It made sense, to the New York Daily News sports editor, that these guys dominated basketball. After all, “the game places a premium on an alert, scheming mind and flashy trickiness, artful dodging and general smartalecness,” not to mention their “God-given better balance and speed.”

He was referring, of course, to the Jews.

In the 1930s, Paul Gallico was trying to explain away Jewish dominance of basketball. He came up with the idea that the game’s structure simply appealed to the immutable traits of wily Hebrews and their scheming minds. It sounds strange to the ear now, but only because our stereotypes about who is inherently good at particular sports have shifted. His theory is not any more or less insightful now than it was then; his confidence should remind us to be skeptical of similar, supposedly explanatory arguments that abound today.

Looking back at old stereotypes is a useful exercise; it can help illustrate the arbitrary nature of the concept of “race,” and how such identities shift even as people insist on their permanence and infallibility. Because race is not real, it is malleable enough to be made to serve the needs of those with the power to define it, the certainties of one generation giving way to the contradictory dogmas of another.

Whoopi Goldberg, the actor and a co-host of The View, stumbled into a public-relations nightmare for ABC on Monday when she insisted that “the Holocaust wasn’t about race.” After an episode of The Late Show With Stephen Colbert aired in which she opined that “the Nazis were white people, and most of the people they were attacking were white people,” she was temporarily suspended from The View. She has apologized for her remarks.

[Adam Serwer: White nationalism’s deep American roots]

I don’t mean to pile on Goldberg here, who I think is struggling with an American conception of “race” that renders the anti-Semitism that led to the Holocaust illegible. I regard her remarks not as malicious, but as an ignorant projection of that American conception onto circumstances to which it does not apply. In America, distinctions among European immigrants that were once considered deeply significant dissolved in the melting pot, leaving an absence in popular memory that might explain their salience elsewhere, and how someone could be seen as white in America and yet still be subject to persecution based on their “race.”

The Nazi Holocaust in Europe and slavery and Jim Crow in the United States are outgrowths of the same ideology—the belief that human beings can be delineated into categories that share immutable biological traits distinguishing them from one another and determining their potential and behavior. In Europe, with its history of anti-Jewish persecution and violent religious divisions, the conception of Jews as a biological “race” with particular characteristics was used by the Nazis to justify the Holocaust. In the United States, the invention of race was used to justify the institution of chattel slavery, on the basis that Black people were biologically suited to permanent servitude and unfit for the rights the nation’s Founders had proclaimed as universal. The American color line was therefore much more forgiving to European Jews than the divisions of the old country were. But they are branches of the same tree, the biological fiction of race.

In the United States, physical distinctions between most Black and most white people have misled some into thinking that the American conception of race is somehow more “real” than the racial fictions on which the Nazis based their campaign of extermination. Applying the American color line to Europe, the Holocaust appears merely to be a form of sectarian violence, “white people” attacking “white people,” which seems nonsensical. But those persecuting Jews in Europe saw Jews as beastly subhumans, an “alien race” whom they were justified in destroying in order to defend German “racial purity.” The “racial” distinctions between master and slave may be more familiar to Americans, but they were and are no more real than those between Gentile and Jew.

Adherence to religious belief was not required to be subject to Nazi persecution, and unlike some prior moments in European history, conversion was insufficient to escape danger. Jewish ancestry was enough, because it was ancestry—a person’s “race”—that made someone inescapably Jewish. In his infamous memoir, Adolf Hitler regretted that, early in life, he’d seen anti-Semitism as persecution of a people on the basis of religious belief, which he thought wrong. He later came to think of this as a Jewish lie to hide the reality that the Jewish people were a separate “race” whose goal was to enslave the rest of mankind. It should not be lost that enslaving all of mankind is a concise summary of Hitler’s own political project.

“Judaism predates Western categories. It’s not quite a religion, because one can be Jewish regardless of observance or specific belief,” my colleague Yair Rosenberg wrote. “But it’s also not quite a race, because people can convert in! It’s not merely a culture or an ethnicity, because that leaves out all the religious components.”

[Read: Are Jews white?]

This is all true, but Black Americans are not really a “race” either, and the borders of Black American identity can also be difficult to define or agree upon. To some extent, shared history, culture, and ancestry exist, but as the scholars Karen and Barbara Fields write in Racecraft, the very concept of race implies a material reality where none exists. Most American descendants  of the emancipated have white ancestry, and millions of white Americans with African ancestry have no knowledge of it. “Race is not an idea but an ideology. It came into existence at a discernible historical moment for rationally understandable historical reasons,” the Fieldses write, “and is subject to change for similar reasons.”

It is not necessary for race to be real for racism to be real. It is only necessary that people believe race to be real. When people act on fictions, those actions have repercussions even if the underlying belief is false—even if the people know that the underlying belief they are acting on is false. The fact that anti-Semitic conspiracy theories about Jewish control of the media, of governments, and of financial institutions are untrue does not rob them of their explanatory power for those who choose to believe in them. For Thomas Jefferson to know, somewhere in the disquiet of his own conscience, that slavery was a “cruel war against human nature itself” did not in and of itself grant freedom to those he owned as property.

“The people who settled the country had a fatal flaw. They could recognize a man when they saw one. They knew he wasn’t—I mean you can tell, they knew he wasn’t—anything else but a man; but since they were Christian, and since they had already decided that they came here to establish a free country, the only way to justify the role this chattel was playing in one’s life was to say that he was not a man,” James Baldwin wrote in 1964. “For if he wasn’t a man, then no crime had been committed.”

To this, we could add Jean-Paul Sartre’s observation that “if the Jew did not exist, the anti-Semite would invent him.” Race allows humanity to keep inventing, in language that can bend the most rational minds, groups of people whose supposed characteristics justify whatever cruelty we might wish to indulge.