Loneliness is commonly conceived of as a topic under the purview of psychology. Empirical research on loneliness utilizes a definition of psychology as essentially subjective, i.e. as a first-personal mental property an individual can have. As a first-personal mental property, subjects have, as it were, privileged access to their state of being lonely. Rehearsing some well-known arguments from later Wittgenstein, I argue that loneliness – contrary to an unargued assumption present in several academic engagements – is not subjective in the (...) sense that whether or not a person is lonely does not in all cases hinge on that person’s subjective mental states. This becomes apparent when considering cases of alienation from self-knowledge (Moran 2001). Using Heidegger’s notion of being-in-the-world and being-with I argue that such cases from alienation point towards the notion that loneliness is not merely a subjective feeling, but a categorically different privation of the fundamental mode of being with others. (shrink)