Abstract
I will study the concept of solidarity by looking at patterns of practical reasoning leading to behaviour that can be taken to exemplify solidarity. By studying which kinds of premisses are necessary for taking the motivation to display solidarity, in contrast to altruistic or moral motivation, I try to find necessary conditions for solidarity. I will argue that practical reasoning leading to solidary behaviour is a form of we-reasoning in which some of the premisses are in first person plural form and attribute actions or attitudes to a collective. If this is correct, solidarity is a group concept, and intentional solidary behaviour presupposes identification with a group where others have shared goals or interests. This distinguishes solidary motivation and behaviour from altruistic or moral motivation and behaviour.