Simmel's concept of tact — the sensitivity to another person's unspoken feelings and unexpressed boundaries — the moral attention at the center of genuine sociability, and the capacity that structurally cannot be provided by any interlocutor that has no interior to protect.
Simmel defined sociability as the play-form of human interaction — the pure form of being-together that exists for its own sake, neither instrumental to some further purpose nor reducible to the content exchanged. At the center of genuine sociability is tact: not a social skill in the conventional sense but a form of moral attention, a way of recognizing that the other person has weight, that their interior life matters, that they deserve to be treated with care even when — especially when — that interior life has not been made explicit. Tact is the capacity to perceive what has not been said, to adjust without being asked, to maintain the delicate equilibrium between engagement and restraint. It is the word that anchors the epilogue of the Simmel volume and names what is structurally absent from the AI collaborator.