But perhaps because Eagleton knows the chief rule of Oxbridge intellectual debate -- be quick, lucid, witty and gone -- he manages two feats Duffy never quite brings off: recreating the feel of combat among first-class intellectuals and insinuating a philosophy of his own.

Harsh yet clever descriptions of life in Dublin, Vienna and St. Petersburg score Eagleton's ideological points for him. Yet, as a believer in Mikhail Bakhtin's theory that a bit of "carnival" should both lighten and undercut egghead argument, Eagleton injects moments of farce while still conducting a spirited debate on revolution, language, nationalism, philosophy and English tastes.

WHEN SOLDIERS come looking for Connolly, Wittgenstein is hilariously certain that they're Cambridge agents sent to drag him back so they can steal more ideas. At the same time, sharp debate on issues is admirably condensed: "While the revolutionary leaders speak of crisis," said Wittgenstein, "everything for the common people carries on just as it was."

"The fact that everything carries on just as it was," replied Connolly, "is the crisis."

Unlike Duffy, Eagleton boldly crystalizes. He nicely summarizes Wittgenstein's epistemology -- "knowledge was more know-how than know-why" -- while unleashing the others to challenge it, as when Bloom declares, "Philosophy's just a fancy name for not caring about people." The payoff is Tom Stoppard with a Marxist soundtrack.

On the whole, Eagleton keeps in mind what Duffy allows to lapse -- that great philosophers are capable of sustained philosophical conversation. Duffy tends to Americanize his leading men, presenting each as if he had a 30-second attention span for philosophy and was wholly the product of his libido. Wittgenstein is Bartley's tormented homosexual. Russell is a rake so incorrigible he can't concentrate on logic even during Wittgenstein's doctoral exam. Moore hardly has a thought beyond food and marriage.

As a result, they neither ring true nor entertainingly false. Explaining an intellectual's vision by his personality or childhood is, admittedly, the safe approach after Freud. Yet much evidence about Russell, Wittgenstein and Moore suggests that they constructed their mature personalities to conform with their philosophies.

Now there's a challenging novel. Duffy hasn't written it. Eagleton, at least, permits its possibility.

In one of Duffy's recreated letters, Russell writes to Ottoline, "Wittgenstein does so appeal to me -- the artist in intellect is so very rare."

True.

Carlin Romano is the literary editor of The Philadelphia Inquirer.