This article traces Hacking's “looping effect” in colonial policies and practices of taxation, coerced labour, and governance in Indonesia. It argues that knowledge production for the purpose of taxation was a two-way, interactive process which was in particular influenced by complexes of local indigenous social organization, institutions, mentalities, and behaviour as expressed through adat (Indonesian systems of political-social norms and customary law). Such patterns and systems, the article reveals, were internalized into and started working reciprocally with colonial policy, knowledge production, and administrative practices. Taxation made up and changed people, but underlying strategies to categorize and “make known” subjects were also recognized and actively used, evaded, or influenced by these subjects and by local intermediaries. Consequently, colonial knowledge created an institutional framework that reoriented the self-perception of these subjects and intermediaries, which then changed and reconditioned popular responses to the colonial state. Systems of colonial knowledge were thus modified to eventually fit the realities they were supposed to describe, influence, and legitimize, creating a looping effect between colonial, “made up,” and actual social realities.