Every few decades, writes Adam Kirsch, the fact that Martin Heidegger was enthusiastic about Nazism—and not just “an unworldly man who briefly blundered into it”—seems to be rediscovered, and promptly forgotten again. The latest rediscovery has come with the publication of the philosopher’s Black Notebooks, now partially available in English, as well as a volume of scholarly essays about them. Based on the former, Kirsch expounds on the connection between Heidegger’s rejection of ethics and his embrace of the Third Reich:

Of course, Heidegger’s thought does not lead directly to fascism. . . . But in an important sense, Heidegger leaves the door open for fascism, because he values the intensity and authenticity of a belief over its goodness or truthfulness. In a world defined by nihilism, any source of strong new beliefs and convictions is potentially redemptive. That is why, in the early days of the Hitler dictatorship, Heidegger could take the new Nazi regime as a potential source of new values—an assertion of will that would create an entirely new spiritual and philosophical world.

Nonetheless, admirers of Heidegger persist in finding reasons to ignore his inconvenient beliefs. Now that the Black Notebooks, which contain explicit references to Jews, make his anti-Semitism undeniable, apologists assert, correctly, that Heidegger disavowed any condemnation of Jews based on their biological race:

But this is hardly exculpatory. On the contrary, [Heidegger’s comments on Jews] bring anti-Semitism into the central precincts of his thought. For Heidegger, the “uprooting of beings from Being,” [which he blames on the Jews], was the metaphysical curse of the modern world, the source of the nihilism that afflicted humanity. . . .

Heidegger is a writer who cultivates a mystique of complexity; this is part of what attracted me to him because it makes reading him feel like an arduous quest that promises high rewards. And it is quite true that with such a subtle and profound thinker, Nazism and anti-Semitism will take subtle and “profound” forms. But this does not mean that our judgment on them is not, in the end, simple. The most important thing we have to learn from Heidegger today is how the allure of profundity and authenticity can lead to the destruction of ethics and of thought itself.

Two extraordinary events demonstrate something important about Israel’s most fervent adversaries. One was a speech given at something called The People’s Forum (funded generously by Goldman Sachs), which stated, “When the state of Israel is finally destroyed and erased from history, that will be the single most important blow we can give to destroying capitalism and imperialism.”

The suggestion that this tiny state is the linchpin of a global, centuries-old phenomenon like capitalism goes well beyond anything resembling rational criticism. Even if Israel were guilty of genocide, apartheid, and oppression—which of course it is not—it would not follow that its destruction would help end capitalism or imperialism.

The other was an anti-Israel protest that took place in front of New York City’s Memorial Sloan Kettering Cancer Center, deemed “complicit” in Israel’s evils. At organizers’ urging, participants shouted their slogans at kids in the cancer ward, who were watching from the windows. Given Hamas’s indifference toward the lives of Gazan children, such callousness toward non-Palestinian children from Hamas’s Western allies shouldn’t be surprising. The protest—like the abovementioned speech—deliberately conveyed the message that Israel is the ultimate evil and its destruction the ultimate good, cancer patients be damned.

The fact that Israel’s adversaries are almost comically perverse does not mean that they can be dismissed. If its allies fail to understand the obsessive and irrational hatred that it faces, they cannot effectively help it defend itself.