This paper proposes that several methodological imperatives should guide responsible and responsive theorising in order for any form of solidarity between philosophers and the vulnerable people they theorise about to be possible. As purveyors of conceptualisations, principles and critique, social and political philosophers contribute to public debates, often oblivious of how they tap into a community's political imaginary, sometimes challenging, other times reinforcing it. I propose that philosophers need to assume responsibility for how they conceptually carve out "reality" and for the normative assessment thereof, often enunciated from a position of authority. Moreover, in theorising, philosophers must be responsive to and solicit the voices of the vulnerable. Building on feminist and critical race theory and social epistemology, I first outline a vision of responsible and responsive theory, centred on practices of apprenticeship and playful world travelling, which have an affective dimension. I then introduce a methodological ethos that enables philosophers to participate reflexively in debates over difficult issues, contributing illuminating (rather than obscuring) ideas to the public hermeneutical pool of interpretive resources. I conclude by discussing how irresponsible and irresponsive theory dealt with a specific case of vulnerable people-migrants and refugees-thus foreclosing the very possibility of solidarity.