For decades the German philosopher Martin Heidegger  has been the subject of passionate debate. His critique of Western thought and technology has penetrated deeply into architecture, psychology and literary theory and inspired some of the most influential intellectual movements of the 20th century. Yet he was also a fervent Nazi.
Now a soon-to-be published book in English has revived the long-running debate about whether the man can be separated from his philosophy. Drawing on new evidence, the author, Emmanuel Faye, argues fascist and racist ideas are so woven into the fabric of Heidegger's theories that they no longer deserve to be called philosophy. As a result Mr. Faye declares, Heidegger's works and the many fields built on them need to be re-examined lest they spread sinister ideas as dangerous to modern thought as "the Nazi movement was to the physical existence of the exterminated peoples."
First published in France in 2005, the book, "Heidegger: The Introduction of Nazism Into Philosophy," calls on philosophy professors to treat Heidegger's writings like hate speech. Libraries, too, should stop classifying Heidegger's collected works (which have been sanitized and abridged by his family) as philosophy and instead include them under the history of Nazism. These measures would function as a warning label, like a skull-and-crossbones on a bottle of poison, to prevent the careless spread of his most odious ideas, which Mr. Faye lists as the exaltation of the state over the individual, the impossibility of morality, anti-humanism and racial purity.
The book is the most radical attack yet on Heidegger (1889-1976) and would upend the philosophical field's treatment of his work in the United States, and even more so in France, where Heidegger has frequently been required reading for an advanced degree. Mr. Faye, an associate professor at the University of Paris, Nanterre, not only wants to drum Heidegger from the ranks of philosophers, he wants to challenge his colleagues to rethink the very purpose of philosophy and its relationship to ethics.
At the same time scholars in disciplines as far flung as poetry and psychoanalysis would be obliged to reconsider their use of Heidegger's ideas. Although Mr. Faye talks about the close connection between Heidegger and current right-wing extremist politics, left-wing intellectuals have more frequently been inspired by his ideas. Existentialism and postmodernism as well as attendant attacks on colonialism, atomic weapons, ecological ruin and universal notions of morality are all based on his critique of the Western cultural tradition and reason.
Richard Wolin, the author of several books on Heidegger and a close reader of the Faye book, said he is not convinced Heidegger's thought is as thoroughly tainted by Nazism as Mr. Faye argues. Nonetheless he recognizes how far Heidegger's ideas have spilled into the larger culture.
"I'm not by any means dismissing any of these fields because of Heidegger's influence," he wrote in an e-mail message referring to postmodernism's influence across the academy. "I'm merely saying that we should know more about the ideological residues and connotations of a thinker like Heidegger before we accept his discourse ready-made or naïvely."
Although the English text published by Yale University Press won't be out in the United States for a few weeks, it is already making waves, as signaled by an essay in The Chronicle Review, the opinion and ideas journal of The Chronicle of Higher Education. In an essay titled "Heil Heidegger!" Carlin Romano, a critic for The Review, called Heidegger a "Black Forest babbler" and fraud who was "overrated in his prime" and "bizarrely venerated by acolytes even now."
Few people have read the book, but the article has generated more than 150 online comments from vehement advocates and detractors, more than any other piece The Review has printed this year, said Liz McMillen, the editor. Others joined the fray.
Ron Rosenbaum, the author of "Explaining Hitler ," even extended the argument to the German Jewish philosopher Hannah Arendt, a former student and lover of Heidegger's. Citing a recent essay by the historian Bernard Wasserstein, Mr. Rosenbaum wrote in Slate.com  that Arendt's thinking about the Holocaust and her famous formulation, "the banality of evil," were contaminated by Heidegger and other anti-Semitic writings.
Commentators heatedly rejected the notion that significant ideas could not be distilled from vile ones. Writing for The New Republic's Web site, tnr.com , Damon Linker declared it was "absurd" to "implicate Heidegger's entire philosophical corpus."
He and others echoed the views of the influential American philosopher Richard Rorty, who once wrote in The New York Times, "You cannot read most of the important philosophers of recent times without taking Heidegger's thought into account." Mr. Rorty added, however, that "the smell of smoke from the crematories" will "linger on their pages."
In Mr. Faye's eyes Heidegger's philosophy cannot be separated from his politics in the way, say, T.S. Eliot 's poetic skills or D. W. Griffith's cinematic technique might be appraised independently of his own beliefs. While he doesn't dispute Heidegger's place in the intellectual pantheon, Mr. Faye reviews his unpublished lectures and concludes his philosophy was based on the same ideas as National Socialism.
Without understanding the soil in which Heidegger's philosophy is rooted, Mr. Faye argues, people may not realize that his ideas can grow in troubling directions. Heidegger's dictum to be authentic and free oneself from conventional restraints, for example, can lead to a rejection of morality. The denunciation of reason and soulless modernism can devolve into crude anti-intellectualism and the glorification of "blood and soil."
Passions about Heidegger have simmered for years. He joined the Nazi party in 1933 when he became rector of Freiburg University and oversaw the dismissal of all Jewish professors. After the war Heidegger was banned by a de-Nazification tribunal from teaching. In the 1950s Arendt re-established ties with him and labored to revive his reputation.
Heidegger was a critic of modern technological society and of the Western philosophical tradition that gave rise to it. He argued that we must overcome this tradition and rethink the very nature of human existence or being.
His prose is so dense that some scholars have said it could be interpreted to mean anything, while others have dismissed it altogether as gibberish. He is nonetheless widely considered to be one of the century's greatest and most influential thinkers.
Theologians have used his critique of reason to explain the leap of faith; architects have been inspired by his rejection of conventional rules to introduce a buffet of new styles, materials and shapes to building design. His criticism of mechanistic technology has attracted environmentalists and planners.
A verbal brawl over Heidegger's theories should not be surprising, though. After all, the classic American position on how liberal societies should treat dangerous ideas is worth more discussion.
That is precisely what Mr. Faye says he wants. In his view teaching Heidegger's ideas without disclosing his deep Nazi sympathies is like showing a child a brilliant fireworks display without warning that an ignited rocket can also blow up in someone's face.