Building on ideas developed in 'The semiotic stance' (2005), this essay outlines a social and semiotic theory of four seemingly human-specific and individual-centric capacities that, while essential for understanding modern social processes, are often confused and conflated. Loosely speaking, agency is a causal capacity: say, the relatively flexible wielding of means towards ends. Subjectivity is a representational capacity: say, the holding of intentional states such as belief and desire. Selfhood is a reflexive capacity: say, being the means and ends of one's own actions, or being the object of one's own beliefs and desires. And personhood is a sociopolitical capacity: say, rights and responsibilities attendant on being an agent, subject or self.