Celebratio Mathematica

S. Mac Lane: “The pro­tean char­ac­ter of math­em­at­ics,” pp. 3–​13 in The space of math­em­at­ics: Philo­soph­ic­al, epi­stem­o­lo­gic­al, and his­tor­ic­al ex­plor­a­tions (San Se­bastiàn, Spain, Septem­ber 1990). Edi­ted by J. Echever­ria, A. Ibarra, and T. Mor­mann. Grundla­gen der Kom­munika­tion und Kog­ni­tion. de Gruyter (Ber­lin), 1992. MR 1214607 Zbl 0848.​00006 incollection