According to an important and influential definition in the literature, critical thinking is reasonable and reflective thinking focused on decisions about what to believe or what to do (Ennis, 1987), and it is considered to be a defining condition of higher education (Davies and Barnett 2015: 27). In some programmes (such as the IB Diploma Programme) it is something that is perhaps already developed in upper secondary schooling. While some authors consider critical thinking to be constituted by a cluster of dispositions or abilities (Ennis 2015), we consider critical thinking to be more of an attitude - more akin to an epistemic virtue than a set of procedures. We propose that the question of how to nurture such an attitude rests on situational factors in the university seminar room and that the university teacher plays a central role. 

 In this short presentation we focus on a single factor - the process of questioning - and suggest that critical thinking is nurtured and stimulated through questions that are open-ended, conceptually framed, and second order. The target of second-order questions is not factual information about the world itself, but rather concerns the relation between our knowledge of the world and the (thinking) processes needed in the production of this knowledge. The format in which we explore how to do this is by the use of Socratic dialogue.

Second-order questions possess multiple entry points for students - they can be interpreted differently depending on the current state of understanding of the student. Thereby they facilitate differentiated teaching/adaptive learning in the class or seminar supporting the cognitive development of a variety of students including those of high ability. This approach spawns a variety of applications in higher education from teacher training, to the humanities, and STEM disciplines.