%A William Clancey %J Cognitive Science Quarterly %T Is Abstraction a Kind of Idea or How Conceptualization Works? %X In this commentary, I review papers by Ohlsson & Regan (O&R), van Oers, and Dreyfus, Hershkowitz, & Schwarz (DH&S). The papers are nominally about abstraction and learning, but emphasize different kinds of problems and levels of analysis. O&R focus on mathematical, ?domain independent? characteristics of abstract thinking, claiming that experience in a domain is not the main determinant of scientific discovery. van Oers focuses on the development of abstraction within activities, especially as a sequence of nested domains of concern. DH&S emphasize how nested conceptualizations co-define and provide meaning for each other (a dialectic relation). %N 3-4 %P 389-421 %V 1 %D 2001 %L cogprints1988