This article critically examines the different ways in which American Enlightenment thinkers confronted the future of being white in the early republic as political economists, natural historians, physicians, and anatomists of the mind. Just as philosophes experimented on the nature of blackness in Bordeaux's Royal Academy of Sciences, the American Philosophical Society supported novel approaches to the racial classification of whiteness. An appeal to Scottish Enlightenment racial theories connected the diverging thought of Benjamin Franklin, Thomas Jefferson, Samuel Stanhope Smith, and (...) Benjamin Rush as prominent members of this society between 1743 and 1826. In doing so, Franklin industrialised the political economy of a ‘purely white’ nation. Jefferson naturalised the language of whiteness. Smith universalised the intellectual and moral cultivation of whiteness. And Rush medicalised an architype of a healthy mind and body as white. This article argues that Scottish philosophy informed radically different ideas about how to become white in the early American republic. (shrink)