This article introduces the idea of philosophical sociology as an enquiry into the relationships between implicit notions of human nature and explicit conceptualizations of social life within sociology. Philosophical sociology is also an invitation to reflect on the role of the normative in social life by looking at it sociologically and philosophically at the same: normative self-reflection is a fundamental aspect of sociology's scientific tasks because key sociological questions are, in the last instance, also philosophical ones. For the normative to emerge, we need to move away from the reductionism of hedonistic, essentialist or cynical conceptions of human nature and be able to grasp the conceptions of the good life, justice, democracy or freedom whose normative contents depend on more or less articulated conceptions of our shared humanity. The idea of philosophical sociology is then sustained on three main pillars and I use them to structure this article: (1) a revalorization of the relationships between sociology and philosophy; (2) a universalistic principle of humanity that works as a major regulative idea of sociological research, and; (3) an argument on the social (immanent) and pre-social (transcendental) sources of the normative in social life. As invitations to embrace posthuman cyborgs, non-human actants and material cultures proliferate, philosophical sociology offers the reminder that we still have to understand more fully who are the human beings that populate the social world.