What complicates things is that, as a rule, capitalizing a word doesn’t convey elevation: We don’t rank Masonite over mahogany. Written languages are not highly consistent, to be sure, so we generalize at some peril. But in English, the long-standing convention is to capitalize proper nouns and proper names, which are terms that refer to what philosophers call “particulars” or “individuals”—a specific person, place, or thing. We routinely name and capitalize entities (the Middle Ages, January, the Pacific Ocean, Copenhagen) that reflect human interests or actions. On the other hand, we tend not to capitalize “natural kinds”—that is, categories that track with inherent features of the world, independent of our interests or doings. Einstein, the physicist, is capitalized; einsteinium, the element, is not.
A good reason to capitalize the racial designation “black,” then, is precisely that black, in this sense, is not a natural category but a social one—a collective identity—with a particular history. (“Race is psychology, not biology” is a formulation Du Bois once offered.) What’s more, the very label “black” plays a role in generating that identity.
That’s how social identities work. The specific labels can shift over time (Negro, colored, Afro-American), but they help to bring into existence the group to which they refer. A pack of gray wolves exists regardless of our naming practices; they don’t need to know that they’re “gray wolves.” But to be black involves (among other things) identifying as black or being identified as black—usually both. Identity labels come with norms, and so a black person sometimes does things as a black person, is sometimes treated as a black person. (Because that treatment has its effects on you whether you like it or not, your race isn’t generally up to just you.) Social identities aren’t reducible to a label, but labels play a role in generating and sustaining them.
Conventions of capitalization can help signal that races aren’t natural categories, to be discovered in the world, but products of social forces. Giving black a big B could signal that it’s not a generic term for some feature of humanity but a name for a particular human-made entity. To paraphrase Simone de Beauvoir, one is not born, but rather becomes, black—and the same goes for all of our social identities.
So what about white folks? The style guide of the American Psychological Association declares, as it has for a generation: “Racial and ethnic groups are designated by proper nouns and are capitalized. Therefore, use ‘Black’ and ‘White’ instead of ‘black’ and ‘white.’” That seems sensible enough. But for some people, White is the sticking point. As The American Heritage Dictionary (on whose usage panel, now disbanded, I have served) ventured, in its fourth edition: “In all likelihood, uncertainty as to the mode of styling of white has dissuaded many publications from adopting the capitalized form Black.”