Reflections on threshold concepts in computer programming and beyond

I comment on and extend prior work that searches for threshold concepts in computer programming. I argue that explicitly linking threshold concepts to Brunerian fundamental ideas gives structure to the ongoing debate on threshold concepts. Program dynamics, information hiding and object interaction appear three strong candidates for threshold concepts in introductory programming, while abstraction and state seem to qualify as fundamental ideas. I further propose that the threshold concepts debate could benefit from the notion of transliminal concepts -- concepts that require an understanding of a threshold concept and can 'lure' students to and across thresholds.