History of manifolds (incomplete, 2005). Diagram showing the development, with milestones; Outline of conceptual stages (lecture overheads).

"Theoretical mathematics": Toward a cultural synthesis of mathematics and theoretical physics (with Arthur Jaffe), Bulletin of the American Math. Soc. Vol. 29 (1993) pp. 1-13 link to journal. Explores the tension between math and physics and considers ways to alleviate it. Initiated an interesting debate in the community.

Response to comments on "Theoretical mathematics" , (with Arthur Jaffe), in Bulletin of the American Math. Soc. Vol. 30 (1994) pp. 208-211 link to journal. Responds to a wide variety of reactions solicited by the editors, in the same volume.

Cultural adaptation in mathematics and physics, preprint 1996 HTML version, PDF version. Expands on the idea that the subject matter influences the culture and social structure of scientific disciplines. Illustrates this by examining cultural conflicts between pure math and theoretical physics.