It’s a truth only selectively acknowledged that all cultures are mongrel. One of the first Indian words to be brought into English was the Hindi ‘‘loot’’ — ‘‘plunder.’’ Some of the Ku Klux Klan's 19th-century costumes were, of all things, inspired in part by the festival wear of West African slaves; the traditional wax-print designs we associate with West Africa are apparently Indonesian — by way of the Netherlands. Gandhi cribbed nonviolence from the Sermon on the Mount.

We sometimes describe this mingling as ‘‘cross-pollination’’ or ‘‘cross-fertilization’’ — benign, bucolic metaphors that obscure the force of these encounters. When we wish to speak more plainly, we talk of ‘‘appropriation’’ — a word now associated with the white Western world’s co-opting of minority cultures. And this year — these past several months alone — there has been plenty of talk. In film, there was the outcry over the casting of the blonde Emma Stone as the part-Chinese Hawaiian heroine of Cameron Crowe’s ‘‘Aloha.’’ In music, Miley Cyrus wore dreadlock extensions while hosting the V.M.A.s and drew accusations of essentially performing in blackface — and not for the first time. In literature, there was the discovery that Michael Derrick Hudson, a white poet, had been published in this year’s Best American Poetry anthology under a Chinese pseudonym. In fashion, there was the odd attempt to rebrand cornrows as a Caucasian style — a ‘‘favorite resort hair look,’’ according to Elle. And floating above it all has been Rachel Dolezal, the presiding spirit of the phenomenon, the white former N.A.A.C.P. chapter president who remains serenely and implacably convinced of her blackness.

Questions about the right to your creation and labor, the right to your identity, emerge out of old wounds in America, and they provoke familiar battle stances. The same arguments are trotted out (It’s just hair! Stop being so sensitive! It’s not always about race!) to be met by the same quotes from Bell Hooks, whose essays from the early ’90s on pop culture, and specifically on Madonna, have been a template for discussions of how white people ‘‘colonize’’ black identity to feel transgressive: ‘‘Ethnicity becomes spice, seasoning that can liven up the dull dish that is mainstream white culture.’’ It’s a seasonal contro­versy that attends awards shows, music festivals, Halloween: In a country whose beginnings are so bound up in theft, conversations about appropriation are like a ceremonial staging of the nation’s original sins.

It can feel like such a poignantly stalled conversation that we’re occasionally tempted to believe we’ve moved past it. A 2013 NPR story on America’s changing demographics and the evolution of hip-hop made a case that the genre has lost its identification with race, and that young people aren’t burdened by anxieties about authenticity. ‘‘The melding of cultures we’re seeing now may have Generation X and Generation Y shaking in their boots with claims of racial ‘appropriation,’ ’’ the rapper and performance artist Mykki Blanco said in an online discussion about fashion’s debt to ‘‘urban culture.’’ ‘‘To Generation Z, I would clearly think it all seems ‘normal.’ ’’ Hip-hop culture is global culture, according to this wisdom: People of Korean descent have dominated the largest international b-boy championships; twerking is a full-blown obsession in Russia. ‘‘We as black people have to come to grips that hip-hop is a contagious culture,’’ Questlove, the drummer and co-founder of the Roots, said last year in an interview with Time magazine in which he defended Iggy Azalea, the white Australian rapper derided for (among other things) affecting a ‘‘Southern’’ accent. ‘‘If you love something, you gotta set it free.’’