This chapter maps the fabrication and appropriation of positivism on a global scale. It particularizes and provincializes positivist universalism. Providing a comparative study of Auguste Comte's and John Stuart Mill's conceptions of positivism, it also shows how their disciples pioneered a universal, experience-based culture of scientific inquiry that encompassed nature and society, a new science to enlighten mankind and ameliorate their living conditions. Positivists envisaged one world united by science, but their efforts spawned many. Our fresh approach to global intellectual history demonstrates that positivism was no ready-made message recycled across the globe: initially grafted in response to the local problems of English and French societies, positivism was deracinated, tweaked, and adjusted while being re-elaborated by activists from Rio de Janeiro and Bengal, Istanbul and Vienna.