Inspired by social interactionism (Weber 1921, Mead 1934) and the structuration theory (Giddens 1984), an emergent theory addresses social actions and discourses in terms of transactional horizons (Stoecklin 2021a, 2021b). New understandings of agency derived from an analytical framework called the “actor’s system” (Stoecklin 2013), stemming from long-term research with children in street situations (Lucchini and Stoecklin 2020). This framework was then applied in small-scale studies in Switzerland (Stoecklin et al. 2017; Stoecklin 2021b) and in a review of Greta Thunberg’s speeches (Stoecklin 2021a). The comparisons show that children’s participation, well-being, and attitudes towards sustainable development share a common feature that is the need for individual flourishing. This commonality in children’s experiences is grasped here with the notion “expansion of the self”. This provides a new understanding of the replicated claims for participation, well-being and sustainability: the need to flourish is bound to the most common system, namely the perceptual system. The five senses (touch, smell, hearing, sight, taste) are the human common basis for discursive collocations. An interdisciplinary dialogue is needed to understand actions as forms of being and connectors between perceptual and reflective consciousness.