In response to recent discussions of the possibility of writing global intellectual histories, this essay asks what that might involve for world regions beyond the West, particularly for ethnically and linguistically diverse areas that make up the necessarily complex units of analysis with which global historians must reckon. This methodological task is undertaken here by way of a case study of the Indian Ocean during the high tide of European colonization. Two dominant historiographical tropes are challenged to clear sufficient interpretive room for the variety of intellectual transactions across so heterogeneous a space. The first is the routine characterization of the Indian Ocean as an arena of "cosmopolitanism." The second is the premise that oceanic actors operated under the intellectual hegemony of a "colonial episteme." To test these claims, and widen the remit of what global intellectual history might mean, the focus here turns to the vernacular spheres of writing that rapidly widened in the era of print. Overall, the essay argues for understanding the Indian Ocean through an alternative conceptual framework of "vernacularism" and "heterotopia" that allows for the multiple intellectual trajectories of such world historical contact zones.